分类： 地球科学 >> 大气科学 提交时间： 2024-06-21 合作期刊: 《干旱区科学》
摘要： Vapor pressure deficit (VPD) plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation, second only to carbon dioxide (CO2). As a robust indicator of atmospheric water demand, VPD has implications for global water resources, and its significance extends to the structure and functioning of ecosystems. However, the influence of VPD on vegetation growth under climate change remains unclear in China. This study employed empirical equations to estimate the VPD in China from 2000 to 2020 based on meteorological reanalysis data of the Climatic Research Unit (CRU) Time-Series version 4.06 (TS4.06) and European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis 5 (ERA-5). Vegetation growth status was characterized using three vegetation indices, namely gross primary productivity (GPP), leaf area index (LAI), and near-infrared reflectance of vegetation (NIRv). The spatiotemporal dynamics of VPD and vegetation indices were analyzed using the Theil-Sen median trend analysis and Mann-Kendall test. Furthermore, the influence of VPD on vegetation growth and its relative contribution were assessed using a multiple linear regression model. The results indicated an overall negative correlation between VPD and vegetation indices. Three VPD intervals for the correlations between VPD and vegetation indices were identified: a significant positive correlation at VPD below 4.820 hPa, a significant negative correlation at VPD within 4.820–9.000 hPa, and a notable weakening of negative correlation at VPD above 9.000 hPa. VPD exhibited a pronounced negative impact on vegetation growth, surpassing those of temperature, precipitation, and solar radiation in absolute magnitude. CO2 contributed most positively to vegetation growth, with VPD offsetting approximately 30.00% of the positive effect of CO2. As the rise of VPD decelerated, its relative contribution to vegetation growth diminished. Additionally, the intensification of spatial variations in temperature and precipitation accentuated the spatial heterogeneity in the impact of VPD on vegetation growth in China. This research provides a theoretical foundation for addressing climate change in China, especially regarding the challenges posed by increasing VPD
分类： 地球科学 >> 大气科学 提交时间： 2024-06-21 合作期刊: 《干旱区科学》
摘要： Methane (CH4) is a potent greenhouse gas that has a substantial impact on global warming due to its substantial influence on the greenhouse effect. Increasing extreme precipitation events, such as drought, attributable to global warming that caused by greenhouse gases, exert a profound impact on the intricate biological processes associated with CH4 uptake. Notably, the timing of extreme drought occurrence emerges as a pivotal factor influencing CH4 uptake, even when the degree of drought remains constant. However, it is still unclear how the growing season regulates the response of CH4 uptake to extreme drought. In an effort to bridge this knowledge gap, we conducted a field manipulative experiment to evaluate the impact of extreme drought on CH4 uptake during early, middle, and late growing stages in a temperate steppe of Inner Mongolia Autonomous Region, China. The result showed that all extreme drought consistently exerted positive effects on CH4 uptake regardless of seasonal timing. However, the magnitude of this effect varied depending on the timing of season, as evidenced by a stronger effect in early growing stage than in middle and late growing stages. Besides, the pathways of CH4 uptake were different from seasonal timing. Extreme drought affected soil physical-chemical properties and aboveground biomass (AGB), consequently leading to changes in CH4 uptake. The structural equation model showed that drought both in the early and middle growing stages enhanced CH4 uptake due to reduced soil water content (SWC), leading to a decrease in NO3–-N and an increase in pmoA abundance. However, drought in late growing stage primarily enhanced CH4 uptake only by decreasing SWC. Our results suggested that seasonal timing significantly contributed to regulate the impacts of extreme drought pathways and magnitudes on CH4 uptake. The findings can provide substantial implications for understanding how extreme droughts affect CH4 uptake and improve the prediction of potential ecological consequence under future climate change.
分类： 地球科学 >> 大气科学 提交时间： 2024-06-21 合作期刊: 《干旱区科学》
摘要： Stable water isotopes are natural tracers quantifying the contribution of moisture recycling to local precipitation, i.e., the moisture recycling ratio, but various isotope-based models usually lead to different results, which affects the accuracy of local moisture recycling. In this study, a total of 18 stations from four typical areas in China were selected to compare the performance of isotope-based linear and Bayesian mixing models and to determine local moisture recycling ratio. Among the three vapor sources including advection, transpiration, and surface evaporation, the advection vapor usually played a dominant role, and the contribution of surface evaporation was less than that of transpiration. When the abnormal values were ignored, the arithmetic averages of differences between isotope-based linear and the Bayesian mixing models were 0.9% for transpiration, 0.2% for surface evaporation, and –1.1% for advection, respectively, and the medians were 0.5%, 0.2%, and –0.8%, respectively. The importance of transpiration was slightly less for most cases when the Bayesian mixing model was applied, and the contribution of advection was relatively larger. The Bayesian mixing model was found to perform better in determining an efficient solution since linear model sometimes resulted in negative contribution ratios. Sensitivity test with two isotope scenarios indicated that the Bayesian model had a relatively low sensitivity to the changes in isotope input, and it was important to accurately estimate the isotopes in precipitation vapor. Generally, the Bayesian mixing model should be recommended instead of a linear model. The findings are useful for understanding the performance of isotope-based linear and Bayesian mixing models under various climate backgrounds.
分类： 地球科学 >> 大气科学 提交时间： 2024-05-15 合作期刊: 《干旱区科学》
摘要： The desert-oasis transition zone (DOTZ) serves as a buffer area between the desert and oasis. Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis. In this study, we used meteorological data during 2013–2019 from the portable meteorological stations at five sites (site A on the edge of the oasis, sites B, C, and D in the DOTZ, and site O in the desert) in Dunhuang, China to analyze the near-surface wind field characteristics and their causes, as well as to reveal the key role of the DOTZ in oasis protection. The results showed that the mean wind speed, frequency of sand-driving wind, and directional variability of wind decreased from west to east within the DOTZ, and wind speed was significantly affected by air temperature. The terrain influenced the prevailing winds in the region, mainly from northeast and southwest. Only some areas adjacent to the oasis were controlled by southeasterly wind. This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference. At site D, the annual drift potential (DP) was 24.95 vector units (VU), indicating a low wind energy environment, and the resultant drift direction (RDD) showed obvious seasonal differences. Additionally, the DOTZ played an important buffering role between the desert and oasis. Compared with the desert, the mean wind speed in the oasis decreased by 64.98%, and the prevailing wind direction was more concentrated. The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.
分类： 地球科学 >> 大气科学 提交时间： 2024-04-15 合作期刊: 《干旱区科学》
摘要： Rain-on-snow (ROS) events involve rainfall on snow surfaces, and the occurrence of ROS events can exacerbate water scarcity and ecosystem vulnerability in the arid region of Northwest China (ARNC). In this study, using daily snow depth data and daily meteorological data from 68 meteorological stations provided by the China Meteorological Administration National Meteorological Information Centre, we investigated the spatiotemporal variability of ROS events in the ARNC from 1978 to 2015 and examined the factors affecting these events and possible changes of future ROS events in the ARNC. The results showed that ROS events in the ARNC mainly occurred from October to May of the following year and were largely distributed in the Qilian Mountains, Tianshan Mountains, Ili River Valley, Tacheng Prefecture, and Altay Prefecture, with the Ili River Valley, Tacheng City, and Altay Mountains exhibiting the most occurrences. Based on the intensity of ROS events, the areas with the highest risk of flooding resulting from ROS events in the ARNC were the Tianshan Mountains, Ili River Valley, Tacheng City, and Altay Mountains. The number and intensity of ROS events in the ARNC largely increased from 1978 to 2015, mainly influenced by air temperature and the number of rainfall days. However, due to the snowpack abundance in areas experiencing frequent ROS events in the ARNC, snowpack changes exerted slight impact on ROS events, which is a temporary phenomenon. Furthermore, elevation imposed lesser impact on ROS events in the ARNC than other factors. In the ARNC, the start time of rainfall and the end time of snowpack gradually advanced from the spring of the current year to the winter of the previous year, while the end time of rainfall and the start time of snowpack gradually delayed from autumn to winter. This may lead to more ROS events in winter in the future. These results could provide a sound basis for managing water resources and mitigating related disasters caused by ROS events in the ARNC.
分类： 地球科学 >> 大气科学 提交时间： 2024-03-13 合作期刊: 《干旱区科学》
摘要： Land surface temperature (LST) directly affects the energy balance of terrestrial surface systems and impacts regional resources, ecosystem evolution, and ecosystem structures. Xinjiang Uygur Autonomous Region is located at the arid Northwest China and is extremely sensitive to climate change. There is an urgent need to understand the distribution patterns of LST in this area and quantitatively measure the nature and intensity of the impacts of the major driving factors from a spatial perspective, as well as elucidate the formation mechanisms. In this study, we used the MOD11C3 LST product developed on the basis of Moderate Resolution Imaging Spectroradiometer (MODIS) to conduct regression analysis and determine the spatiotemporal variation and differentiation pattern of LST in Xinjiang from 2000 to 2020. We analyzed the driving mechanisms of spatial heterogeneity of LST in Xinjiang and the six geomorphic zones (the Altay Mountains, Junggar Basin, Tianshan Mountains, Tarim Basin, Turpan-Hami (Tuha) Basin, and Pakakuna Mountain Group) using geographical detector (Geodetector) and geographically weighted regression (GWR) models. The warming rate of LST in Xinjiang during the study period was 0.24°C/10a, and the spatial distribution pattern of LST had obvious topographic imprints, with 87.20% of the warming zone located in the Gobi desert and areas with frequent human activities, and the cooling zone mainly located in the mountainous areas. The seasonal LST in Xinjiang was at a cooling rate of 0.09°C/10a in autumn, and showed a warming trend in other seasons. Digital elevation model (DEM), latitude, wind speed, precipitation, normalized difference vegetation index (NDVI), and sunshine duration in the single-factor and interactive detections were the key factors driving the LST changes. The direction and intensity of each major driving factor on the spatial variations of LST in the study area were heterogeneous. The negative feedback effect of DEM on the spatial differentiation of LST was the strongest. Lower latitudes, lower vegetation coverage, lower levels of precipitation, and longer sunshine duration increased LST. Unused land was the main heat source landscape, water body was the most important heat sink landscape, grassland and forest land were the land use and land cover (LULC) types with the most prominent heat sink effect, and there were significant differences in different geomorphic zones due to the influences of their vegetation types, climatic conditions, soil types, and human activities. The findings will help to facilitate sustainable climate change management, analyze local climate and environmental patterns, and improve land management strategies in Xinjiang and other arid areas.
分类： 地球科学 >> 大气科学 提交时间： 2024-03-13 合作期刊: 《干旱区科学》
摘要： The isotope composition in precipitation has been widely considered as a tracer of monsoon activity. Compared with the coastal region, the monsoon margin usually has limited precipitation with large fluctuation and is usually sensitive to climate change. The water resource management in the monsoon margin should be better planned by understanding the composition of precipitation isotope and its influencing factors. In this study, the precipitation samples were collected at five sampling sites (Baiyin City, Kongtong District, Maqu County, Wudu District, and Yinchuan City) of the monsoon margin in the northwest of China in 2022 to analyze the characteristics of stable hydrogen (δD) and oxygen (δ18O) isotopes. We analyzed the impact of meteorological factors (temperature, precipitation, and relative humidity) on the composition of precipitation isotope at daily level by regression analysis, utilized the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT)-based backward trajectory model to simulate the air mass trajectory of precipitation events, and adopted the potential source contribution function (PSCF) and concentration weighted trajectory (CWT) to analyze the water vapor sources. The results showed that compared with the global meteoric water line (GMWL), the slope of the local meteoric water line (LMWL; δD=7.34δ18O–1.16) was lower, indicating the existence of strong regional evaporation in the study area. Temperature significantly contributed to δ18O value, while relative humidity had a significant negative effect on δ18O value. Through the backward trajectory analysis, we found eight primary locations that were responsible for the water vapor sources of precipitation in the study area, of which moisture from the Indian Ocean to South China Sea (ITSC) and the western continental (CW) had the greatest influence on precipitation in the study area. The hydrogen and oxygen isotopes in precipitation are significantly influenced by the sources and transportation paths of air mass. In addition, the results of PSCF and CWT analysis showed that the water vapor source areas were primarily distributed in the south and northwest direction of the study area.
分类： 地球科学 >> 大气科学 提交时间： 2024-03-13 合作期刊: 《干旱区科学》
摘要： Xinjiang Uygur Autonomous Region is a typical inland arid area in China with a sparse and uneven distribution of meteorological stations, limited access to precipitation data, and significant water scarcity. Evaluating and integrating precipitation datasets from different sources to accurately characterize precipitation patterns has become a challenge to provide more accurate and alternative precipitation information for the region, which can even improve the performance of hydrological modelling. This study evaluated the applicability of widely used five satellite-based precipitation products (Climate Hazards Group InfraRed Precipitation with Station (CHIRPS), China Meteorological Forcing Dataset (CMFD), Climate Prediction Center morphing method (CMORPH), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR), and Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA)) and a reanalysis precipitation dataset (ECMWF Reanalysis v5-Land Dataset (ERA5-Land)) in Xinjiang using ground-based observational precipitation data from a limited number of meteorological stations. Based on this assessment, we proposed a framework that integrated different precipitation datasets with varying spatial resolutions using a dynamic Bayesian model averaging (DBMA) approach, the expectation-maximization method, and the ordinary Kriging interpolation method. The daily precipitation data merged using the DBMA approach exhibited distinct spatiotemporal variability, with an outstanding performance, as indicated by low root mean square error (RMSE=1.40 mm/d) and high Person's correlation coefficient (CC=0.67). Compared with the traditional simple model averaging (SMA) and individual product data, although the DBMA-fused precipitation data were slightly lower than the best precipitation product (CMFD), the overall performance of DBMA was more robust. The error analysis between DBMA-fused precipitation dataset and the more advanced Integrated Multi-satellite Retrievals for Global Precipitation Measurement Final (IMERG-F) precipitation product, as well as hydrological simulations in the Ebinur Lake Basin, further demonstrated the superior performance of DBMA-fused precipitation dataset in the entire Xinjiang region. The proposed framework for solving the fusion problem of multi-source precipitation data with different spatial resolutions is feasible for application in inland arid areas, and aids in obtaining more accurate regional hydrological information and improving regional water resources management capabilities and meteorological research in these regions.
分类： 地球科学 >> 大气科学 提交时间： 2024-02-21 合作期刊: 《干旱区科学》
摘要： Climate warming profoundly affects hydrological changes, agricultural production, and human society. Arid and semi-arid areas of China are currently displaying a marked trend of warming and wetting. The Chinese Tianshan Mountains (CTM) have a high climate sensitivity, rendering the region particularly vulnerable to the effects of climate warming. In this study, we used monthly average temperature and monthly precipitation data from the CN05.1 gridded dataset (1961–2014) and 24 global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 6 (CMIP6) to assess the applicability of the CMIP6 GCMs in the CTM at the regional scale. Based on this, we conducted a systematic review of the interannual trends, dry–wet transitions (based on the standardized precipitation index (SPI)), and spatial distribution patterns of climate change in the CTM during 1961–2014. We further projected future temperature and precipitation changes over three terms (near-term (2021–2040), mid-term (2041–2060), and long-term (2081–2100)) relative to the historical period (1961–2014) under four shared socio-economic pathway (SSP) scenarios (i.e., SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). It was found that the CTM had experienced significant warming and wetting from 1961 to 2014, and will also experience warming in the future (2021–2100). Substantial warming in 1997 was captured by both the CN05.1 derived from interpolating meteorological station data and the multi-model ensemble (MME) from the CMIP6 GCMs. The MME simulation results indicated an apparent wetting in 2008, which occurred later than the wetting observed from the CN05.1 in 1989. The GCMs generally underestimated spring temperature and overestimated both winter temperature and spring precipitation in the CTM. Warming and wetting are more rapid in the northern part of the CTM. By the end of the 21st century, all the four SSP scenarios project warmer and wetter conditions in the CTM with multiple dry–wet transitions. However, the rise in precipitation fails to counterbalance the drought induced by escalating temperature in the future, so the nature of the drought in the CTM will not change at all. Additionally, the projected summer precipitation shows negative correlation with the radiative forcing. This study holds practical implications for the awareness of climate change and subsequent research in the CTM.
分类： 地球科学 >> 大气科学 提交时间： 2024-02-07 合作期刊: 《干旱区科学》
摘要： Climate warming profoundly affects hydrological changes, agricultural production, and human society. Arid and semi-arid areas of China are currently displaying a marked trend of warming and wetting. The Chinese Tianshan Mountains (CTM) have a high climate sensitivity, rendering the region particularly vulnerable to the effects of climate warming. In this study, we used monthly average temperature and monthly precipitation data from the CN05.1 gridded dataset (19612014) and 24 global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 6 (CMIP6) to assess the applicability of the CMIP6 GCMs in the CTM at the regional scale. Based on this, we conducted a systematic review of the interannual trends, drywet transitions (based on the standardized precipitation index (SPI)), and spatial distribution patterns of climate change in the CTM during 19612014. We further projected future temperature and precipitation changes over three terms (near-term (20212040), mid-term (20412060), and long-term (20812100)) relative to the historical period (19612014) under four shared socio-economic pathway (SSP) scenarios (i.e., SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). It was found that the CTM had experienced significant warming and wetting from 1961 to 2014, and will also experience warming in the future (20212100). Substantial warming in 1997 was captured by both the CN05.1 derived from interpolating meteorological station data and the multi-model ensemble (MME) from the CMIP6 GCMs. The MME simulation results indicated an apparent wetting in 2008, which occurred later than the wetting observed from the CN05.1 in 1989. The GCMs generally underestimated spring temperature and overestimated both winter temperature and spring precipitation in the CTM. Warming and wetting are more rapid in the northern part of the CTM. By the end of the 21st century, all the four SSP scenarios project warmer and wetter conditions in the CTM with multiple drywet transitions. However, the rise in precipitation fails to counterbalance the drought induced by escalating temperature in the future, so the nature of the drought in the CTM will not change at all. Additionally, the projected summer precipitation shows negative correlation with the radiative forcing. This study holds practical implications for the awareness of climate change and subsequent research in the CTM.
分类： 地球科学 >> 大气科学 提交时间： 2023-12-16 合作期刊: 《干旱区研究》
摘要： 利用19612020年宁夏逐日最低气温观测资料及同期位势高度、海平面气压场和风场逐月再分析资料，分析近60 a宁夏24 h、48 h、72 h不同历时寒潮、强寒潮、超强寒潮的时空演变特征，并进一步揭示寒潮变化的大气环流异常特征。结果表明：（1）宁夏近60 a不同强度、不同历时寒潮一致表现为东多西少、北多南少的分布特征，这与冷空气路径及宁夏地形有关。（2）全区寒潮、强寒潮、超强寒潮频次分别占全年总寒潮频次的71.7%、22.6%和5.7%，寒潮以24 h和48 h为主，而强寒潮及超强寒潮不同历时的频次比例相当；各类寒潮存在14月递减、1012月递增的逐月变化特征。（3）宁夏近60 a寒潮、强寒潮、超强寒潮分别以4.5站次（10a）-1、2.8站次（10a）-1及0.18站次（10a）-1的速率减少，其中24 h及48 h短历时频次减少，但72 h长历时增多；且1960s最多，之后波动减少，1990s达到最少，2000s以来波动增多，20世纪80年代后期寒潮及强寒潮发生突变。（4）宁夏寒潮突变前后的大气环流呈现出完全相反的分布特征，之前环流形势利于极地冷空气活跃南下，之后则相反；但19612020年及突变前后宁夏寒潮的关键影响系统较为一致，当乌山阻高异常偏强、东亚大槽偏强、欧洲西岸高度场异常偏低、贝加尔湖西侧以气旋性环流为主、极地冷高压活跃时，有利于中高纬冷空气活跃南下，宁夏寒潮则偏多，反之则偏少。
分类： 地球科学 >> 大气科学 提交时间： 2023-12-16 合作期刊: 《干旱区研究》
摘要： 基于塔里木盆地32个气象站点19642022年观测数据，采用Sen+M-K趋势分析、重心移动模型、标准化回归系数和空间聚类方法，从空间特征角度着重分析塔里木盆地不同类型沙尘年日数的变化、趋势和移动规律，以及影响因素的贡献率。结果表明：（1）盆地以浮尘为主，其次是扬沙、沙尘暴，总体呈现南多北少的空间分布格局，且具有显著下降趋势。（2）盆地不同类型沙尘日数的重心呈向东南部移动的趋势，其中沙尘暴重心移动幅度最大。（3）气温升高、风速降低和大风日数减少是塔里木盆地沙尘日数减少的主要影响因素，降水量影响最小。（4）降水量对沙尘变化的贡献率高值聚集在盆地西部，平均气温和平均最高气温分别在盆地南部和西部，而大风日数和平均风速分别在盆地西北部和东南部。研究结果可为塔里木盆地有针对性的制定区域适用性防风固沙措施提供科学依据。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-26 合作期刊: 《干旱区研究》
摘要： 分析树木径向生长对气候变化的响应，有利于准确预测未来森林的动态变化。天山北坡中山带广泛分布着以雪岭云杉（Picea schrenkiana）为单优树种的温带针叶林，本研究采集该处高海拔雪岭云杉树芯样本，用树木年轮学方法探究雪岭云杉径向生长对气候因子及干旱事件的响应特征。结果表明：（1）19602020年，雪岭云杉树轮宽度指数呈极显著上升趋势，未出现生长衰退现象，表明近期雪岭云杉生长状况良好。（2）雪岭云杉树轮宽度主要与当年68月气温，4月降水及除当年7月外的各月scPDSI显著正相关；滑动相关显示，雪岭云杉树轮宽度与气候因子的关系不稳定，1991年后，云杉对气候因子的正响应进一步加强。（3）雪岭云杉径向生长变化百分率在18791880年低于－25%，表明其在18791885年发生了生长衰退；随干旱频率和强度的增加，雪岭云杉应对干旱事件的抵抗力和恢复力下降，当云杉长时间处于水分较充足的环境而遭受突发干旱事件时，会导致其抵抗力严重下降，易发生生长衰退。综上所述，在气候变化背景下，升温在近期仍有利于该区域高海拔雪岭云杉径向生长，但升温过程中伴随着干旱频率和强度的增加，将使雪岭云杉的抵抗力和恢复力进一步下降，生长衰退风险升高。即在近期，雪岭云杉会在升温促进生长和干旱抑制生长间不断博弈，最终产生何种影响需进一步观察研究，未来应采取多种手段密切监测其生长动态。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-26 合作期刊: 《干旱区研究》
摘要： 利用20202021年六盘山区58次降雨过程不同站点的雨滴谱数据，对层状云、对流云、积层混合云三类降雨的微物理参量、雨滴谱平均特征，以及Gamma分布参数等进行了分析。结果表明：（1）同一站点的各微物理参量以及特征直径均值表现为：对流云>积层混合云>层状云；在层状云和积层混合云中，平均直径Dave、众数直径Dmode表现为山腰大于山顶和山底，随着东、西坡两侧海拔高度的升高，其最大直径Dmax、质量加权平均直径Dm、雨强R、雷达反射率Z、液态含水量Q 逐渐增大；（2）层状云和积层混合云小雨滴对雨强和数浓度的贡献均为最大，对流云小雨滴对数浓度贡献最大，而中等雨滴对雨强的贡献最大；（3）Gamma分布的参数N0（阶距参数）、（形状参数）、（斜率参数）随着海拔高度的升高而减小，-拟合曲线的斜率与降水类型密切相关；（4）山顶站点雨滴粒子数浓度Nw较山脚站点有所减小，而平均尺度Dm增大；（5）西北气流型的雨滴谱各特征直径参量及各微物理参量大于东高西低型和平直气流型。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 基于疏勒河流域敦煌站、瓜州站和玉门站19512020年气温实测数据，采用线性倾向、累计距平、Mann-Kendall检验等方法，分析各站气温时空变化特征。结果表明：（1）疏勒河流域各站平均气温均呈显著上升趋势，倾向率排序表现为：敦煌站（0.244 ℃(10a)-1，P瓜州站（0.209 ℃(10a)-1，P玉门站（0.195 ℃(10a)-1，P<0.05）。（2）敦煌站、玉门站四季平均气温呈显著上升趋势；瓜州站春季、秋季、冬季平均气温呈显著上升趋势，夏季平均气温呈不显著上升趋势。（3）疏勒河流域各站平均气温突变年份分别为1998年、1997年和1995年；第一主周期分别为58 a、30 a、13 a。（4）疏勒河流域全年及四季平均气温从东向西逐渐升高，不均匀系数和集中度均呈下降趋势。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 基于ECMWF细网格数值预报产品和国家级考核站气温观测数据，采用加权准对称滑动训练期方法（WQSRTP）生成甘肃省智能网格最高（低）客观产品，检验该产品的预报效果，将其与中国气象局智能网格指导预报产品（SCMOC）、甘肃省城镇网格预报产品（SPCC）进行对比。结果表明：WQSRTP订正方法能够显著改善ECMWF细网格数值模式24 h最高（低）气温的预报能力，24 h最高、最低气温预报准确率分别提升了32.16%、15.48%；WQSRTP订正产品相对于SCMOC、SPCC和ECMWF最高（低）气温产品均为正订正技巧，且最高气温订正能力优于最低气温订正能力。空间误差检验来看，WQSRTP订正方法可有效提升祁连山区和甘岷山区等地形复杂地区的最高（低）气温预报准确率，显著降低了平均绝对误差。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 基于20012020年新疆阿尔泰山的MOD10A2积雪产品数据，结合DEM及气象数据，分析近20 a阿尔泰山积雪时空变化特征及地形、气象因素对积雪覆盖的影响。结果表明：（1）年均积雪覆盖率（SCP）年际变化总体呈不显著减少趋势，变化率为-0.88%(10a)-1。积雪变化具有明显季节性，其中秋季呈增加趋势，冬季呈显著减小趋势。年内积雪从10月开始积累，1月SCP值达到最大。（2）SCP与海拔呈正相关关系。不同坡向区域的SCP区别较大，最高值是西北坡，为28.45%，南坡最低，为18.36%。（3）积雪覆盖频率（SCF）整体呈现出东北高、西南低的分布格局，与海拔呈显著正相关，其中有67.65%的区域SCF呈减少趋势。高山区SCF呈上升趋势而平原及河流区呈下降趋势。（4）气温是影响新疆阿尔泰山积雪变化的主要因素，与SCF呈显著负相关。随着海拔逐渐升高，气温对积雪的影响逐渐减小。新疆阿尔泰山年均降水量呈现从西北部向东南部逐渐降低的空间分布特征，SCF与降水量总体呈正相关。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 基于目前主流气候业务模式系统（BCC_CSM 1.1、ECMWF_System 5、NCEP_CFSv 2、TCC_MRI-CGCM 3），从确定性预报角度评估多种模式对青藏高原前冬降水的预测性能。结果表明：多模式均能体现出青藏高原前冬（1112月）降水空间分布型，但对降水量级存在普遍高估的现象，其中，来自BCC的模式能反映出降水全区一致型和南北反向型主模态的时空演变特征，EC模式高估第一模态的主导作用。多模式对降水历史回报以正技巧为主，BCC模式的预报技巧最优，TCC仅对青藏高原北部预测较好。从可预报性来源的角度分析发现，赤道中东太平洋海温指数（Nio 3.4）和印度洋偶极子（IOD）正位相对提升模式预测技巧具有很好的指示性；BCC模式能预测出2018年高原前冬降水异常趋势，在于其对影响青藏高原降水异常的关键环流型具有一定预测能力。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 通过分析19902020年北非埃及气象观测数据和卫星遥感资料，研究风蚀沙尘的时空变化特点，并阐明主要影响因素。结果显示：埃及近30 a沙尘天气发生频次在20~65 da-1之间变化，整体呈现出逐渐降低的变化趋势，总悬浮颗粒物（Total Suspended Particulates，TSP）年均浓度在400~1200 gmg-3之间波动，在全球干旱区处于较高强度水平；扬沙天气发生频率最高，其次是浮尘、沙尘暴和强沙尘暴天气，其中春、夏两季扬沙天气日数占全年沙尘天气总日数的60%以上，环境TSP浓度与沙尘天气发生频次高度相关；近30 a埃及地面风速呈现减小趋势，风力侵蚀作用是影响地区空气质量的关键因素；沙尘天气频率与大西洋多年代际振荡（Atlantic Multidecadal Oscillation，AMO）指数显著负相关，相关系数约为-0.67。本研究为全面了解北非埃及地区风蚀沙尘的时空变化特征和预防沙尘暴灾害提供理论依据和数据支持。
分类： 地球科学 >> 大气科学 提交时间： 2023-08-25 合作期刊: 《干旱区研究》
摘要： 为研究宁夏大气环境容量变化及其影响因子，利用19612018年气象站逐日历史观测资料，根据箱模型原理对宁夏大气环境容量A（污染物排放总量控制系数）值时空分布及其主要气象影响因子进行分析，并对2018年大气环境容量进行区划评估。结果表明：宁夏各季节大气环境容量A 值总体呈减小趋势，速率为-0.47104～-0.24104 km2(10a)-1。各季节A 值夏季最大，春季次之，秋季和冬季较小。月A 值呈单峰型变化，8月最大、12月最小，空间上呈南高北低的分布特点。受贺兰山、六盘山地形及区域降水量等因素影响，A 值低值中心位于银川市和石嘴山市，高值中心位于固原市南部地区。风速和混合层高度变化对宁夏大气环境容量A 值年代际演变趋势具有决定影响；降水和风速对其影响存在明显季节和地区差异，风速对北部春季A 值贡献较大，降水对中南部夏秋季A 值贡献较大。受冶金、火电、化工、建筑等高耗能产业和车辆排放影响，平罗县和利通区属于宁夏大气环境SO2、NOx临界及以下等级承载区，利通区以南各地为高承载区。
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