Subjects: Geosciences >> Atmospheric Sciences submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： To quantitatively evaluate the effect of meteorological conditions on air pollution, data from 14 meteorological sounding stations and surface observation stations in Xinjiang were used to analyze the spatial and temporal distribution characteristics of atmospheric self-purification capacity index (ASI) and air stagnation index (ASITS) from 2010 to 2020. Results showed a negative correlation between ASI and ASITS. ASI was the largest in summer and the smallest in winter. It was generally greater in southern Xinjiang than in northern Xinjiang, whereas ASITS showed the opposite trend. This implied that the atmospheric diffusion conditions were better in southern Xinjiang than in northern Xinjiang, and a static and stable atmospheric circulation more easily formed in northern Xinjiang than in southern Xinjiang. The daily pollution data of air environment monitoring stations from 2015 to 2020 were used to determine the correlation between the air quality of Xinjiang in different seasons and the air quality of five heavily polluted stations and the two indexes. The two indexes highly correlated with the air pollution data of Urumqi station, and the static stability index was better, which can well indicate the degree of air pollution. However, no good correlation was found between the two indexes and the air pollution data of four stations in the southern Xinjiang basin. In the heavy pollution case in the spring of 2018, the PM10 concentration span was very large, so the two indexes showed a high dispersion on the scatter diagram, which is not applicable. In particular, in Hotan and Aksu, the two indexes showed a certain correlation with the pollutant concentration, and ASITS performed better. In Kashgar, ASI showed no correlation with air quality, and ASITS showed a weak correlation; the two indexes showed no correlation with the air quality of Korla, implying poor applicability. Further study on the distribution of indexes under different pollution levels in the capital city of Urumqi showed that the early warning indicators can be preliminarily condensed as follows: When pollutant emission is serious, and if ASI is distributed at 0-20 t·(d·km2)−1, it is susceptible to heavy weather pollution, and the range of ASITS is of little significance.
Subjects: Geosciences >> Geography submitted time 2022-02-11 Cooperative journals: 《干旱区地理》
Abstract： 利用FY2E卫星资料，多普勒天气雷达产品，常规高空及地面观测数据和美国气象环境预报中心（NCEP，0.250.25）再分析资料，对2017年3月36日南疆西部一场极端暴雪过程进行综 合分析。结果表明：500 hPa中亚低涡是此次极端暴雪天气的影响系统。暴雪的水汽主要有3支输 送路径，分别是中高层的偏西、偏南和中低层的偏东路径。本次降雪具有冷季高架对流的部分特征：南疆盆地850~700 hPa冷空气东灌形成的偏东急流将南疆西部相对暖湿的空气抬升到一定高度，起到冷垫的作用；在卫星云图上，降雪云带内有黑体亮温（TBB）、尺度介于80~200 km 之间的中-尺度对流云团；雷达回波表现为层状回波中夹杂有块状回波，最大反射率>40 dBZ，回波顶高>6 km；进一步分析地转绝对动量（Mg）和假相当位温(se）发现，条件性对称不稳定导致的倾斜对流导致强降雪发生。
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