西宁市区不同天气形势下的PM_(10)输送路径及潜在源区

针对2016年西宁市区稳定和沙尘两种不同天气形势,基于后向轨迹气团的聚类分析法、潜在源贡献因子法(PSCF)和浓度权重轨迹分析法(CWT),结合市环境监测站PM_(10)浓度质量资料,分析了西宁市区不同天气形势下不同来源区域PM_(10)质量浓度的贡献影响及其潜在源区。结果表明:西宁市区稳定天气PM_(10)均来自青海省境内,PM_(10)输送路径以西方和东方转向路径最多,占总轨迹数的34.78%和30.43%;西方路径主要从青海省格尔木市向东输送,东方转向路径则从西宁市西部地区向东转而向西输送,两者经过的地区均没有明显的沙源;PM_(10)的潜在贡献源区主要在西宁市区及其北部与大通县和互助县交界地区。沙尘天气PM_(10)输送路径除了以来自青海省海西州的西方路径为最多外,甘肃省河西走廊的东方转向路径也较多,占比分别达到42.11%和36.84%;西方路径PM_(10)主要从沙漠地带南疆—青海省海西州西部向东输送,东方转向路径PM_(10)则经河西走廊沙源地进入西宁市区;PM_(10)污染主要是PM_(10)由沙源地输送进入西宁市区聚集所造成。地形对PM_(10)的输送路径有较大的影响。

Transportation Path and Potential Source of PM10 in Xining City in Different Synoptic Situations

Using cluster analysis method, potential source contribution factor method (PSCF) and concentration weight trajectory analysis method (CWT) based on backward trajectory model in stability and sand synoptic situation in 2016 of Xining city, combining with environmental monitoring station measured PM10 concentrations, the influence of different source areas on the PM10 concentration contribution during different synoptic situations of Xining city and its potential source are studied. The results are as follows. The PM10 during stability synoptic condition are all from Qinghai province, the western and eastern turn direction of transportation routes are most frequently involved, accounting for 34.78% and 30.43% respectively of total backward trajectories, and the western direction mainly transport eastward from Golmud city of Qinghai province and eastern turn direction mainly transport eastward from western region of Xining and then turn westward, there are no obvious sources of sand in either transporting path. The potential source contribution of PM10 is in Xining city and the area between northern Xining city, Datong and Huzhu. The PM10 in sand synoptic condition are also from Hexi Corridor of Gansu province except Qinghai Haixi state as the most, the ratios are 42.11% and 36.84% respectively, the western direction mainly transport eastward from desert land in southern region of Xinjiang province and western Haixi state of Qinghai province, and eastern turn direction turn from sand source regions in Hexi Corridor to Xining city, and PM10 heavy pollution events are caused by local particle aggregation from sand source regions. The terrain has a great influence on the transport path of PM10.