Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-27 Cooperative journals: 《干旱区地理》
Abstract： Research has confirmed that the global terrestrial vapor pressure deficit (VPD) has already increased and will continue to increase. In this context, it is worth exploring whether the atmospheric environment in Xinjiang of China tends to be drier. The VPD series of Xinjiang from 1961 to 2020 was calculated based on meteorological observation data. Then, the distribution and spatio-temporal evolution characteristics of VPD were studied by linear trend analysis, Mann-Kendall test, etc. The results are as follows: (1) From 1982 to 2015, the average annual VPD in Xinjiang exhibited an obvious upward trend with an increased rate of 0.015 kPa·(10a)−1 . As shown in the Mann- Kendall test, an abrupt change in VPD occurred around 2005, and a weakly fluctuating change was observed before the mutation, followed by an increasing trend. (2) There were significant differences in the intensity of VPD in different seasons, but increasing trend changes, even though the rates of increase differed, which appeared in the series of mean VPD values for each season. In comparison, the magnitude of increase in VPD sequences was greater in spring and summer and the smallest in winter. The characteristics of abrupt changes in VPD sequences in spring and autumn were relatively consistent with the changes in the annual VPD value series, whereas summer was slightly later, with the abrupt change that occurred in 2006. (3) Spatially, VPD exhibited a distinct difference of“low in the mountains and high in the basins”, and there was spatial heterogeneity in its long-term evolution trend. A large area of the entire territory (approximately 83.65% of the meteorological stations) exhibited an increasing trend in VPD, whereas the stations with decreasing trends were mostly distributed in the northern foothills of the eastern part of the Tianshan Mountains and the northern/ northwestern edge of the south Xinjiang Basin. On the seasonal scale, the number of meteorological stations with increasing trend changes in VPD in spring accounted for the highest proportion of the total number of stations (96.15% ), indicating that this season is the most extensive period of VPD in Xinjiang. Comparatively, the relatively small variation of the VPD time series showed that the atmospheric dryness during winter in Xinjiang was relatively stable in the long term. This study reveals the evolution of VPD in Xinjiang under a significant shift from warm-wet to warm-dry and serves as a reference for reducing uncertainties in the prediction of changes in ecosystem structure and function
Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-02-02 Cooperative journals: 《干旱区地理》
Abstract：选用20002019年11月次年3月塔城地区7个国家气象观测站逐日降水、温度、常规地面和高空观测资料、美国国家环境预报中心（NCEP）再分析资料，确定近20 a塔城地区暖区暴雪天气过程并进行分析。结果表明：（1）塔城地区暖区暴雪发生于塔额盆地的塔城站、裕民站和额敏站，塔城站出现频次最多；时间分布上，11月和12月出现暖区暴雪的频次最高，且主要集中在11月中旬12月上旬，1月次之，2月最少。（2）塔城地区暖区暴雪分为3类：低槽前部型、横槽底部型和西北急流型，地面低压为西方和西北路径。低槽前部型是最典型的暖区暴雪形势，主要出现在11月12月上旬，发生在西西伯利亚低槽前部锋区与南支中纬度短波槽汇合区，地面低压为西北路径；横槽底部型主要出现在11月次年1月，发生在极锋锋区底部偏西气流和中纬度暖湿西南气流汇合的强锋区中，地面低压为西方路径；西北急流型主要出现在1112月，发生在极锋锋区西北气流中，地面低压为西北路径。（3）500~300 hPa强西北或偏西急流、700 hPa偏西低空急流、850 hPa暖式切变的叠置区与暖区暴雪落区一致，低槽前部型和西北急流型为锋前暖区产生暴雪，横槽底部型为低压右前部暖锋锋生产生暴雪。（4）低槽前部型和横槽底部型的水汽均为偏西路径，来自地中海、阿拉伯海的水汽经里海、咸海增强后向暴雪区输送；西北急流型有偏西和西北2条水汽输送路径，来自高纬度巴伦支海的水汽与来自中低纬度里海、咸海、地中海、阿拉伯海的水汽在巴尔喀什湖附近汇合后向暴雪区输送，较强的水汽输送伴随低层明显的水汽辐合，强辐合中心位于850~700 hPa之间。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2022-10-21 Cooperative journals: 《干旱区地理》
Abstract：利用常规地面、高空观测资料、NCEP/NCAR 11再分析和FY卫星资料，针对乌鲁木齐 1990年以来的3场典型暴雪天气，从高低空环流和天气系统配置、不稳定条件、水汽、动力及黑体亮 温（TBB）变化等方面综合对比分析暴雪成因。结果表明：（1）3场暴雪均发生在欧洲高压脊东南衰 退，推动西西伯利亚低槽东移南下，与中纬度短波槽结合的环流形势下，高低空系统呈后倾槽结 构，乌鲁木齐处在925~600 hPa西北急流与600~200 hPa强西南急流叠置区，且天山山脉的地形强 迫抬升有利于暴雪的维持和加强。（2）暴雪前850~700 hPa均有东南风存在，微差平流作用有利于 平流逆温生成和加强，使得能量不断积聚，后期冷空气进入，冷锋锋生，层结不稳定发展，为暴雪天 气提供热力条件，东南风和平流逆温维持时间越长，储存能量越多，降雪越强。（3）暴雪区存在西南 和偏西2条水汽输送通道，中层水汽输送对乌鲁木齐暴雪至关重要，850~600 hPa存在较强的水汽 辐合，且700 hPa最强。水汽输送、辐合强度及持续时间共同决定暴雪强度。（4）TBB与降雪强弱有 一定的对应关系，TBB越低，云顶高度越高，中尺度云团发展越旺盛，降雪越强，降雪前TBB（云顶高 度）的第一次迅速降低（升高）预示降雪开始，降雪过程中TBB降低对应降雪强度增强，且TBB降幅 越大、低TBB值维持时间越长，降雪越强。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2022-01-21 Cooperative journals: 《干旱区地理》
Abstract：利用20102019年新疆14个探空气象站资料统计分析了近10 a大气最大混合层高度（下文简称混合层高度）、通风量、边界层平均风速及大气自净能力指数的时空分布特征，探讨了各物理参数与空气质量的关系。结果表明：（1）以上参数的逐月分布均呈倒V型，表现为夏半年大、冬半年小，即新疆的大气扩散能力在夏季最强、冬季最弱，其中混合层高度和通风量在冬、夏季差距悬殊。（2）南疆大气扩散能力普遍比北疆好，无论冬夏南疆的自净能力、通风量、混合层高度均大于北疆。（3）北疆除阿勒泰站外，其余站点上述物理参数均与空气质量指数（Air quality index，AQI）呈显著负相关，即大气扩散能力越强，空气质量越好，而南疆只有和田站通过了0.01的置信度检验，但两者呈正相关，即大气扩散能力越强，空气质量越差，这归因于南北疆不同的大气污染来源。
Subjects: Geosciences >> Geography submitted time 2021-04-23 Cooperative journals: 《干旱区研究》
Abstract：利用2000—2019年新疆升温融雪（冰）型洪水灾情资料，分析了近20 a融雪（冰）型洪水频次的时空分布和地域差异性，结果表明：北疆融雪型洪水频次占全疆的75%，主汛期在春季，集中出现在北疆西部北部区域，伊犁哈萨克自治州最多（新源县最多）；南疆主汛期在夏季，融雪（冰）型洪水主要出现于昆仑山北坡，3月和7月是北疆融雪和南疆融雪（冰）型洪水的高发月份。20 a来南北疆春季融雪型洪水频次均呈增多趋势，后10 a融雪（冰）型洪水频次较前10 a均增多，增幅30%左右。阐明了新疆融雪（冰）型洪水的天气学分型，分析了伊朗副高东扩型、西太副高西伸型和新疆脊发展型三类大气环流形势，给出新疆升温融雪（冰）型洪水的高低空环流形势及天气系统配置。得出融雪（冰）型洪水发生前，100 hPa南亚高压呈单体型，100～700 hPa新疆受深厚高压脊控制，高空0 ℃层高度明显偏高，前期山区降水明显偏多。北疆需重点防范春季伊犁州的中低山体季节融雪型洪水，南疆则应密切关注夏季高山冰湖溃决型和积雪、冰川融水型两类融雪（冰）型洪水。
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