生態(tài)與農(nóng)業(yè)氣象研究進(jìn)展

Progress in Ecological and Agricultural Meteorology Research

1 生態(tài)氣象

1 Ecological meteorology

1.1 Critical leaf water content for maize photosynthesis under drought stress and its response to rewatering

Crop photosynthesis is closely related to leaf water content (LWC), and clarifying the LWC conditions at critical points in crop photosynthesis has great theoretical and practical value for accurately monitoring drought and providing early drought warnings. This experiment was conducted to study the response of LWC to drought and rewatering and to determine the LWC at which maize photosynthesis reaches a maximum and minimum and thus changes from a state of stomatal limitation (SL) to non-stomatal limitation (NSL). The effects of rehydration were different after different levels of drought stress intensity at different growth stages,and the maize LWC recovered after rewatering following different drought stresses at the jointing stage;however, the maize LWC recovered more slowly after rewatering following 43 days and 36 days of drought stress at the tasseling and silking stages, respectively. The LWC when maize photosynthesis changed from SL to NSL was 75.4% ± 0.38%, implying that the maize became rehydrated under physiologically impaired conditions. The LWCs at which the maize Vcmax25reached maximum values and zero differed between the drought and rewatering periods. After exposure to drought stress, the maize exhibited enhanced drought stress tolerance, an obviously reduced suitable water range, and significantly weakened photosynthetic capacity.These results provide profound insight into the turning points in maize photosynthesis and their responses to drought and rewatering. They may also help to improve crop water management, which will be useful in coping with the increased frequency of drought and extreme weather events expected under global climate change. (Zhou Guangsheng)

1.2 Quantitative response of maize Vcmax25 to persistent drought stress at different growth stages

Drought stress has adverse effects on crop growth and yield, and its identification and monitoring play vital roles in precision crop water management. Accurately evaluating the effect of drought stress on crop photosynthetic capacity can provide a basis for decisions related to crop drought stress identification and monitoring as well as drought stress resistance and avoidance. In this study, the effects of different degrees of persistent droughts in different growth stages (3rd leaf stage, 7th leaf stage and jointing stage) on the maximum carboxylation rate at a reference temperature of 25 (Vcmax25) of the first fully expanded leaf and its relationship to the leaf water content (LWC) were studied in a field experiment from 2013 to 2015. The results indicated that the LWC decreased continuously as drought stress continued and that the LWC decreased faster in the treatment with more irrigation. Vcmax25showed a decreasing trend as the drought progressed but had no clear relationship to the growth stage in which the persistent drought occurred. Vcmax25showed a significantly parabolic relationship (R2= 0.701, p < 0.001) with the LWC, but the different degrees of persistent drought stress occurring in different growth stages had no distinct effect on the LWC values when Vcmax25reached its maximum value or zero. The findings of this study also suggested that the LWC was 82.5 ± 0.5% when Vcmax25reached its maximum value (42.6 ± 3.6 μmol m?2s?1) and 67.6 ± 1.2% (extreme drought) when Vcmax25reached zero. These findings will help to improve crop drought management and will be an important reference for crop drought identification, classification and monitoring as well as for the development of drought monitoring and early warning systems for other crops or maize varieties. (Zhou Guangsheng)

1.3 The interrelationship between water use efficiency and radiation use efficiency under progressive soil drying in maize

The maximizing of water use efficiency (WUE) and radiation use efficiency (RUE) is vital to improving crop production in dryland farming systems. However, the fundamental question as to the association of WUE with RUE and its underlying mechanism under limited-water availability remains contentious. Here, a twoyear field trial for maize designed with five progressive soil drying regimes applied at two different growth stages (three-leaf stage and seven-leaf stage) was conducted during the 2013–2014 growing seasons. Both environmental variables and maize growth traits at the leaf and canopy levels were measured during the soil drying process. The results showed that leaf WUE increased with irrigation reduction at the early stage, while it decreased with irrigation reduction at the later stage. Leaf RUE thoroughly decreased with irrigation reduction during the progressive soil drying process. Aboveground biomass (AGB), leaf area index (LAI), a fraction of absorbed photosynthetically active radiation (fAPAR), and light extinction coefficient (k) of the maize canopy were significantly decreased by water deficits regardless of the growth stages when soil drying applied. The interrelationships between WUE and RUE were linear across the leaf and canopy scales under different soil drying patterns. Specifically, a positive linear relationship between WUE and RUE is unexpectedly found when soil drying was applied at the three-leaf stage, while it turned out to be negative when soil drying was applied at the seven-leaf stage. Moreover, the interaction between canopy WUE and RUE was more regulated by fAPAR than by LAI under soil drying. Our findings suggest that more attention must be paid to fAPAR in evaluating the effect of drought on crops and may bring new insights into the interrelationships of water and radiation use processes in dryland agricultural ecosystems. (Zhou Guangsheng)

1.4 Capability of leaf water content and its threshold values in reflection of soil-plant water status in maize during prolonged drought

Leaves play an important role in plant growth and development through photosynthesis and transpiration.Many studies have explored the effects of short-term drought stress on leaf water status; however, few studies have focused on the leaf water content capacity as an indicator of soil-plant water status during prolonged droughts. The results of a field experiment with various irrigation regimes that was conducted during two consecutive maize growing seasons from 2013 to 2014, indicated that the water content of the first fully expanded leaf (LWCtop1) was representative of the soil–plant water status with the development of drought.LWCtop1 was closely linked to the water condition of other leaves and different plant parts in response to progressive water stress. LWCtop1 shared a quadratic relationship with the photosynthetic rate (Pn), and Pnpeaked when LWCtop1 approached 84.11% and decreased to zero when LWCtop1 dropped to 68.26%.Moreover, three stages (slow-fast-slow) were observed as leaf water content responded to soil drying, and two important threshold values (minimum: 70.86 ± 0.80%, maximum: 84.58 ± 1.10%) of the leaf water content were determined. The results of this study may provide a physiological and ecological basis for the identification and monitoring of crop drought. (Zhou Guangsheng)

1.5 Increasing temperature shortened the carbon uptake period and decreased the cumulative net ecosystem productivity in a maize cropland in Northeast China

Phenology—mainly associated with climatic factors—is crucial for the accurate estimation of cumulative annual carbon exchange between terrestrial ecosystems and the atmosphere. However, the effects of changes in phenology on annual vegetation productivity and its regulatory mechanisms remain unclear, particularly in agricultural ecosystems. Therefore, in this study, we examined the associations among cumulative net ecosystem productivity (NEP), phenological metrics, and climatic factors based on long-term (2005–2014)eddy covariance flux and meteorological observations in a maize cropland in Northeast China. The results showed that carbon uptake period (CUP) was mainly determined by the end date of CUP (ECUP) in autumn.Cumulative NEP from May to September (NEP5-9), a period generally corresponding to the growing season,significantly increased with NEPmax(defined in this study as the 90th percentile of daily NEP during CUP) and CUP. NEPmaxexplained greater interannual variation in NEP5-9 than CUP. The start date of CUP (SCUP) and ECUP were both advanced with increasing winter temperature, but ECUP was more temperature-sensitive than SCUP. Thus, CUP tended to shorten with increasing temperature, ultimately decreasing cumulative NEP. In addition, NEPmaxdecreased with increasing precipitation in summer and autumn. The Greenup and MidGreendown dates from the MODIS Global Vegetation Phenology (MCD12Q2) product generally captured the interannual variation in the carbon flux-based SCUP and ECUP, respectively, well. The results of this study would be of great significance for predicting the response of ecosystem productivity to plant phenology shifts in agricultural ecosystems in future climate change scenarios. (Zhou Guangsheng)

1.6 Climatic warming enhances soil respiration resilience in an arid ecosystem

Precipitation plays a vital role in maintaining desert ecosystems in which rain events after drought cause soil respiration (Rs) pulses. However, this process and its underlying mechanism remain ambiguous,particularly under climatic warming conditions. This study aims to determine the magnitude and drive Rsof Rsresilience to rewetting. We conducted a warming experiment in situ in a desert steppe with three climatic warming scenarios—ambient temperature as the control, long-term and moderate warming treatment, and short-term and acute warming treatment. Our findings showed that the average Rsover the measurement period in the control, moderate and acute warming plots were 0.51, 0.30 and 0.30 μm(CO2) m?2s?1, respectively, and significantly increased to 1.72, 1.41 and 1.72 μm(CO2) m?2s?1, respectively, after rewetting. Both microbial and root respiration substantially increased by rewetting; microbial respiration contributed more than root respiration to total Rs. The Rssignificantly increased with microbial biomass carbon and soil organic carbon(SOC) contents. The Rsincrease by rewetting might be due to the greater microbial respiration relying heavily on microbial biomass and the larger amount of available SOC after rewetting. A trackable pattern of Rsresilience changes occurred during the daytime. The resilience of Rsin acute warming plots was significantly higher than those in both moderate warming and no warming plots, indicating that Rsresilience might be enhanced with drought severity induced by climatic warming. These results suggest that climatic warming treatment would enhance the drought resilience of soil carbon effluxes following rewatering in arid ecosystems,consequently accelerating the positive feedback of climate change. Therefore, this information should be included in carbon cycle models to accurately assess ecosystem carbon budgets with future climate change scenarios in terrestrial ecosystems, particularly in arid areas. （Zhou Guangsheng）

1.7 Resistance, recovery, and resilience of desert steppe to precipitation alterations with nitrogen deposition

Precipitation fluctuations with high nitrogen (N) deposition severely impact terrestrial ecosystem functioning, particularly in arid areas. Here, with rainout shelter facility, a field experiment with a large variation in precipitation and N addition was conducted to disentangle the responses of the plant community to normal precipitation, less precipitation, and rewetting conditions in a desert steppe, Inner Mongolia, the northern China. The field experiment established a unique annual precipitation change cycle across normal precipitation, less precipitation, and rewetting processes to quantify drought resistance, recovery, and resilience by calculating functional differences among three years. Furthermore, the relationships between plant community functional traits and response indices (i.e., the resistance, recovery, and resilience) were tested to clarify the mechanisms driving their responses to precipitation regimes and N addition. The aboveground net primary production (ANPP) increased with annual precipitation and was enhanced by N addition. ANPP with reduced precipitation regimes was less resistant to drought but recovered significantly greater than that with increased precipitation regimes. The perennial species, C3 plants, and forbs mainly contributed to the variations in vegetation productivity in response to drought and wet status cycles. Drought resistance and the recovery of species’ functional diversity, evenness, and ANPP stability were closely associated with precipitation changes. The present findings suggested that altered precipitation patterns, community composition, and functional stability contribute to ecosystem stability during water change cycles and are mediated slightly by N deposition. These findings advance understanding of the mechanisms of ecosystem functioning underlying the responses to climatic change. （Zhou Guangsheng）

1.8 Vertical distribution of gas exchanges and their integration throughout the entire canopy in a maize field

Fluxes of carbon and water along a vertical profile within a canopy, particularly the associations between canopy and ecosystem levels, are not well studied. In this study, gas exchange along the vertical profile in a maize canopy was examined. The relationships between leaf- and ecosystem-level carbon and water fluxes were compared. The results from research conducted over two growing seasons showed that during vegetative growth, the top and middle leaf layers in the canopy contribute most to the carbon and water fluxes of the entire canopy. During the grain-filling stage, gas exchange processes were performed mostly in the middle leaves with and near the ears. Significant relationships were observed between the net ecosystem CO2exchange rate(NEE) plus soil respiration and the assumed canopy levels (Acanopy) and between evapotranspiration rates at the ecosystem (ET) and assumed canopy levels (Ecanopy). This highlights the close associations between these parameters by integrating the leaf gas exchange rates measured in a conventional leaf cuvette and those at the ecosystem level via the eddy covariance technique. These results improve our understanding of how carbon assimilation varies vertically within a canopy, highlighting the critical role of ear leaves. （Zhou Guangsheng）

1.9 Effects of mosaic representation of land use/land cover on skin temperature and energy fluxes in Noah-MP land surface model over China

The representations of land use/land cover (LULC) play an important role in land surface models (LSMs)for the simulation of the energy flux partition, soil moisture redistribution, and runoff generation. This study was designed to investigate the regional effects of mosaic LULC representations on skin temperature (Ts) and energy fluxes over China at three horizontal resolutions and how these effects changed with climate regimes,using Noah with multi-parameterization (Noah-MP) LSM. The current officially released Noah-MP only considered the most abundant LULC type within one model grid. In this study, the mosaic method considering all the LULC types existing in one model grid was implemented into Noah-MP. Against the reference data(including MODIS land surface temperature products, FLUXCOM energy flux data and numerical terra dynamic simulation group evapotranspiration data), the mosaic method generally performed better than the default method and reduced the root-mean-squared-error of Tsand energy fluxes significantly over urban region. The mosaic method affected the Tsand energy fluxes by changing leaf area index and soil moisture,mainly by the former. The warm (monthly mean air temperature larger than 10 ) and relatively humid climate(annual total precipitation larger than 200 mm) could enlarge the effect of mosaic method on Tsand energy fluxes. The mosaic method reduced discrepancies of Tsand energy fluxes among three horizontal resolutions(0.0625o, 0.25o, and 0.50o), especially over the heterogeneous vegetated and urban region. （Zhou Guangsheng）

1.10 Climate warming-induced drought constrains vegetation productivity by weakening the temporal stability of the plant community in an arid grassland ecosystem

An investigation of the influences of climatic warming on ecosystem function and stability is crucial to project the impact of global climate change on terrestrial ecosystems. However, few studies have applied multiple warming treatments in arid ecosystems, which play a critical role in the global carbon cycle and are among the ecosystems most sensitive to future climatic change. To explore the effects of climatic warming on plant community function and stability, moderate warming and acute warming treatments were conducted in desert grassland, Inner Mongolia, China, using free-air temperature increase facilities. Aboveground net primary production (ANPP) of plant community significantly decreased with climatic warming, particularly in warmer years with drier conditions. The decrease in ANPP was mainly caused by decreased soil moisture induced by climatic warming. Climatic warming reduced the temporal stability of the plant community by weakening plant species asynchrony and shifting key functional groups, such as perennial vs annual grass and C3 vs C4 species. Our findings indicate that climatic warming could hamper plant community productivity via decreased soil moisture and constrain plant community functioning by weakening community stability. This result highlights that shifts in plant community composition and consequent functional changes can play a key role in predicting the responses of arid ecosystems to climatic change. （Zhou Guangsheng）

1.11 Photosynthetic resistance and resilience under drought, flooding and rewatering in maize plants

Abnormally altered precipitation patterns induced by climate change have profound global effects on crop production. However, the plant functional responses to various precipitation regimes remain unclear. Here,greenhouse and field experiments were conducted to determine how maize plant functional traits respond to drought, flooding, and rewatering. Drought and flooding hampered photosynthetic capacity, particularly when severe and/or prolonged. Most photosynthetic traits recovered after rewatering, with few compensatory responses. Rewatering often elicited high photosynthetic resilience in plants exposed to severe drought at the end of plant development, with the response strongly depending on the drought severity/duration. The associations of chlorophyll concentrations with photosynthetically functional activities were stronger during post-tasseling than during pre-tasseling, implying an involvement of leaf age/senescence in responses to episodic drought and subsequent rewatering. Coordinated changes in chlorophyll content, gas exchange,fluorescence parameters (PSII quantum efficiency and photochemical/non-photochemical radiative energy dissipation) possibly contributed to the enhanced drought resistance and resilience and suggested a possible regulative trade-off. These findings provide fundamental insights into how plants regulate their functional traits to deal with sporadic alterations in precipitation. Breeding and management of plants with high resistance and resilience traits could help crop production under future climate change. （Zhou Guangsheng）

1.12 Quantitative evaluation of the trade-off growth strategies of maize leaves under different drought severities

The leaf is one of the most drought-sensitive plant organs. Investigating how leaf traits change and their trade-off growth during a drought would contribute to developing targeted drought-resistance measures. We investigated changes in five key maize leaf traits (leaf area, dry mass, effective number, water content, and specific weight) and their trade-off growth based on a drought simulation experiment. We also developed an indicator (0, 1) to quantitatively evaluate drought severity. The results showed a trade-off growth between different leaf traits of maize plants under drought conditions. Maize maintained relatively high leaf water content to maintain high leaf metabolic activity until drought severity was greater than 0. When drought severity was (0, 0.48), maize tended to adopt rapid growth strategy by maintaining regular leafing intensity and investing more energy into leaf area rather than specific leaf weight so that more energy could be absorbed.When the drought severity exceeded 0.48, maize conserved its resources for survival by maintaining relatively lower metabolic activity and thicker leaves to minimize water loss. The results provide an insight into the acclimation strategies of maize under drought, and contribute to targeted drought prevention and relief measures to reduce drought-induced risks to food security. （Zhou Guangsheng）

1.13 Growth variations of dahurian larch plantations across Northeast China: Understanding the effects of temperature and precipitation

Climate change is affecting the growth and distribution of trees in the Chinese boreal forest. Such changes in China, the southern terminus of the extensive Eurasian boreal forests, reflect on the changes that could occur further north under a warming climate. Most studies have found that tree growth increases with increasing temperature and precipitation in boreal forests, but there is little observational evidence of the climate thresholds that might slow these growth rates at the more extreme temperatures which are predicted to occur under future global warming. Here, we examine growth responses of this dominant boreal tree species (Larix gmelinii) to climate based on the data from plantation sample plots across a broad region (40o51'–52o58' N,118o12'E?133o42' E) in Northeast China. From statistically significant fits to quadratic equations, temperature and precipitation are the important climatic factors determining tree growth in L. gmelinii plantations at two age classes (<10 year and 10–30 years-old stands). The maximum rates of tree height and diameter at breast height (DBH) were about 0.53 m year?1and 0.46 cm year?1at <10 year stands, and about 0.63 m/year and 0.60 cm/year at 10–30-year stands, respectively. For stands with the highest values of mean annual increment(MAI), the corresponding optimal mean annual temperature (MATopt) focused between 0.66 and 1.57 .The optimal mean annual precipitation (MAPopt) between 663 mm and 708 mm produced the maximal growth increments. With mean annual temperature of ?2.4 and precipitation of 470 mm averaged over 1954–2005 in Chinese boreal forest region as baseline, we conservatively estimated that trees in Chinese boreal forest appear to have higher growth potentials with the maximum temperature increase of 3.6 and precipitation increase of 40%. （Zhou Guangsheng）

1.14 Responses of plant biomass and yield component in rice, wheat, and maize to climatic warming: A meta-analysis

The responses of crop yields to climatic warming have been extensively reported from experimental results, historical yield collections, and modeling research. However, an integrative report on the responses of plant biomass and yield components of three major crops to experimental warming is lacking. Here, a metaanalysis based on the most recent warming experiments was conducted to quantify the climatic warming responses of the biomass, grain yield (GY), and yield components of three staple crops. The results showed that the wheat total aboveground biomass (TAGB) increased by 6.0% with general warming, while the wheat GY did not significantly respond to warming; however, the responses shifted with increases in the mean growing season temperature (MGST). Negative effects on wheat TAGB and GY appeared when the MGSTs were above 15 and 13 , respectively. The wheat GY and the number of grains per panicle decreased by 8.4% and 7.5%, respectively, per increase. Increases in temperature significantly reduced the rice TAGB and GY by 4.3% and 16.6%, respectively, but rice straw biomass increased with increasing temperature. However,the rice grain weight and the number of panicles decreased with continuous increasing temperature (ΔTa). The maize biomass, GY, and yield components all generally decreased with climatic warming. Finally, the crop responses to climatic warming were significantly influenced by warming time, warming treatment facility, and methods. Our findings can improve the assessment of crop responses to climatic warming and are useful for ensuring food security while combating future global climate change. （Zhou Guangsheng）

1.15 ChinaSpec: A network for long-term ground-based measurements of solar-induced fluorescence in China

Remotely sensed solar-induced fluorescence (SIF) has emerged as a novel and powerful approach for terrestrial vegetation monitoring. Continuous measurements of SIF in synergy with concurrent eddy covariance(EC) flux measurements can provide a new opportunity to advance terrestrial ecosystem science. Here, we introduce a network of ground-based continuous SIF observations at flux tower sites across the mainland China referred to as ChinaSpec. The network consists of 16 tower sites until 2019 including six cropland sites, four grassland sites, four forest sites, and two wetland sites. An automated SIF system was deployed at each of these sites to collect continuous high-resolution spectra for high-frequency SIF retrievals in synergy with EC flux measurements. The goal of ChinaSpec is to provide long-term ground-based SIF measurements and promote the collaborations between optical remote sensing and EC flux observation communities in China. We present here the details of instrument specifications, data collection and processing procedures, data sharing and utilization protocols, and future plans. Furthermore, we show the examples how ground-based SIF observations can be used to track vegetation photosynthesis from diurnal to seasonal scales, and to assist in the validation of fluorescence models and satellite SIF products (e.g., from OCO-2 and TROPOMI) with the measurements from these sites since 2016. This network of SIF observations could improve our understanding of the controls on the biosphere-atmosphere carbon exchange and enable the improvement of carbon flux predictions. It will also help integrate ground-based SIF measurements with EC flux networks which will advance ecosystem and carbon cycle researches globally. （Zhou Guangsheng）

1.16 Grated remote sensing and model approach for impact assessment of future climate change on the carbon budget of global forest ecosystems

At present, global warming is an indisputable fact, and more and more attention has been paid to the impacts of climate warming on global ecological environments. Forests play increasing significant roles in regulating global carbon balance and mitigating climate change. Therefore, to understand the response mechanisms of the carbon budget of global forest ecosystems to future climate change, an improved version of the FORest ecosystem Carbon budget model for CHiNa (FORCCHN) and future Representative Concentration Pathway (RCP) scenario RCP4.5 and RCP8.5 were applied in this study. The results demonstrated that the global forest ecosystems will play a major role in the carbon sink under the future two climate change scenarios. In particular, the average carbon budget of global forest ecosystems under RCP4.5 scenario was estimated to be 0.017 kg(C) m?2yr?1from 2007 to 2100. The future carbon sink areas of global forest ecosystems will increase significantly. Under RCP4.5 and RCP8.5 climate scenarios, the carbon sink areas of global forest ecosystems during 2026?2100 would be significantly been expanded than those in 2007?2025,with increases of 83.16%?87.26% and 23.53%?29.70%, respectively. The impacts of future climate change on carbon budget of global forest ecosystems will significantly vary between different regions. The carbon budget of forests will be enhanced in the Northern Hemisphere and significantly weakened in the Southern Hemisphere under the future two climate change scenarios. The carbon sink regions of global forests will be mainly distributed in the middle and high latitudes of the Northern Hemisphere. In particular, the forests’carbon budget in the northeastern and central Asia, northern Europe and western North America will increase by 40% to 80%. However, the carbon budget of forests will decrease by 20% to 40% in the most regions of the Southern Hemisphere. In northern South America and central Africa, the forests’ carbon budget will be reduced by more than 40%. In the future, in some areas of Southern Hemisphere, where the forests’ carbon budget was predicted to be reduced, some measures for improving forest carbon sink, such as strengthening forest tending,enforcing prohibiting deforestation laws and scientific forest management, and so on, should be implemented to ensure immediate mitigation and adaptation to climate change. (Zhao Junfang)

1.17 Analysis of wheat yield losses at the county level in mainland China

There have been few pieces of research focused on quantifying wheat yield loss risk based on highresolution long-term historical data. What is more, the existence of the area scale effect reduces the certainty and spatial comparability of results. In this study, long-term wheat yield and planting area data at the county level from 1981 to 2010 were used. The spatial distribution of wheat yield loss risks was analyzed in the mainland of the People’s Republic of China (China for short). An improved comprehensive risk index of yield loss risk was established by integrating the reduction rate, coefficient of variation, and the probability of occurrence for different yield reduction rates after removing the effect of area scale. The main wheat-growing areas of 874 counties in the mainland of China were divided into lowest, lower, moderate, higher, and highest risk areas based on it. The high-risk areas are located in the Yellow-Huai-Hai Plain, including Shandong,Henan, northern Anhui, and parts of Jiangsu Province. （Fang Shibo）

1.18 Using long-term earth observation data to reveal the factors contributing to the early 2020 desert locust upsurge and the resulting vegetation loss

Massive desert locust swarms have been threatening and devouring natural vegetation and agricultural crops in East Africa and West Asia since 2019, and the event developed into a rare and globally concerning locust upsurge in early 2020. The breeding, maturation, concentration and migration of locusts rely on appropriate environmental factors, mainly precipitation, temperature, vegetation coverage and land-surface soil moisture. Remotely sensed images and long-term meteorological observations across the desert locust invasion area were analyzed to explore the complex drivers, vegetation losses and growing trends during the locust upsurge in this study. The results revealed that (1) the intense precipitation events in the Arabian Peninsula during 2018 provided suitable soil moisture and lush vegetation, thus promoting locust breeding, multiplication and gregarization; (2) the regions affected by the heavy rainfall in 2019 shifted from the Arabian Peninsula to West Asia and Northeast Africa, thus driving the vast locust swarms migrating into those regions and causing enormous vegetation loss; (3) the soil moisture and NDVI anomalies corresponded well with the locust swarm movements; and (4) there was a low chance the eastwardly migrating locust swarms would fly into the Indochina Peninsula and Southwest China. （Fang Shibo）

1.19 Analyzing the probability of acquiring cloud-free imagery in China with AVHRR cloud mask data

Optical remote sensing data are used widely in many fields (such as agriculture, resource management and the environment), especially for the vast territory of China; however, the application of these data is usually limited by clouds. Although it is valuable to analyze the probability of acquiring cloud-free imagery (PACI),PACI using different sensors at the pixel level across China has not been reported. In this study, the PACI of China was calculated with daily advanced very high resolution radiometer (AVHRR) cloud mask data from 1990 to 2019. The results showed that (1) PACI varies dramatically in different regions and months in China.The value was larger in autumn and winter, and the largest figure reached 49.55% in October in Inner Mongolia(NM). In contrast, relatively small values occurred in summer, and the minimum value (5.26%) occurred in June in South China (SC). (2) As the climate changes, the PACI has increased significantly throughout the country, especially in North China (NC), with a growth rate of 1.9% per decade. The results can be used as a reference for selecting appropriate optical sensors and observation times in areas of interest. （Fang Shibo）

1.20 Analysis of variation in reference evapotranspiration and its driving factors in mainland China from 1960 to 2016

Understanding the variation in reference evapotranspiration (ET0) is vital for hydrological cycles, drought monitoring, and water resource management. With 1507 meteorological stations and 130 radiation-measured stations, the annual and seasonal ET0were calculated at each site from 1960 to 2016 in mainland China. The phenomenon of coefficient a being less than 0.25 and coefficient b being greater than 0.50 in the Angstrom–Prescott model occurred in almost the whole country, except for a small area of western and northeastern China. Moreover, the Xiao’s method was more applicable to calculate the net longwave radiation (Rnl) and then improve the estimation accuracy of ET0. The annual ET0varied from 538.8 to 1559.8 mm and had a high-value center located in the plateau and desert of the northwestern China and a low-value center located in Northeast China and near the Sichuan Basin. The spatial distribution of seasonal ET0was roughly similar to that of annual ET0, except for that in winter when ET0was high in the south and low in the north. In mainland China,the annual ET0decreased by 21.2 mm per decade because of the declining sunshine duration before 1993 and increased by 21.1 mm per decade due to the decreased relative humidity (RH) after 1993. Generally, the abrupt change of ET0mainly occurred in the southern China rather than northern China (except for Qinghai Tibet Plateau). Basically, the dominant driving factors of annual and seasonal ET0were RH and/or Tmaxafter the abrupt change in most parts of China. （Fang Shibo）

1.21 New aricultural drought index for monitoring the water stress of winter wheat

Timely and effectively monitoring agricultural droughts for winter wheat production is crucial for water resource management, drought mitigation and even national food security. With soil moisture and actual evapotranspiration (ET) products from 2001 to 2018 supplied by the European Centre for Medium-Range Weather Forecasts (ECMWF) and moderate resolution imaging spectroradiometer (MODIS) data, respectively,two agricultural drought indices, i.e., the univariate soil moisture and evapotranspiration index (USMEI) and bivariate soil moisture and evapotranspiration index (BSMEI), were developed to reflect water stress for winter wheat. Our case study on the North China Plain (NCP) indicated that the USMEI could effectively monitor agricultural drought, especially in autumn and winter from October to January. Furthermore, compared with the evaporative stress index (ESI) and soil moisture anomaly percentage index (SMAPI), the correlations between the USMEI and climatic yields were acceptable at the county level or site scale. However, for the rest of the winter wheat growing season, the ESI and SMAPI performed better than the USMEI. In addition,the BSMEI was not suitable for monitoring droughts for winter wheat because this index overestimated the drought intensity. （Fang Shibo）

1.22 生態(tài)氣象：起源、概念和展望

生態(tài)氣象是應(yīng)人類(lèi)面臨的生存環(huán)境危機(jī)而興起的地球系統(tǒng)科學(xué)新興學(xué)科，已經(jīng)成為大氣科學(xué)的二級(jí)學(xué)科。本文闡述了生態(tài)氣象的學(xué)科起源、概念、主要研究?jī)?nèi)容與特征，指出生態(tài)氣象是研究生態(tài)系統(tǒng)與氣象條件之間相互關(guān)系的科學(xué)，是地球系統(tǒng)多圈層相互作用的核心，服務(wù)于人與自然和諧發(fā)展；探討了生態(tài)氣象觀(guān)測(cè)的主要指標(biāo)與可能的業(yè)務(wù)服務(wù)產(chǎn)品；闡釋了生態(tài)氣象研究與生態(tài)文明氣象保障、氣象防災(zāi)減災(zāi)和應(yīng)對(duì)氣候變化的關(guān)系。當(dāng)前生態(tài)氣象迫切需要開(kāi)展的重點(diǎn)研究任務(wù)如下：（1）生態(tài)氣象長(zhǎng)期觀(guān)測(cè)聯(lián)網(wǎng)研究；（2） 基于大數(shù)據(jù)與人工智能的生態(tài)氣象信息提取與分析技術(shù)； （3） 生態(tài)系統(tǒng)對(duì)氣候變化的適應(yīng)性及其變化歸因； （4） 生態(tài)系統(tǒng)主要?dú)庀鬄?zāi)變機(jī)制及其致災(zāi)臨界氣象條件； （5） 陸地生態(tài)系統(tǒng)關(guān)鍵物候期對(duì)多環(huán)境要素響應(yīng)的生理生態(tài)機(jī)制與模擬模型研究； （6） 耦合生物—物理—化學(xué)—管理過(guò)程的生態(tài)氣象數(shù)值模式研發(fā)； （7） 陸地生態(tài)系統(tǒng)變化對(duì)氣候系統(tǒng)的反饋?zhàn)饔门c可持續(xù)發(fā)展對(duì)策研究。（周廣勝）

1.23 河水生態(tài)承載力的流域整體性和時(shí)空連通性

黃河是中華民族的母親河，黃河流域是中華文明的重要發(fā)育地。在中國(guó)5000多年的歷史長(zhǎng)河中，黃河流域作為全國(guó)政治、經(jīng)濟(jì)和文化中心占據(jù)了3000多年，孕育了河洛文化、河湟文化、關(guān)中文化等，分布有西安、鄭州、洛陽(yáng)、開(kāi)封等古都，誕生了四大發(fā)明和《詩(shī)經(jīng)》《老子》《史記》等經(jīng)典著作。黃河流域是連接青藏高原、黃土高原和華北平原的生態(tài)廊道，是西北和華北地區(qū)的重要水源，以其占全國(guó)2.2%的徑流量灌溉了占全國(guó)15%的耕地，哺育了流域9省近23.3%的全國(guó)人口（2019年），貢獻(xiàn)了21.6%的全國(guó)GDP（2018年）。不僅如此，黃河流域還是中國(guó)最重要的煤炭生產(chǎn)地帶。中國(guó)排名前14的大型煤炭生產(chǎn)基地中有9個(gè)地處黃河流域，已經(jīng)探明的煤炭?jī)?chǔ)量累計(jì)達(dá)7292億噸（原煤）。特別是，煤炭工業(yè)已經(jīng)成為黃河流域中、上游晉陜蒙寧甘地區(qū)（即山西、陜西、內(nèi)蒙古、寧夏和甘肅五省區(qū)）經(jīng)濟(jì)發(fā)展的主要經(jīng)濟(jì)支柱產(chǎn)業(yè)，煤炭年產(chǎn)量約28億t，占全國(guó)總產(chǎn)量的近70%。因此，黃河流域生態(tài)保護(hù)和高質(zhì)量發(fā)展直接關(guān)系到中國(guó)生態(tài)文明建設(shè)的成敗。長(zhǎng)期以來(lái)，黃河存在水土流失、泥沙淤積和洪水威脅等問(wèn)題。特別是近幾十年來(lái)，黃河流域氣溫升高、極端事件及自然災(zāi)害頻發(fā)，徑流減少；同時(shí)，大規(guī)模的能源開(kāi)發(fā)、煤炭開(kāi)采也需要大量的水資源。氣候變化和不合理人類(lèi)活動(dòng)使得黃河上游部分生態(tài)系統(tǒng)質(zhì)量退化、水源涵養(yǎng)功能下降；中游水土流失嚴(yán)重；下游生態(tài)流量偏低，部分河口濕地萎縮。目前，黃河流域水資源短缺、自然生態(tài)脆弱、經(jīng)濟(jì)社會(huì)發(fā)展相對(duì)滯后，是中國(guó)生態(tài)安全保障和經(jīng)濟(jì)社會(huì)發(fā)展的重點(diǎn)和難點(diǎn)地區(qū)。為此，需要梳理制約黃河流域生態(tài)保護(hù)與高質(zhì)量可持續(xù)發(fā)展存在的問(wèn)題，凝煉關(guān)鍵科學(xué)問(wèn)題，提出當(dāng)前迫切需要開(kāi)展的任務(wù)。（周廣勝）

1.24 中國(guó)生態(tài)與農(nóng)業(yè)氣象研究進(jìn)展

目前中國(guó)生態(tài)與農(nóng)業(yè)氣象研究主要關(guān)注氣候變化的影響，而脆弱性與風(fēng)險(xiǎn)預(yù)估研究仍存在很大不確定性，甚至無(wú)法進(jìn)行預(yù)估研究。以生態(tài)/農(nóng)業(yè)氣象的脆弱性和風(fēng)險(xiǎn)為切入點(diǎn)，從生態(tài)/農(nóng)業(yè)的地理/種植分布、物候/生育期和生產(chǎn)力/產(chǎn)量等方面，綜述了中國(guó)生態(tài)/農(nóng)業(yè)氣象的研究進(jìn)展，指出現(xiàn)有研究成果難以滿(mǎn)足高質(zhì)量生態(tài)保護(hù)與糧食安全的需求，為此提出了未來(lái)擬重點(diǎn)開(kāi)展的研究任務(wù)，即生態(tài)/農(nóng)業(yè)氣象承載力及其優(yōu)化布局、生態(tài)/農(nóng)業(yè)氣象的災(zāi)變過(guò)程與調(diào)控機(jī)制、生態(tài)/農(nóng)業(yè)變化的氣象條件貢獻(xiàn)率評(píng)估及其適應(yīng)技術(shù)、高質(zhì)量生態(tài)保護(hù)與糧食提質(zhì)增效的氣候資源高效利用和定向調(diào)控研究，以推進(jìn)中國(guó)生態(tài)與農(nóng)業(yè)氣象脆弱性與風(fēng)險(xiǎn)研究，為中國(guó)生態(tài)/農(nóng)業(yè)氣象科學(xué)應(yīng)對(duì)氣候變化提供依據(jù)。（周廣勝）

1.25 2000—2019年秦嶺地區(qū)植被生態(tài)質(zhì)量演變特征及驅(qū)動(dòng)力分析

為了闡明2000—2019年秦嶺地區(qū)植被生態(tài)質(zhì)量變化的空間異質(zhì)性，以及植被生態(tài)質(zhì)量變化的驅(qū)動(dòng)力，該文采用模型模擬和衛(wèi)星觀(guān)測(cè)的方法對(duì)植被生態(tài)質(zhì)量演變及其驅(qū)動(dòng)力進(jìn)行研究。結(jié)果顯示：（1）秦嶺地區(qū)植被生態(tài)質(zhì)量整體顯著改善，植被凈初級(jí)生產(chǎn)力（NPP）和植被覆蓋度（VFC）的平均增加速率分別為8 g（C）/（m2·a）和0.0054/a?？臻g上，秦嶺地區(qū)85%～95%區(qū)域的植被生態(tài)質(zhì)量明顯改善，但是以西安市為代表的局部地區(qū)植被NPP和VFC顯著下降。（2）秦嶺地區(qū)80%～85%區(qū)域的降水量和氣溫呈上升趨勢(shì)，與植被NPP和VFC增加的空間范圍大體一致，證實(shí)氣候暖濕化對(duì)改善植被質(zhì)量有重要驅(qū)動(dòng)作用。（3）人類(lèi)保護(hù)活動(dòng)（天然林保護(hù)、退耕還林還草等）使秦嶺地區(qū)大范圍植被生態(tài)系統(tǒng)得到撫育，林地、草地和水域面積大幅度增加。以秦嶺北麓為代表的建設(shè)用地?cái)U(kuò)張是秦嶺部分地區(qū)植被生態(tài)質(zhì)量惡化的主要原因，但是人類(lèi)破壞活動(dòng)被限制在局部區(qū)域。（周廣勝）

1.26 增溫背景下克氏針茅枯黃期物候?qū)邓憫?yīng)的光合生理機(jī)制

基于紅外線(xiàn)輻射增溫與控水相結(jié)合的原位模擬試驗(yàn)資料，分析了克氏針茅（Stipa krylovii）枯黃期對(duì)水熱變化響應(yīng)的光合生理機(jī)制。結(jié)果表明，增溫背景下降水是枯黃期的主要影響因子，增水（減水）導(dǎo)致枯黃始期和枯黃盛期的發(fā)生時(shí)間均延遲（提前），枯黃期持續(xù)時(shí)間均延長(zhǎng)，減水處理對(duì)枯黃期持續(xù)時(shí)間的延長(zhǎng)作用更顯著。增溫背景下，降水變化顯著影響枯黃期的生理生態(tài)特性，且在枯黃始期最為顯著，凈光合速率、氣孔導(dǎo)度、蒸騰速率、核酮糖-1,5-二磷酸（RuBP）羧化的最大速率（Vcmax）、RuBP再生能力的最大速率（Jmax）均與降水量呈顯著正相關(guān)。通徑分析表明，克氏針茅枯黃期的光合生理機(jī)制因水熱變化的不同而異。當(dāng)前環(huán)境條件下，枯黃期物候變化的主要影響因子是Jmax，主要限制因子是Vcmax。未來(lái)暖干和暖濕氣候下枯黃期物候變化的主要影響因子均是Vcmax；但在暖干氣候下主要限制因子為Jmax，而在暖濕氣候下則無(wú)限制因子。這表明克氏針茅枯黃期物候的變化取決于氣候環(huán)境條件變化對(duì)其光合能力的影響。（周廣勝）

1.27 溫度和光周期協(xié)同作用對(duì)蒙古櫟幼苗春季物候的影響

植物物候?qū)夂蜃兓浅Ｃ舾?，但關(guān)于物候?qū)Σ煌瑲夂蛞蜃訁f(xié)同作用的響應(yīng)機(jī)制仍不清楚。為此，以蒙古櫟為研究對(duì)象，針對(duì)蒙古櫟物候的主要影響因子溫度和光周期，利用大型人工氣候室，模擬研究了溫度與光周期協(xié)同作用（對(duì)照、增溫1.5 ℃、增溫2.0 ℃，不同光周期（10 h、14 h、18 h） 及其協(xié)同作用（對(duì)照處理、增溫1.5 ℃×18 h、增溫1.5 ℃×10 h、增溫2.0 ℃×18 h、增溫2.0 ℃×10 h） ）對(duì)蒙古櫟春季物候的影響與機(jī)制。結(jié)果表明， （1）相同水分條件下，不同升溫程度對(duì)蒙古櫟幼苗春季物候的影響不同。溫升1.5 ℃促進(jìn)蒙古櫟幼苗春季物候（芽膨大期、芽開(kāi)放期、展葉始期和展葉盛期）提前; 而溫升2.0 ℃則對(duì)不同春季物候的影響不同，表現(xiàn)為促進(jìn)芽休眠解除和芽開(kāi)放，但抑制葉片展開(kāi)。（2）相同水分條件下，不同光周期對(duì)蒙古櫟幼苗不同春季物候的影響存在差異。長(zhǎng)光周期對(duì)蒙古櫟幼苗展葉盛期影響最大，短光周期對(duì)芽膨大期影響最大，但均表現(xiàn)為抑制作用。（3）相同水分條件下，溫度升高與光周期增加協(xié)同作用有助于促進(jìn)蒙古櫟幼苗春季物候提前，但溫度升高與光周期縮短協(xié)同作用則對(duì)春季物候有抑制作用。（4）蒙古櫟幼苗春季物候變化與前期氣候脅迫程度存在顯著正相關(guān)，表明前期氣候因子也是物候變化的重要影響因子。研究結(jié)果豐富了蒙古櫟物候響應(yīng)多氣候因子協(xié)同作用的認(rèn)知，有助于促進(jìn)物候模型的完善。（周廣勝）

1.28 1969—2018年金華市舒適度和冷/熱日特征分析

利用1969—2018年氣象觀(guān)測(cè)資料對(duì)金華市年、季尺度的舒適度和冷/熱日數(shù)進(jìn)行分析。結(jié)果表明：金華市全年和各季節(jié)的平均有效溫度均呈顯著上升趨勢(shì)，2000年前后穩(wěn)定超過(guò)平均值且上升趨勢(shì)增加；年均氣候傾向率為0.67 ℃/10a，各季節(jié)的上升趨勢(shì)不同，其中冬季最大，夏季最小。暖冬或冷冬的概率呈先增后減再略增的N型變化趨勢(shì)，熱夏或涼夏的概率呈弱增加趨勢(shì)。舒適期呈雙峰型分布，主要集中在4—6月和9—10月，其中5月的舒適日數(shù)最多。舒適期的50 a平均初、終日分別為4月4日和11月8日，隨時(shí)間推移，初日呈顯著提前趨勢(shì)(約5.7 d/10a)，終日呈顯著延后趨勢(shì)(約4 d/10a)，氣候舒適率總體呈不顯著的弱上升趨勢(shì)。年舒適日數(shù)和熱日數(shù)呈顯著增加趨勢(shì)，分別為5.08 d/10a和2.31 d/10a，冷日數(shù)呈顯著下降趨勢(shì)，達(dá)7.39 d/10a。 整體來(lái)看，金華市冬季氣溫較以往更為溫暖，夏季更熱，春季舒適時(shí)間明顯增多，秋季的冷不舒適體感時(shí)間明顯減少。（周廣勝）

1.29 基于大氣-土壤-植被系統(tǒng)干旱發(fā)生發(fā)展過(guò)程的綜合干旱指標(biāo)構(gòu)建與應(yīng)用

適宜的干旱指標(biāo)和高分辨率數(shù)據(jù)是準(zhǔn)確監(jiān)測(cè)干旱的基礎(chǔ)。本研究從氣象干旱和土壤干旱以及植被對(duì)干旱的響應(yīng)出發(fā)，整合中國(guó)國(guó)家氣象觀(guān)測(cè)站、中國(guó)氣象局陸面數(shù)據(jù)同化系統(tǒng)（CLDAS）土壤濕度0.0625°×0.0625°）和MODIS 葉面積指數(shù)（500 m×500 m）等多源數(shù)據(jù)信息，構(gòu)建了基于氣象干旱指數(shù)（標(biāo)準(zhǔn)化降水蒸散指數(shù)）、土壤干旱指數(shù)（土壤濕度百分位）和植被干旱指數(shù)（葉面積指數(shù)百分位）的綜合干旱指數(shù)，并在中國(guó)東北地區(qū)開(kāi)展了典型站點(diǎn)和區(qū)域10 km×10 km 空間分辨率干旱監(jiān)測(cè)試驗(yàn)。結(jié)果表明，綜合干旱指數(shù)克服了單一氣象干旱指數(shù)不能準(zhǔn)確反映農(nóng)業(yè)旱情及單一植被長(zhǎng)勢(shì)指數(shù)會(huì)將其他災(zāi)害引起的植被長(zhǎng)勢(shì)變差誤判為干旱的不足，能夠反映灌溉對(duì)干旱的影響，實(shí)現(xiàn)對(duì)大氣—土壤—植被系統(tǒng)干旱發(fā)生、發(fā)展及其影響的監(jiān)測(cè)。（周廣勝）

1.30 蒙古櫟展葉盛期變化的光譜特征及其影響因素研究

植物生長(zhǎng)狀況是反映環(huán)境變化的重要指標(biāo)，在全球環(huán)境變化格局下，研究多環(huán)境因子及交互作用對(duì)植物的影響尤為重要。為探究植物光譜特征響應(yīng)環(huán)境變化，從而探究環(huán)境變化對(duì)植物生長(zhǎng)狀況的影響，同時(shí)實(shí)現(xiàn)遙感對(duì)植物的監(jiān)測(cè)，該研究以東北地區(qū)優(yōu)勢(shì)樹(shù)種蒙古櫟為研究對(duì)象，分析研究了不同光周期、溫度和氮沉降交互作用引起的蒙古櫟展葉盛期冠層光譜反射特征變化?；诖笮腿斯夂蚴夷M試驗(yàn)，設(shè)置3個(gè)溫度，3個(gè)光周期和2個(gè)氮沉降交互處理，每個(gè)處理4個(gè)重復(fù)。當(dāng)蒙古櫟進(jìn)入展葉盛期時(shí)，每個(gè)處理選擇差異較小的3個(gè)重復(fù)，使用Fieldspec Pro FR2500型背掛式野外高光譜輻射儀測(cè)量光譜反射率。對(duì)不同處理的蒙古櫟冠層光譜反射率進(jìn)行分析，選取NDVI（歸一化植被指數(shù)）、Chl NDI（歸一化葉綠素指數(shù)）和PRI（光化學(xué)反射指數(shù)）3個(gè)常用的光譜指數(shù)作為輔助分析，同時(shí)計(jì)算一階導(dǎo)數(shù)光譜以得到紅邊斜率、紅邊位置、紅邊面積等參數(shù)。不同處理展葉盛期的蒙古櫟光譜反射率趨勢(shì)大體一致，均符合植物特有的光譜反射特征，在350～680 nm范圍內(nèi)有一個(gè)小的波峰，680～750 nm反射率顯著上升，750 nm后進(jìn)入反射平臺(tái)。結(jié)果表明：（1）光周期對(duì)于蒙古櫟冠層的光譜反射率沒(méi)有明顯的影響；（2）增溫會(huì)減小蒙古櫟冠層在350～750 nm波段處的光譜反射率；（3）施氮會(huì)導(dǎo)致蒙古櫟展葉盛期350～750 nm波段和750～1100 nm波段處的光譜反射率降低；（4）增溫和施氮的交互作用會(huì)顯著減小蒙古櫟的光譜反射率；（5）通過(guò)一階導(dǎo)數(shù)光譜可清晰地指示植物的紅邊特征。研究結(jié)果可為物候變化的監(jiān)測(cè)與影響因素分析提供理論依據(jù)。（周廣勝）

1.31 橫斷山區(qū)地表真實(shí)面積與垂直投影面積差異分析——以雅江縣為例

橫斷山脈地形起伏復(fù)雜，以垂直投影面積作為地表真實(shí)面積進(jìn)行定量計(jì)算會(huì)產(chǎn)生較大誤差。本文以橫斷山脈中部雅江縣為例，基于DEM數(shù)據(jù)和地表覆蓋產(chǎn)品數(shù)據(jù)集，利用地表粗糙度的地學(xué)意義，計(jì)算了雅江縣不同土地利用類(lèi)型地表真實(shí)面積，并分析了地表真實(shí)面積與垂直投影面積之間的差異。結(jié)果表明：雅江縣地表面積與投影面積的差異與DEM分辨率呈正相關(guān)，與海拔呈負(fù)相關(guān)，坡度是地表面積與投影面積差異的主要影響因素，坡度越大，差異越大，差異的增長(zhǎng)速率越大；不同土地利用類(lèi)型對(duì)面積差異有不同程度的影響。（周廣勝）

1.32 不同灌溉量夏玉米葉綠素含量的高光譜特征及其反演

植物葉綠素含量直接影響其光合作用，并與植物的光譜特征密切相關(guān)。以夏玉米為研究對(duì)象，采用人工控水方法研究了夏玉米七葉期不同灌溉量下冠層葉綠素含量特征及其與光譜特征之間的關(guān)系。結(jié)果表明：灌溉量越少，夏玉米葉片葉綠素含量越低，冠層光譜反射率越高，綠峰位置“紅移”，而紅邊位置“藍(lán)移”。葉綠素含量與光譜特征參數(shù)、植被光譜指數(shù)之間存在極顯著相關(guān)關(guān)系，據(jù)此建立了冠層葉綠素含量高光譜估算模型，且基于植被指數(shù)模型較基于單一光譜特征參數(shù)模型模擬效果更好。研究結(jié)果可為夏玉米葉綠素含量的快速無(wú)損測(cè)定以及夏玉米干旱監(jiān)測(cè)提供依據(jù)。（周廣勝）

1.33 中國(guó)毛葡萄和刺葡萄分布的氣候適宜性

毛葡萄和刺葡萄是起源于中國(guó)且用于葡萄酒釀造的兩大野生葡萄品種。本研究基于已有中國(guó)毛葡萄和刺葡萄的氣候影響因子研究成果，利用最大熵原理從充分性與必要性方面確定了影響中國(guó)毛葡萄和刺葡萄種植分布的主導(dǎo)氣候因子，并基于這些因子綜合作用反映的毛葡萄和刺葡萄種植分布的存在概率分析了中國(guó)毛葡萄和刺葡萄分布區(qū)的氣候適宜性。結(jié)果表明，影響中國(guó)毛葡萄、刺葡萄分布的主導(dǎo)氣候因子是年日照時(shí)數(shù)、開(kāi)花期5月降水量、年極端最低氣溫、最冷月平均氣溫。中國(guó)毛葡萄、刺葡萄氣候高適宜區(qū)分布在湖南西部和南部、廣西中北部、貴州東南部、重慶中部。氣候高適宜區(qū)、適宜區(qū)、低適宜區(qū)面積分別占研究區(qū)域總面積的2%、14%和16%。毛葡萄、刺葡萄氣候適宜及以上區(qū)域的年日照時(shí)數(shù)閾值為1200～1800 h，年極端最低氣溫-8 ℃以上，最冷月平均氣溫閾值為2 ～13 ℃，5月降水量為110～320 mm。（周廣勝）

1.34 中國(guó)歐亞種釀酒葡萄種植分布的主要?dú)夂蛴绊懸蜃优c氣候適宜性

開(kāi)展釀酒葡萄氣候適宜性研究對(duì)于優(yōu)化釀酒葡萄布局、氣候資源開(kāi)發(fā)利用具有重要意義?；跉W亞種釀酒葡萄（Vitis vinifera L．）分布數(shù)據(jù)和影響其分布的氣候因子，利用最大熵模型（MaxEnt）和地理信息系統(tǒng)（ArcGIS），研究影響歐亞種釀酒葡萄種植分布的主導(dǎo)氣候因子及其氣候適宜性。結(jié)果表明: MaxEnt 模型能夠很好地模擬我國(guó)歐亞種釀酒葡萄的潛在分布，模擬效果達(dá)到“非常好”（AUC 平均值0.936） 的水平。基于氣候因子對(duì)歐亞種釀酒葡萄地理分布影響的貢獻(xiàn)確定了主導(dǎo)氣候因子，即無(wú)霜期、干燥度、極端最低氣溫、年降水量、生長(zhǎng)季日照時(shí)數(shù)、≥10 ℃活動(dòng)積溫。當(dāng)前，我國(guó)歐亞種釀酒葡萄種植分布的氣候高適宜區(qū)、適宜區(qū)、次適宜區(qū)分別占次適宜及以上區(qū)域總面積的2.9%、20.4%和76.7%。歐亞種釀酒葡萄氣候高適宜區(qū)主要分布在寧夏、山西、陜西、內(nèi)蒙古、山東、河北、新疆、甘肅等省，只考慮氣候因子，陜西、山西、內(nèi)蒙古具有較大的發(fā)展空間。（周廣勝）

1.35 基于微波數(shù)據(jù)與光學(xué)數(shù)據(jù)集成的機(jī)器學(xué)習(xí)技術(shù)在作物產(chǎn)量估算中的應(yīng)用

各類(lèi)光學(xué)植被指數(shù)已成功地應(yīng)用于各種植被監(jiān)測(cè)與作物產(chǎn)量估算中，但這些指數(shù)易受大氣狀況的影響。由星載微波輻射計(jì)得到的植被光學(xué)厚度數(shù)據(jù)（VOD）與植被密度、含水量密切相關(guān)，數(shù)據(jù)可全天候獲得，在農(nóng)業(yè)遙感監(jiān)測(cè)中呈現(xiàn)著巨大的潛力。作為來(lái)自不同傳感器的遙感數(shù)據(jù)，微波遙感數(shù)據(jù)與光學(xué)遙感數(shù)據(jù)可以提供不同波長(zhǎng)范圍內(nèi)的植被信息。為了更準(zhǔn)確地進(jìn)行作物產(chǎn)量估算，本研究提出將微波遙感數(shù)據(jù)與光學(xué)遙感數(shù)據(jù)共同應(yīng)用于冬小麥單產(chǎn)估算中。研究選擇L波段微波輻射計(jì)SMAP衛(wèi)星的VOD數(shù)據(jù)與MODIS的標(biāo)準(zhǔn)歸一化植被指數(shù)NDVI、增強(qiáng)型植被指數(shù)EVI、葉面積指數(shù)LAI、光合有效輻射分量FPAR數(shù)據(jù)作為研究變量，分別使用BP神經(jīng)網(wǎng)絡(luò)、GA-BP神經(jīng)網(wǎng)絡(luò)和PSO-BP神經(jīng)網(wǎng)絡(luò)建立冬小麥產(chǎn)量估算模型。結(jié)果表明，3種神經(jīng)網(wǎng)絡(luò)回歸模型的P值均小于0.001，通過(guò)了顯著性檢驗(yàn)。GA-BP神經(jīng)網(wǎng)絡(luò)回歸模型的估算值與真實(shí)值在3種神經(jīng)網(wǎng)絡(luò)回歸模型中表現(xiàn)了最高的相關(guān)性（R = 0.755）與最低的均方根誤差（RMSE = 529.145 kg/hm2），平均絕對(duì)誤差（MAE = 425.168 kg/hm2）和平均相對(duì)誤差（MRE = 6.530%）。為了分析多源遙感數(shù)據(jù)的結(jié)合在作物產(chǎn)量估算中的優(yōu)勢(shì)，研究同時(shí)構(gòu)建了僅使用NDVI和LAI，使用NDVI、EVI、LAI、FPAR等光學(xué)數(shù)據(jù)進(jìn)行冬小麥產(chǎn)量估算的3種GA-BP神經(jīng)網(wǎng)絡(luò)回歸模型作為對(duì)比。結(jié)果表明，使用微波遙感數(shù)據(jù)與光學(xué)遙感數(shù)建立的GA-BP神經(jīng)網(wǎng)絡(luò)回歸模型較上述3種作為對(duì)比的GA-BP神經(jīng)網(wǎng)絡(luò)回歸模型的相關(guān)系數(shù)R值分別提高了0.163，0.229與0.056，均方根誤差RMSE分別降低了122.334、158.462和46.923 kg/hm2，使用多源遙感數(shù)據(jù)的組合可以很好地提高作物產(chǎn)量估算的準(zhǔn)確性。（房世波）

2 農(nóng)業(yè)氣象

2 Agricultural meteorology

2.1 Integrated remote sensing and crop model approach for impact assessment of aerosols on biomass accumulation of maize

The remote sensing data and crop model were used to explore the dynamic changes and accumulation of maize biomass in China caused by aerosols in this study. Maize varieties were divided into spring maize and summer maize. Two spring maize and three summer maize stations were selected. The results indicated that the solar radiation through all stages of maize development was reduced by aerosols, with daily average reductions of 3.23 MJ m?2d?1for spring maize and 8.96 MJ m?2d?1for summer maize from 2001 to 2014.Aerosols reduced the daily actual maize biomass in the study area, with an average daily decrease of 3.78 g m?2d?1from 2001 to 2014. Moreover, the changes in daily actual biomass caused by aerosols varied in different growth stages. The reduction in daily actual biomass caused by aerosols in the stage of emergence?flowering was larger than that in the stage of flowering?maturity. For spring maize, the changes in daily actual biomass caused by aerosols were –2.12 to –2.29 g m?2d?1from emergence to flowering and ?0.72 to 0.08 g m?2d?1from flowering to maturity. For summer maize, the changes in daily actual biomass caused by aerosols were–8.94 to –3.45 g m?2d?1from emergence to flowering and ?6.50 to ?2.24 g m?2d?1from flowering to maturity.In addition, the annual maize biomass from 2001 to 2014 at five stations clearly decreased owing to aerosols.Moreover, the decrease in the annual biomass of summer maize was greater than that of spring maize, with an average decrease of 27.77% in summer maize biomass and 10.94% in spring maize biomass. ( Zhao Junfang)

2.2 Long-term variations in solar radiation, diffuse radiation, and diffuse radiation fraction caused by aerosols in China during 1961–2016

The effects of atmospheric aerosols on the terrestrial climate system are more regional than those of greenhouse gases, which are more global. Thus, it is necessary to examine the typical regional effects of how aerosols affect solar radiation in order to develop a more comprehensive understanding. In this study, we used global AErosol RObotic NETwork (AERONET) data and robust radiation observational evidence to investigate the impact of aerosols on total radiation, diffuse radiation, and the diffuse radiation fraction in China from 1961 to 2016. Our results showed that there were different temporal changes in the aerosol optical depth (AOD),total solar radiation, diffuse radiation, and diffuse radiation fraction over the past 56 years. Specifically, the 550 nm AOD from 2005 to 2016 decreased significantly, with annual average AOD of 0.51. Meanwhile, the average total solar radiation reduced by 2.48%, while there was a slight increase in average diffuse radiation at a rate of 3.10 MJ m?2yr?1. Moreover, the spatial heterogeneities of AOD, total radiation, diffuse radiation,and the diffuse radiation fraction in China were significant. Aerosol particle emissions in the developed eastern and southern regions of China were more severe than those in the western regions, resulting in higher total radiation and diffuse radiation in the western plateau than in the eastern plain. In addition, aerosols were found to have negative effects on total radiation and sunshine hours, and positive effects on diffuse radiation and diffuse radiation fraction. Further, the diffuse radiation fraction was negatively correlated with sunshine hours.However, there was a positive correlation between AOD and sunshine hours. These results could be used to assess the impacts of climate change on terrestrial ecosystem productivity and carbon budgets. ( Zhao Junfang)

2.3 Assessment of seasonal variability of extreme temperature in mainland China under climate change

Some studies have suggested that variations in the seasonal cycle of temperature and season onset could affect the efficiency in the use of radiation by plants, which would then affect yield. However, the study of the temporal variation in extreme climatic variables is not sufficient in China. Using seasonal trend analysis (STA),this article evaluates the distribution of extreme temperature seasonality trends in mainland China, describes the trends in the seasonal cycle, and detects changes in extreme temperature characterized by the number of hot days (HD) and frost days (FD), the frequency of warm days (TX90p), cold days (TX10p), warm nights(TN90p), and cold nights (TN10p). The results show a statistically significant positive trend in the annual average amplitudes of extreme temperatures. The amplitude and phase of the annual cycle experience less variation than that of the annual average amplitude for extreme temperatures. The phase of the annual cycle in maximum temperature mainly shows a significant negative trend, accounting for approximately 30% of the total area of China, which is distributed across the regions except for northeast and southwest. The amplitude of the annual cycle indicates that the minimum temperature underwent slightly greater variation than the maximum temperature, and its distribution has a spatial characteristic that is almost bounded by the 400 mm isohyet, increasing in the northwest and decreasing in the southeast. In terms of the extreme air temperature indices, HD, TX90p, and TN90p show an increasing trend, FD, TX10p, and TN10p show a decreasing trend.They are statistically significant (p < 0.05). This number of days also suggests that temperature has increased over mainland China in the past 42 years. ( Zhao Junfang)

2.4 Indicator-based spatiotemporal characteristics of apple drought in North China

Frequent occurrences of drought stress caused by dry weather create severe destroy in apple yield and quality in North China. Although appropriate drought stress is beneficial to apple planting, it might change to apple drought disaster when dry weather continues and reaches to a certain magnitude. So, precisely identification of apple drought based on weather condition is of great merit to provide a basis for targeted apple drought monitoring, early warning and evaluation. To explore the trigger dry weather condition of an apple drought event, apple drought index (ADI) was firstly constructed by the consideration of physiological water demand and precipitation characteristics. The ADIs in historical apple drought disaster samples were reanalysed in North China, and the distribution-type fitting and confidence interval method were used to identify the drought trigger thresholds in the apple drought indicators. Afterwards, spatiotemporal characteristics of apple drought in North China from 1981 to 2018 were explored based on the apple drought indicators. Drought trigger thresholds were ADI 0.86, 0.84 and 0.76 for apple tree germinating to bud brush (P1), bud brush to flowering (P2) and flowering to maturity (P3), respectively. A percentage of 81.82% of drought indicatorbased results were strongly consistent with historical records about apple drought disasters. Indicator-based regional average apple drought ratios in North China from 1981 to 2018 were 28.27%, 28.33% and 20.82% in P1, P2 and P3, respectively. 2009, 2000 and 2001 were detected the highest drought frequency years for P1,P2 and P3, with drought ratio 57.07%, 60.00% and 40.98%, respectively. The results can provide technical and theoretical support for targeted apple drought detection, and information and measures for apple drought prevention and mitigation can be implemented according to the indicator-based results. (Yang Jianying)

2.5 Process-based indicators for timely identification of apricot frost disaster on the warm temperate zone, China

Frequent occurrences of late spring frost disaster create severe agricultural/forest damage, even given the background of global warming. In the warm temperate zone of China, which is the largest planting area for fresh apricot, late spring frost disaster has become one of the major meteorological hazards during flowering.To prevent cold weather-induced apricot frost disaster and reduce potential losses in related fruit economic value, it is vital to establish a meteorological indicator for timely and accurate identification of cold weather process-based apricot frost disaster, to provide support for timely apricot frost monitoring and warning in late spring. In this study, daily minimax temperature (Tmin) and apricot frost disaster data during flowering were combined to establish meteorological identification indicators of apricot frost based on cold weather processes.A process-based apricot frost model f (D,T Tcum) was firstly constructed, and characteristics of Tcum(accumulated harmful temperature) were explored under different D (duration days) based on the representation of historical apricot frost processes. Thresholds for the Tcumfor apricot frost in 1, 2, 3, 4 and more than 5 days of apricot frost process were determined as ?1.5, ?2.9, ?4.4, ?5.8 and ?7.3 °C, respectively. Validation results by reserved independent disaster samples were generally consistent with the historical records of apricot frost disasters,with 89.00% accuracy for indicator-based identification results. Typical process tracking of the proposed identification indicator to an apricot frost event that occurred in North Hebei during April 3?9, 2018 revealed that the indicator-based identification result basically coincides with the historical disaster record and can reflect more detailed information about the apricot frost process. (Yang Jianying)

2.6 Threshold-based characteristics of apricot frost exposure at young fruit in the warm temperate zone, China

Late spring frost stress is one of the major environmental limiting factors for apricot in the warm zoon in China. Investigation of frost exposure of apricot is of particular interest for estimating the frost risk, thus representing the potential damage for apricot production. In this study, daily minimum temperature (Tmin),disaster and phenological data of apricot from 1981 to 2020 in the warm zoon were integrated to explore the temperature threshold on apricot at young fruit, facilitating the assessment of apricot frost exposure under the background of climate warming. The daily Tminwas firstly extracted according to the historical disaster records,to identify the per- and ongoing weather conditions of the low-temperature events. The overall accuracy and receiver operating characteristics curve (ROC) were combined to identify the trigger threshold of apricot frost.The temperature of 1.9 was identified as the apricot frost trigger threshold in regional assessment, with relatively higher correct rate for disaster (90.2%) and lower incorrect rate for none-disaster (23.4%). An area under the ROC curve (AUC) of 0.88 was obtained, demonstrating a good performance of Tminas the trigger factor in discriminating between apricot frost and no frost. High frequency of days suffered from apricot and frost exposure (E) at young fruit were mainly found in the northwestern and middle parts of the region, with frequencies of more than 2 days and E more than 3. Regional days suffered from apricot frost and E were found to have a negative trend with slope ?0.0317 and ?0.789, respectively, whereas the northwest and middle part of the study region were found to have an increasing trend. The results can provide technical and theoretical support for targeted apricot frost detection and risk assessment, and measures for apricot frost prevention and mitigation can be implemented according to the threshold-based results. (Yang Jianying)

2.7 Dryland maize yield potentials and constraints: A case study in western Kansas

Water-limited environments account for half of the earth’s land surface and dryland agriculture acreage is projected to expand due to climate changes. Examining typical dryland yield potentials and yield improvement measures is crucial for developing future dryland crop production systems. This case study used crop modeling to analyze dryland maize yield potential (YPd), farmers’ yield potential (YPf), and actual farm yields (Ya)in 1990?2015 in three counties in western Kansas (i.e., Thomas, Greeley and Finney in the U.S. Great Plains region). The calibrated APSIM-Maize model along with actual yields was used to estimate yield gaps attributed to: (1) agronomic factors (YG1 = YPd ? YPf) and, (2) socio-economic constraints (YG2 = YPf ? Ya).Observed climate conditions during maize growing seasons showed warming, brightening, and drying trends for all three counties in western Kansas from 1990 to 2015. Our results showed that the current actual farm yields (Ya) in western Kansas represented only 34%, 32%, and 28% of YPd in Thomas, Greeley, and Finney counties respectively, indicating significant exploitable yield gaps. Agronomic factors (YG1) contributed the greatest to the yield gap in Greeley and Finney counties whereas socioeconomic constraints (YG2) offered the greatest opportunity for improvement in Thomas county. Our analysis suggested that improving agronomic management could be a greater priority for further yield improvement in Greeley county but selecting an appropriate hybrid was a greater priority in Finney county. (Sun Shuang)

2.8 Standardized relative humidity index can be used to identify agricultural drought for summer maize in the Huang-Huai-Hai Plain, China

Maize (Zea mays L.) is a staple food in most parts of the world, and is also one of the most important food crops in China. Frequent occurrences of drought events can lead to summer maize drought disasters. The air relative humidity has the predominant superiority in spatio-temporal continuity compared to precipitation.In this study, meteorological data, phenophase observations, and disaster records of summer maize in the Huang-Huai-Hai Plain (the HHH Plain) were jointly used to establish a standardized relative humidity index(SRHI) to identify and characterize summer maize drought disasters and to provide support for summer maize drought monitoring, prevention, and mitigation. Results showed that the threshold values of SRHI10 (at tenday scale) during the V0-VT (planting-tasseling) and VT-R6 (tasseling-physiological maturity) periods were?0.05 and ?0.25, and the values of SRHI30 (at monthly scale) during the V0-VT and VT-R6 periods were ?0.10 and ?0.50, respectively. Both SRHI10 and SRHI30 could reasonably identify the actual drought conditions of summer maize in the HHH Plain. Validation with independent drought samples showed that SRHI10 was the most effective among SRHI10, SRHI30, and SPI10. The province-wide validation within 55 years also revealed that the drought of summer maize identified with SRHI10 was basically consistent with historical disaster records, with the average identification accuracy being of 94.0%. Additionally, SRHI10 could indicate the occurrence of drought relatively earlier than actual drought records during both the V0-VT and VT-R6 periods of summer maize. Therefore, the spatio-temporal distribution characteristics of drought for summer maize in the HHH Plain were mapped based on SRHI10. Drought occurred in 38% and 25% of the years during the V0-VT and VT-R6 periods, respectively, from 1961 to 2015. The drought extent during the V0-VT period was greater than that during the VT-R6 period in 64% of the study years, indicating that summer maize in the HHH Plain was more exposed to drought during the vegetative growth period. The spatial distribution pattern of drought severity increased from the south to north during the V0-VT period, while during the VTR6 period it exhibited the same spatial pattern to drought frequency. The drought in both the V0-VT and VTR6 periods of summer maize showed the increasing trend in most of the HHH Plain of China. SRHI10 can be a useful indicator for monitoring and assessing summer maize drought disasters at regional scale. This index can also provide a new method for agricultural drought analysis. (Wang Peijuan )

2.9 Spring frost damage to tea plants can be identified with daily minimum air temperatures estimated by MODIS land sur-face temperature products

Tea (Camellia sinensis) is one of the most dominant economic plants in China and plays an important role in agricultural economic benefits. Spring tea is the most popular drink due to Chinese drinking habits.Although the global temperature is generally warming, spring frost damage (SFD) to tea plants still occurs from time to time, and severely restricts the production and quality of spring tea. Therefore, monitoring and evaluating the impact of SFD on tea plants in a timely and precise manner is a significant and urgent task for scientists and tea producers in China. The region designated as the middle and lower reaches of the Yangtze River (MLRYR) in China is a major tea plantation area producing small tea leaves and low shrubs.This region was selected to study SFD to tea plants using meteorological observations and remotely sensed products. Comparative analysis between minimum air temperature (Tmin) and two MODIS nighttime land surface temperature (LST) products at six pixel-window scales was used to determine the best suitable product and spatial scale. Results showed that the LST nighttime product derived from MYD11A1 data at the 3×3 pixel window resolution was the best proxy for daily minimum air temperature. A Tminestimation model was established using this dataset and digital elevation model (DEM) data, employing the standard lapse rate of air temperature with elevation. Model validation with 145210 ground-based Tminobservations showed that the accuracy of estimated Tminwas acceptable with a relatively high coefficient of determination (R2=0.841), low root mean square error (RMSE=2.15 °C) and mean absolute error (MAE=1.66 °C), and reasonable normalized RMSE (NRMSE=25.4%) and Nash-Sutcliffe model efficiency (EF=0.12), with significantly improved consistency of LST and Tminestimation. Based on the Tminestimation model, three major cooling episodes recorded in the “Yearbook of Meteorological Disasters in China” in spring 2006 were accurately identified, and several highlighted regions in the first two cooling episodes were also precisely captured. This study confirmed that estimating Tminbased on MYD11A1 nighttime products and DEM is a useful method for monitoring and evaluating SFD to tea plants in the MLRYR. Furthermore, this method precisely identified the spatial characteristics and distribution of SFD and will therefore be helpful for taking effective preventative measures to mitigate the economic losses resulting from frost damage. (Wang Peijuan )

2.10 Mapping threats of spring frost damage to tea plants using satellite-based minimum temperature estimation in China

Spring frost damage (SFD), defined as the disaster during the period of newly formed tea buds in spring caused by lower temperature and frost damage, is a particular challenge for tea plants (Camellia sinensis),whose capacity to adapt to extreme weather and climate impacts is limited. In this paper, the region of the middle and lower reaches of the Yangtze River (MLRYR) in China was selected as the major tea plantation study area, and the study period was focused on the concentrated occurrence of SFD, i.e., from March to April. By employing the standard lapse rate of air temperature with elevation, a minimum temperature (Tmin)estimation model that had been previously established was used based on reconstructed MYD11A1 nighttime LST values for 3×3 pixel windows and digital elevation model data. Combined with satellite-based Tminestimates and ground-based Tminobservations, the spatiotemporal characteristics of SFD for tea plants were systematically analyzed from 2003 to 2020 in the MLRYR. The SFD risks at three scales (temporal, spatial,and terrain) were then evaluated for tea plants over the MLRYR. The results show that both SFD days at the annual scale and SFD areas at the daily scale exhibited a decreasing trend at a rate of 2.7 days decade?1and 2.45×104ha day?1, respectively (significant rates at the 0.05 and 0.01 levels, respectively). The period with the highest SFD risk appeared mainly in the first twenty days of March. However, more attention should be given to the mid-to-late April time period due to the occurrence of late SFD from time to time. Spatially, areas with relatively higher SFD days and SFD risks were predominantly concentrated in the higher altitude areas of northwestern parts of MLRYR for both multi-year averages and individual years. Fortunately, in regions with a higher risk of SFD, the distribution of tea plants was relatively scattered and the area was small. These findings will provide helpful guidance for all kinds of people, including government agencies, agricultural insurance agencies, and tea farmers, in order that reasonable and effective strategies to reduce losses caused by spring frost damage to tea plants may be recommended and implemented. (Wang Peijuan )

2.11 GHCN-CAMS和CMFD兩種尺度再分析資料對(duì)寧夏氣溫反映能力評(píng)估

再分析資料能有效彌補(bǔ)實(shí)際觀(guān)測(cè)數(shù)據(jù)時(shí)空分布不均的缺陷，開(kāi)展再分析資料區(qū)域適應(yīng)性評(píng)估對(duì)地氣過(guò)程研究、氣候分析等具有重要意義。論文利用寧夏24 個(gè)氣象觀(guān)測(cè)站的平均氣溫，從2種空間尺度（0.5°×0.5°和0.1°×0.1°）和2種時(shí)間尺度（年、月），采用偏差、絕對(duì)偏差、均方根誤差和相關(guān)系數(shù)等多個(gè)統(tǒng)計(jì)指標(biāo)，評(píng)估了再分析資料對(duì)寧夏地區(qū)地面氣溫的反映能力。結(jié)果表明：（1）GHCNCAMS（Global Historical Climatology Network and the Climate Anomaly Monitoring System）和CMFD（China Meteorological Forcing Dataset）2 套再分析資料對(duì)寧夏氣溫的反映能力整體上均較強(qiáng)，前者對(duì)寧夏氣溫略高估，后者略低估。（2）年和月2種時(shí)間尺度上，2種尺度的再分析資料存在階段性正偏差和負(fù)偏差，且年尺度上的相關(guān)性好于月尺度的。（3）2套再分析資料對(duì)下墊面主要為農(nóng)田(壓砂種植)的氣溫均存在冷季高估、暖季低估的情況，對(duì)城鎮(zhèn)兩者總體均低估，對(duì)草地整體表現(xiàn)為CMFD 在冷季低估、暖季略高估，而GHCN-CAMS在冷季高估、暖季低估。總體看，空間分辨率較高的CMFD再分析資料對(duì)寧夏氣溫的反映能力更好一些。(趙俊芳)

2.12 作物發(fā)育模式重構(gòu)及基于甘蔗的模擬檢驗(yàn)

發(fā)育進(jìn)程是作物的生理年齡， 發(fā)育模式是作物生長(zhǎng)模型的時(shí)間指針。 但目前的發(fā)育模式只關(guān)注某時(shí)段（日）氣象條件對(duì)作物發(fā)育的影響，其準(zhǔn)確率也難以滿(mǎn)足作物生長(zhǎng)模擬的需求。 根據(jù)作物發(fā)育速率不僅與氣象條件有關(guān)、還與其所處發(fā)育期有關(guān)的理論假設(shè)， 重構(gòu)發(fā)育進(jìn)程模式， 并利用1980—2019年我國(guó)甘蔗發(fā)育實(shí)測(cè)數(shù)據(jù)進(jìn)行模式適應(yīng)性分析， 比較傳統(tǒng)模式與重構(gòu)模式的模擬能力。 結(jié)果表明：重構(gòu)模式中，發(fā)育單位日序模式和溫度日序模式對(duì)甘蔗發(fā)育進(jìn)程的適應(yīng)性均較好， 尤其在后期溫度不斷降低的發(fā)育進(jìn)程以及低溫年型的模擬中， 其適應(yīng)能力明顯優(yōu)于傳統(tǒng)模式。 重構(gòu)及傳統(tǒng)模式模擬能力從強(qiáng)到弱依次為發(fā)育單位日序模式、 溫度日序模式、 響應(yīng)適應(yīng)模式、 發(fā)育單位模式、 發(fā)育單位溫度修正模式、 熱量單位模式， 均方根誤差計(jì)算的模擬能力值依次為4.3、3.9、3.7、3.3、3.0、2.8。（馬玉平）

2.13 中國(guó)普通油茶種植氣候適宜性區(qū)劃

發(fā)展油茶產(chǎn)業(yè)可有效增加農(nóng)民收益，促進(jìn)精準(zhǔn)扶貧并改善生態(tài)環(huán)境。對(duì)油茶進(jìn)行全國(guó)尺度的氣候適宜性區(qū)劃，可以為油茶產(chǎn)業(yè)的發(fā)展提供科學(xué)依據(jù)。本研究以中國(guó)分布面積最廣、產(chǎn)量最高的普通油茶為對(duì)象，選擇年平均氣溫、1月和7月平均氣溫、年降水量和日照時(shí)數(shù)為關(guān)鍵氣候因子，計(jì)算主產(chǎn)區(qū)（即種植面積在6667 hm2以上的縣市） 的關(guān)鍵因子值?；谶@些因子值，采用改進(jìn)的氣候相似距法進(jìn)行全國(guó)1 km×1 km網(wǎng)格的普通油茶種植氣候適宜性區(qū)劃。結(jié)果表明：中國(guó)普通油茶的最適宜區(qū)面積為98×104km2，主要分布在湖南、江西、福建和浙江四省及周?chē)〉南噜弲^(qū)域；適宜區(qū)面積和次適宜區(qū)分別為52×104km2和80×104km2，依次分布在最適宜區(qū)的外圍；次適宜區(qū)北界約為北緯33.5°，西界約為東經(jīng)111.5°，南界和東界不明顯；湖南省的最適宜區(qū)面積最大，其次是江西、廣西、浙江和福建，五省合計(jì)約占全國(guó)最適宜區(qū)面積的70%；與多種來(lái)源實(shí)際種植面積資料對(duì)比表明，區(qū)劃較好地反映了普通油茶的種植狀況；與主產(chǎn)區(qū)氣候特征對(duì)比表明，區(qū)劃較為準(zhǔn)確地區(qū)分了普通油茶最適宜區(qū)、適宜區(qū)和次適宜區(qū)的氣候特征。本研究明確了普通油茶種植氣候適宜區(qū)的分布，可為油茶產(chǎn)業(yè)的規(guī)劃布局提供科學(xué)支撐。(鄔定榮)

2.14 中國(guó)電線(xiàn)積冰災(zāi)害研究進(jìn)展

電線(xiàn)積冰災(zāi)害是導(dǎo)致電力系統(tǒng)發(fā)生事故的重要自然災(zāi)害之一?；谝延醒芯砍晒?，從電線(xiàn)積冰相關(guān)概念與分類(lèi)出發(fā)，對(duì)電線(xiàn)積冰的影響與危害、時(shí)空分布、成因、影響因子、預(yù)報(bào)模型、風(fēng)險(xiǎn)評(píng)估以及預(yù)防措施等方面進(jìn)行歸納。我國(guó)電線(xiàn)積冰災(zāi)害以霧凇型積冰和雨凇型積冰為主，主要環(huán)境成因包括準(zhǔn)靜止鋒、大氣垂直結(jié)構(gòu)和逆溫層，同時(shí)還受到地形、高度和導(dǎo)線(xiàn)自身特性等的影響。電線(xiàn)積冰災(zāi)害總體上呈現(xiàn)北方多霧凇而南方多雨凇的分布特征，20世紀(jì)80—90年代的積冰日數(shù)較多，90年代后呈下降趨勢(shì)。為更好地實(shí)現(xiàn)電線(xiàn)積冰災(zāi)害的模擬與預(yù)測(cè)，預(yù)報(bào)模型也在不斷完善，包括物理數(shù)值模型和統(tǒng)計(jì)預(yù)測(cè)模型；而對(duì)于電線(xiàn)積冰災(zāi)害風(fēng)險(xiǎn)評(píng)估的研究較少，主要集中在電線(xiàn)積冰災(zāi)害的危險(xiǎn)性和線(xiàn)路的脆弱性?；诙鄬W(xué)科指標(biāo)構(gòu)建的電線(xiàn)積冰綜合性指標(biāo)、基于災(zāi)變過(guò)程的綜合風(fēng)險(xiǎn)評(píng)估及氣候變化對(duì)電線(xiàn)積冰的影響將是今后重點(diǎn)研究方向。（霍治國(guó)）

2.15 中國(guó)北方冬小麥蚜蟲(chóng)氣候風(fēng)險(xiǎn)評(píng)估

基于1958—2018年中國(guó)北方冬小麥主產(chǎn)區(qū)8個(gè)主產(chǎn)?。ㄊ校┬←溠料x(chóng)發(fā)生面積、防治面積和小麥播種面積、產(chǎn)量損失、561個(gè)氣象站點(diǎn)逐日氣象資料和典型農(nóng)業(yè)氣象站小麥發(fā)育期資料，采用相關(guān)分析、主成分分析和回歸分析等方法，構(gòu)建華北、黃淮及蘇皖地區(qū)小麥蚜蟲(chóng)分區(qū)域的氣候致災(zāi)指數(shù)。以小麥蚜蟲(chóng)年代際氣候致災(zāi)指數(shù)所劃分不同致災(zāi)等級(jí)發(fā)生頻次作為小麥蚜蟲(chóng)氣候危險(xiǎn)性指標(biāo)，采用小麥蚜蟲(chóng)發(fā)生面積率作為脆弱性指標(biāo)，防治面積與發(fā)生面積比值作為防災(zāi)減災(zāi)能力指標(biāo)，綜合評(píng)估小麥蚜蟲(chóng)氣候風(fēng)險(xiǎn)趨勢(shì)。結(jié)果表明：北方冬小麥主產(chǎn)區(qū)小麥蚜蟲(chóng)氣候危險(xiǎn)性呈增加態(tài)勢(shì)，年代際差異明顯；小麥蚜蟲(chóng)發(fā)生脆弱性隨年代變化也呈逐步加重態(tài)勢(shì)；小麥蚜蟲(chóng)防災(zāi)減災(zāi)能力總體呈逐步增強(qiáng)趨勢(shì)，20世紀(jì)90年代提升顯著；90年代起小麥蚜蟲(chóng)氣候風(fēng)險(xiǎn)逐步加重，高風(fēng)險(xiǎn)范圍逐漸擴(kuò)大，華北、黃淮分別于21世紀(jì)初、2011—2018年風(fēng)險(xiǎn)等級(jí)達(dá)最高；小麥蚜蟲(chóng)氣候風(fēng)險(xiǎn)高的區(qū)域主要分布在北京、天津、河北中南部大部、山東北部部分地區(qū)，較高區(qū)域分布在山東大部、河南北部等地。（霍治國(guó)）

2.16 季節(jié)性?xún)鐾恋姆植寂c變化特征及對(duì)多樣性農(nóng)區(qū)農(nóng)業(yè)生產(chǎn)的影響

研究季節(jié)性?xún)鐾恋姆植寂c變化對(duì)多樣性農(nóng)區(qū)農(nóng)業(yè)生產(chǎn)的影響，對(duì)于合理利用氣候資源，指導(dǎo)當(dāng)?shù)剞r(nóng)業(yè)生產(chǎn)具有重要的意義。文章以臨汾市為例，選用1960—2019年臨汾市17個(gè)觀(guān)測(cè)站逐日的凍土深度、溫度、地溫、降水量和蒸發(fā)量等資料數(shù)據(jù)，采用克里金空間插值法分析研究區(qū)凍土的空間分布，并運(yùn)用M-K檢驗(yàn)、一元線(xiàn)性回歸、相關(guān)分析等方法分析研究區(qū)不同海拔高度季節(jié)性?xún)鐾恋淖兓厔?shì)及影響因素。（1）臨汾市季節(jié)性?xún)鐾辽疃仍谏絽^(qū)大于盆地，北部大于南部，凍土深度與海拔高度正相關(guān)顯著，相關(guān)系數(shù)為0.712 （P＜0.01）具有明顯的垂直分布特征。（2）近年來(lái)最大凍土深度呈明顯下降趨勢(shì)，變化傾向率平均為-2.304 cm/10a，高海拔地區(qū)變化趨勢(shì)尤為顯著，1982年凍土深度發(fā)生突變，突變后從一個(gè)相對(duì)偏深期躍變?yōu)橄鄬?duì)較淺期。（3）凍土始凍日山區(qū)早于平川，北部早于南部，解凍日剛好相反，凍土持續(xù)期平均相差1個(gè)月左右；多年來(lái)臨汾市土壤表面始凍日推遲，解凍日提前，凍土期明顯減少，平均變化率分別為2.088 d/10a、1.762 d/10a和4.069 d/10a，低海拔地區(qū)變化趨勢(shì)更為明顯。（4）相關(guān)分析表明，凍土深度受冬季地面最低氣溫影響極顯著，其中1月的地面最低氣溫升高對(duì)凍土深度變化起到主要的促進(jìn)作用，這種影響在高海拔地區(qū)更為明顯；春、秋兩季的地面最低氣溫升高，使研究區(qū)始凍日推遲，解凍日提前，相關(guān)系數(shù)分別為-0.741、-0.408（P＜0.01），凍土期明顯縮短，蒸發(fā)量的相對(duì)減少對(duì)凍土期和凍土深度變化起到一定抑制作用，降水量對(duì)凍土期和凍土深度影響甚微。臨汾市凍土期縮短，凍土深度變淺，使越冬農(nóng)作物干旱加劇，病蟲(chóng)害發(fā)生幾率增加，同時(shí)增加了植物安全越冬系數(shù)，使作物生長(zhǎng)季延長(zhǎng)，對(duì)農(nóng)業(yè)增產(chǎn)起到一定作用。（霍治國(guó)）

2.17 山西省干旱災(zāi)害風(fēng)險(xiǎn)評(píng)估與區(qū)劃

分析山西省干旱災(zāi)害風(fēng)險(xiǎn)的關(guān)鍵作用因子，并進(jìn)行風(fēng)險(xiǎn)評(píng)估和區(qū)劃，對(duì)于提升該地干旱災(zāi)害風(fēng)險(xiǎn)管理和決策水平、減輕干旱損失具有重要指導(dǎo)意義。文章利用改進(jìn)的相對(duì)濕潤(rùn)度指數(shù)、DEM資料、地形坡度資料和1990—2016年以縣（市）為單元的行政區(qū)域的人口密度、GDP、人均GDP、耕地面積等社會(huì)經(jīng)濟(jì)數(shù)據(jù)來(lái)定量化評(píng)價(jià)山西干旱風(fēng)險(xiǎn)，從干旱災(zāi)害致災(zāi)因子的危險(xiǎn)性、孕災(zāi)環(huán)境的脆弱性、承災(zāi)體的易損性和防災(zāi)減災(zāi)能力4個(gè)方面選取因子，構(gòu)建相應(yīng)的指數(shù)模型并分析其空間分布狀況，在此基礎(chǔ)上進(jìn)一步構(gòu)建山西省干旱災(zāi)害風(fēng)險(xiǎn)綜合評(píng)估模型，并基于GIS 繪制山西省干旱災(zāi)害風(fēng)險(xiǎn)區(qū)劃圖。山西省干旱致災(zāi)因子危險(xiǎn)性呈北高南低的趨勢(shì)，大同、朔州、忻州北部和西部、太原南部的干旱致災(zāi)因子危險(xiǎn)性最強(qiáng)；孕災(zāi)環(huán)境脆弱性呈東西兩側(cè)高、中間低的趨勢(shì)，而承災(zāi)體易損性和防災(zāi)減災(zāi)能力均呈東西兩側(cè)低、中間高的趨勢(shì)；從干旱災(zāi)害風(fēng)險(xiǎn)區(qū)劃圖可以看出，山西省干旱風(fēng)險(xiǎn)總體呈北高南低，從西北向東南遞減的趨勢(shì)。高風(fēng)險(xiǎn)區(qū)主要分布在大同、朔州東部，較高風(fēng)險(xiǎn)區(qū)包括朔州西部、忻州中西部、太原大部，呂梁大部、晉中西部、臨汾中部、運(yùn)城西部為中風(fēng)險(xiǎn)區(qū)，臨汾西部、晉中大部、長(zhǎng)治東北部為較低風(fēng)險(xiǎn)區(qū)，臨汾東部、運(yùn)城東部、晉城大部、長(zhǎng)治西部和南部風(fēng)險(xiǎn)最低。山西省干旱災(zāi)害的精細(xì)化風(fēng)險(xiǎn)區(qū)劃，可為相關(guān)區(qū)域有效地開(kāi)展抗旱活動(dòng)提供定量化依據(jù)，增強(qiáng)干旱災(zāi)害防御的科學(xué)性、實(shí)用性和可操作性。（霍治國(guó)）

2.18 山西省主要糧食作物氣候資源利用率評(píng)估

分析和評(píng)價(jià)區(qū)域農(nóng)業(yè)氣候資源狀況，找出影響農(nóng)業(yè)氣候資源有效匹配的限制因子，提高農(nóng)業(yè)氣候資源利用率，對(duì)促進(jìn)農(nóng)業(yè)生產(chǎn)、提升農(nóng)業(yè)產(chǎn)能具有重要的實(shí)踐意義。本文基于山西省1981—2018 年108 個(gè)地面氣象觀(guān)測(cè)站的逐日氣溫、降水、日照等氣象資料及31個(gè)農(nóng)業(yè)氣象觀(guān)測(cè)站春玉米、夏玉米和冬小麥的發(fā)育期觀(guān)測(cè)資料，采用平均資源適宜指數(shù)、平均效能適宜指數(shù)和平均資源利用指數(shù)分析了山西省不同作物種植區(qū)的氣候資源適宜程度、匹配狀況和利用率，結(jié)果表明：（1）山西省春玉米種植區(qū)大部氣候資源適宜程度、匹配程度和利用率均較高，西部呈增加趨勢(shì)、中東部大部呈降低趨勢(shì)；朔州和忻州中西部溫度偏低，制約了該區(qū)域光、溫、水的合理匹配，利用率較低。（2） 山西省夏玉米種植區(qū)氣候資源適宜度較高，但匹配一般，尤其是運(yùn)城中西部受降水偏少的影響，氣候資源利用率相對(duì)較低；全區(qū)大部夏玉米氣候資源適宜程度、匹配狀況及利用率均呈下降趨勢(shì)。（3） 山西省冬小麥種植區(qū)平均資源適宜指數(shù)、平均效能適宜指數(shù)和平均資源利用指數(shù)均呈西北低、東南高的空間分布格局，西北部降水偏少導(dǎo)致光、溫、水匹配不佳，利用率較低，長(zhǎng)治、晉城、臨汾中部和運(yùn)城東部等地資源利用率呈上升趨勢(shì)，呂梁、太原、晉中和運(yùn)城西部等地呈下降趨勢(shì)。由此可見(jiàn)，晉北地區(qū)提高農(nóng)業(yè)氣候資源利用率的有效途徑重點(diǎn)是提升熱量資源的利用率，晉中盆地區(qū)域以提高水資源利用率為主，晉南運(yùn)城及臨汾盆地區(qū)域除提升水資源利用率外，還需考慮溫度持續(xù)增高對(duì)作物生長(zhǎng)發(fā)育帶來(lái)的不利影響。（郭建平）

2.19 中國(guó)主產(chǎn)區(qū)玉米冠層對(duì)降水的截留研究

基于13個(gè)農(nóng)業(yè)氣象試驗(yàn)站2010—2017年逐日氣象觀(guān)測(cè)數(shù)據(jù)和玉米觀(guān)測(cè)數(shù)據(jù)，采用針對(duì)玉米的截留模型，研究自然降雨條件下中國(guó)主產(chǎn)區(qū)玉米冠層截留及其變化規(guī)律。結(jié)果表明：在不同氣候條件和生長(zhǎng)狀況下，玉米全生育期冠層截留差異較大。玉米冠層生長(zhǎng)季平均截留量為4.3～23.5 mm，拔節(jié)到成熟期降水量≤70 mm時(shí)，截留量不足8 mm，隨著降水量增加，截留量先是同時(shí)受降水量和最大面積指數(shù)制衡，后變?yōu)閷?duì)最大葉面積指數(shù)更敏感。平均截留率為1.9%～11.6%，中國(guó)四大玉米主產(chǎn)區(qū)中的黃淮海夏播玉米區(qū)截留率最穩(wěn)定，生長(zhǎng)季降水量＜120 mm的地區(qū)截留率超過(guò)10%，按玉米主產(chǎn)區(qū)和氣候干濕度兩種分類(lèi)提供平均截留率范圍。依據(jù)拔節(jié)到成熟期降水量、最大葉面積指數(shù)及截留變化規(guī)律可以估算不同地區(qū)玉米冠層截留量和截留率，為有效降水評(píng)估、干旱指標(biāo)修正、農(nóng)田水分循環(huán)等方面提供科學(xué)依據(jù)。（郭建平）

2.20 中國(guó)北方蘋(píng)果干旱等級(jí)指標(biāo)構(gòu)建及危險(xiǎn)性評(píng)價(jià)

構(gòu)建蘋(píng)果干旱等級(jí)指標(biāo)體系，評(píng)估蘋(píng)果干旱危險(xiǎn)性，對(duì)開(kāi)展蘋(píng)果干旱防災(zāi)減災(zāi)、災(zāi)害保險(xiǎn)意義重大。本文以中國(guó)北方蘋(píng)果主產(chǎn)區(qū)為研究對(duì)象，利用氣象資料、蘋(píng)果干旱災(zāi)情史料和發(fā)育期資料，在干旱指數(shù)（DI）構(gòu)建的基礎(chǔ)上，以歷史災(zāi)情反演、災(zāi)害樣本重建和歷史災(zāi)害過(guò)程解析為主線(xiàn)，采用獨(dú)立樣本T檢驗(yàn)、K-S檢驗(yàn)、累積概率反函數(shù)值等方法，構(gòu)建適用于中國(guó)北方蘋(píng)果主產(chǎn)區(qū)的蘋(píng)果干旱等級(jí)指標(biāo)體系，并在此基礎(chǔ)上開(kāi)展蘋(píng)果干旱危險(xiǎn)性評(píng)價(jià)，結(jié)果表明：構(gòu)建的干旱指數(shù)（DI）能有效表征蘋(píng)果干旱災(zāi)害；同一等級(jí)蘋(píng)果干旱指標(biāo)閾值果樹(shù)萌動(dòng)—萌芽期＞萌芽—盛花期＞盛花—成熟期；蘋(píng)果危險(xiǎn)性萌芽—盛花期＞果樹(shù)萌動(dòng)—萌芽期＞盛花—成熟期，渤海灣產(chǎn)區(qū)及黃土高原產(chǎn)區(qū)北部是蘋(píng)果干旱的高危險(xiǎn)區(qū)域。基于歷史災(zāi)情資料加工與再分析的蘋(píng)果干旱等級(jí)指標(biāo)體系構(gòu)建方法可為經(jīng)濟(jì)林果氣象災(zāi)害研究提供新的思路，研究結(jié)果可為中國(guó)北方蘋(píng)果干旱防災(zāi)減損氣象服務(wù)、災(zāi)害保險(xiǎn)提供基礎(chǔ)支撐。（楊建瑩）

2.21 從土壤氣候視角解析農(nóng)業(yè)文化遺產(chǎn)地的自然稟賦——以寬城傳統(tǒng)板栗栽培系統(tǒng)為例

寬城傳統(tǒng)板栗栽培系統(tǒng)是中國(guó)重要農(nóng)業(yè)文化遺產(chǎn)，寬城板栗栽培歷史悠久，品質(zhì)優(yōu)良,為了從土壤氣候角度解析寬城板栗栽培系統(tǒng)的自然稟賦和不足，本文利用寬城縣基本氣象站和自動(dòng)氣象站的觀(guān)測(cè)資料以及專(zhuān)項(xiàng)進(jìn)行的土壤取樣分析數(shù)據(jù)全面分析了寬城板栗栽培的土壤和氣候條件，綜合評(píng)價(jià)了寬城板栗栽培的氣候適宜性及其空間分布。結(jié)果表明：寬城板栗林土壤酸堿度適宜，有機(jī)質(zhì)豐富，N、K含量和Fe、Mn、 Mg等微量元素含量較高，寬城光熱資源完全滿(mǎn)足板栗生長(zhǎng)成熟需要，果實(shí)生長(zhǎng)期水分供應(yīng)充足，果實(shí)成熟期氣溫日較差大，板栗主要栽培區(qū)域綜合氣候條件優(yōu)于板栗栽培適宜指標(biāo)?？傊瑢挸前謇踉耘嘞到y(tǒng)擁有較好的土壤氣候環(huán)境，具備栽培高產(chǎn)優(yōu)質(zhì)板栗的條件和潛力，春季降水偏少是寬城板栗高產(chǎn)的一個(gè)限制因素，適當(dāng)?shù)拇杭竟喔瓤奢^大幅度地促進(jìn)板栗高產(chǎn)優(yōu)質(zhì)潛力的發(fā)揮。（譚凱炎）

2.22 華北平原不同等級(jí)干旱對(duì)冬小麥產(chǎn)量的影響

華北平原是中國(guó)重要的糧食生產(chǎn)基地，其中冬小麥播種面積和產(chǎn)量均居中國(guó)首位，在國(guó)家糧食安全中具有重要作用，干旱是影響該區(qū)域冬小麥產(chǎn)量的最主要農(nóng)業(yè)氣象災(zāi)害。該研究基于華北平原44個(gè)氣象站點(diǎn)1981—2017年的逐日氣象數(shù)據(jù)以及作物、土壤和田間管理資料，以作物水分虧缺指數(shù)為農(nóng)業(yè)干旱指標(biāo)，基于調(diào)參驗(yàn)證后的農(nóng)業(yè)生產(chǎn)系統(tǒng)模型（APSIM），評(píng)估了冬小麥生長(zhǎng)發(fā)育中后期各生育階段不同等級(jí)干旱對(duì)冬小麥單產(chǎn)和總產(chǎn)的影響。結(jié)果表明，冬小麥拔節(jié)—開(kāi)花和開(kāi)花—成熟階段干旱造成冬小麥減產(chǎn)率空間上均呈北高南低的分布特征，且開(kāi)花—成熟階段干旱引起的減產(chǎn)率（26.8%）高于拔節(jié)—開(kāi)花階段干旱引起的減產(chǎn)率（19.1%），區(qū)域間比較均表現(xiàn)為干旱對(duì)京津冀地區(qū)冬小麥單產(chǎn)影響最大，對(duì)河南省冬小麥單產(chǎn)影響最小；隨著干旱等級(jí)的加重減產(chǎn)率增大，開(kāi)花—成熟階段輕旱、中旱和重旱的減產(chǎn)率分別為16.5%、32.8%和44.9%，拔節(jié)—開(kāi)花階段輕旱、中旱和重旱的減產(chǎn)率分別為10.3%、18.8%和28.6%。結(jié)合冬小麥實(shí)際播種面積得到各生育階段干旱對(duì)總產(chǎn)的影響，區(qū)域間比較均表現(xiàn)為干旱對(duì)山東省冬小麥總產(chǎn)影響最大，對(duì)河南省冬小麥總產(chǎn)影響最小。（孫爽）

2.23 我國(guó)北方一作區(qū)馬鈴薯高產(chǎn)穩(wěn)產(chǎn)區(qū)分布特征

北方一作區(qū)馬鈴薯種植面積和總產(chǎn)居我國(guó)首位，明確其高產(chǎn)穩(wěn)產(chǎn)區(qū)分布，對(duì)馬鈴薯合理布局具有重要意義?；谘芯繀^(qū)域內(nèi)234個(gè)氣象站點(diǎn)1981—2019年逐日氣象數(shù)據(jù)以及作物、土壤資料，利用APSIM-Potato模型，以產(chǎn)量平均值和變異系數(shù)為高產(chǎn)性和穩(wěn)產(chǎn)性評(píng)價(jià)指標(biāo)，將研究區(qū)域劃分為高產(chǎn)高穩(wěn)、高產(chǎn)低穩(wěn)、低產(chǎn)高穩(wěn)和低產(chǎn)低穩(wěn)4個(gè)亞區(qū)，明確了過(guò)去39年不同生產(chǎn)水平下我國(guó)北方一作區(qū)馬鈴薯高產(chǎn)穩(wěn)產(chǎn)區(qū)分布特征，解析了降水和土壤對(duì)馬鈴薯高產(chǎn)性和穩(wěn)產(chǎn)性的影響。結(jié)果表明：過(guò)去39年不同生產(chǎn)水平下馬鈴薯高產(chǎn)區(qū)比例呈下降趨勢(shì)；隨著限制因素增加，高產(chǎn)高穩(wěn)區(qū)面積比例逐漸降低，氣候—土壤潛在生產(chǎn)水平下高產(chǎn)高穩(wěn)區(qū)面積比例僅占研究區(qū)域總面積的13%；高產(chǎn)低穩(wěn)區(qū)是潛在的高產(chǎn)高穩(wěn)區(qū)，需重點(diǎn)關(guān)注，及時(shí)采取有效措施提升穩(wěn)產(chǎn)性。降水對(duì)馬鈴薯高產(chǎn)性和穩(wěn)產(chǎn)性的影響大于土壤因素。實(shí)際生產(chǎn)中，降水和土壤限制下高產(chǎn)性和穩(wěn)產(chǎn)性降低的區(qū)域，應(yīng)注意結(jié)合當(dāng)?shù)毓喔葪l件配合耕作措施，以確保馬鈴薯高產(chǎn)穩(wěn)產(chǎn)。（孫爽）

2.24 中國(guó)大陸茶樹(shù)種植氣候適宜性區(qū)劃

基于1961—2019年全國(guó)1903個(gè)氣象站點(diǎn)的氣候數(shù)據(jù)以及1115條茶樹(shù)分布站點(diǎn)記錄，利用最大熵模型和GIS技術(shù)篩選影響茶樹(shù)種植的主導(dǎo)氣候因子，根據(jù)自然間斷點(diǎn)分級(jí)法將中國(guó)大陸茶樹(shù)氣候適宜性劃分為不適宜區(qū)、次適宜區(qū)、適宜區(qū)和高適宜區(qū)4個(gè)等級(jí)，厘定不同區(qū)劃等級(jí)的主導(dǎo)氣候因子閾值。結(jié)果表明，影響中國(guó)大陸地區(qū)茶樹(shù)種植分布的主導(dǎo)氣候因子為多年平均極端最低氣溫、春霜凍頻率、年平均氣溫、年降水量和3—9月平均相對(duì)濕度。模型區(qū)劃結(jié)果與名茶之鄉(xiāng)、地理標(biāo)志茶葉所在地吻合較好。茶樹(shù)適生區(qū)的北界總體呈現(xiàn)出由東部高緯度向西部低緯度降低的分布態(tài)勢(shì)，北界界限移動(dòng)較明顯地區(qū)主要分布在東部高緯度省份。整體茶樹(shù)適生區(qū)質(zhì)心的年代際變化較為平緩，除20世紀(jì)60—70年代和80—90年代的適生區(qū)范圍有所縮小外，其他相鄰年代際間茶樹(shù)適生區(qū)的面積均呈現(xiàn)出不同程度的增長(zhǎng)趨勢(shì)，與質(zhì)心遷移情況相吻合。（王培娟）

2.25 中國(guó)茶樹(shù)春霜凍害研究進(jìn)展

茶樹(shù)作為我國(guó)主要的經(jīng)濟(jì)作物，在早春萌發(fā)時(shí)易遭受霜凍害。本文系統(tǒng)歸納了茶樹(shù)春霜凍害的研究進(jìn)展和取得的主要成果，并對(duì)未來(lái)茶樹(shù)春霜凍害研究進(jìn)行展望。我國(guó)茶樹(shù)春霜凍多發(fā)于長(zhǎng)江中下游，霜凍災(zāi)害指標(biāo)可按照獲取方法、數(shù)據(jù)類(lèi)別、氣象數(shù)據(jù)的時(shí)間尺度進(jìn)一步細(xì)分。在全球變暖的背景下，茶樹(shù)春霜凍發(fā)生次數(shù)雖呈下降趨勢(shì)，但其危害不可忽視；其中，江南茶區(qū)茶樹(shù)春霜凍的發(fā)生頻率呈現(xiàn)出由南向北逐漸增加的緯向分布以及隨海拔的升高而增大的地形分布特征。茶樹(shù)春霜凍影響評(píng)估目前多集中于江蘇、浙江、安徽、江西等茶區(qū)，且逐步由定性向定量發(fā)展；風(fēng)險(xiǎn)評(píng)估主要基于自然災(zāi)害風(fēng)險(xiǎn)形成機(jī)制劃分不同的風(fēng)險(xiǎn)等級(jí)。今后，完善茶樹(shù)春霜凍的氣象指標(biāo)、構(gòu)建基于茶園小氣候的茶樹(shù)春霜凍災(zāi)害指標(biāo)、闡明國(guó)家尺度上茶樹(shù)春霜凍的時(shí)空分布特征、開(kāi)展精細(xì)化茶樹(shù)春霜凍風(fēng)險(xiǎn)評(píng)估將備受關(guān)注。（王培娟）

2.26 基于多種算法的果樹(shù)果實(shí)生長(zhǎng)模型研究——以云南昭通蘋(píng)果為例

針對(duì)果樹(shù)果實(shí)與生長(zhǎng)過(guò)程中的氣象因子關(guān)聯(lián)密切，且生長(zhǎng)過(guò)程多為非線(xiàn)性、非平穩(wěn)序列，直接對(duì)其連續(xù)測(cè)定難度較大的問(wèn)題，對(duì)比多種模型對(duì)果實(shí)直徑的模擬能力，為果樹(shù)及其果實(shí)的生長(zhǎng)發(fā)育監(jiān)測(cè)和預(yù)測(cè)、適時(shí)灌溉施肥、生長(zhǎng)環(huán)境調(diào)控等提供科學(xué)參考。以云南昭通蘋(píng)果為例，分析2019和2020年果實(shí)生長(zhǎng)期間直徑變化特征及其與環(huán)境氣候因子的關(guān)系。引入深度學(xué)習(xí)中的長(zhǎng)短期記憶模型（LSTM），使用LSTM模型對(duì)蘋(píng)果果實(shí)直徑進(jìn)行模擬及預(yù)測(cè)，與多元線(xiàn)性回歸模型（MLR）和機(jī)器學(xué)習(xí)模型中的決策樹(shù)（DT）及隨機(jī)森林（RF）模型的模擬結(jié)果進(jìn)行對(duì)比分析，并使用3種采樣方法對(duì)不同模型模擬的結(jié)果進(jìn)行評(píng)估。蘋(píng)果果實(shí)直徑有明顯日變化特征，呈夜間直徑增長(zhǎng)而白天縮小為主的規(guī)律，一般早晨直徑達(dá)到最大，然后逐漸微縮，在日落前后直徑到達(dá)當(dāng)日最小。蘋(píng)果果實(shí)直徑的增長(zhǎng)速率在果實(shí)膨大初期較高，在果實(shí)生長(zhǎng)后期降低。蘋(píng)果果實(shí)小時(shí)和日平均直徑與土壤溫度和土壤濕度呈中度或高度正相關(guān)，與紫外線(xiàn)指數(shù)（UVI）呈高度負(fù)相關(guān)。蘋(píng)果果實(shí)直徑的日平均增長(zhǎng)量（FMDG）、日增長(zhǎng)量（FDG）、日最大變化量（MDFS）與60 cm土壤溫度和20、40 cm土壤濕度呈低負(fù)相關(guān)（-0.5≤R＜-0.3）。4個(gè)模型的模擬結(jié)果相比，LSTM模型的模擬精度高于MLR、DT和RF模型。LSTM模型比MLR模型在相關(guān)系數(shù)R增加3%～20%的情況下，RMSE和MAE下降50%～75%，而機(jī)器學(xué)習(xí)模型DT和RF對(duì)蘋(píng)果果實(shí)直徑的預(yù)測(cè)相對(duì)較差，可能存在過(guò)度擬合。對(duì)比統(tǒng)計(jì)學(xué)、機(jī)器學(xué)習(xí)和深度學(xué)習(xí)等方法，LSTM模型在蘋(píng)果果實(shí)直徑的模擬中表現(xiàn)出更高的精度和可靠性，能更好地解決果實(shí)生長(zhǎng)過(guò)程中的復(fù)雜非線(xiàn)性問(wèn)題。（孫擎）