青藏高原地区TSP分布特征及影响因素分析

摘要

利用大流量采样器采集了2002年11月～2009年8月的瓦里关山地区TSP样品,通过对数据的日、月、年和季节及后向轨迹等方法的分析处理,揭示了瓦里关山地区TSP基本特征及影响因素:2003～2008年TSP质量浓度多年均值为0.076mg/m3,呈下降趋势.TSP质量浓度的月际变化特征明显,从秋初开始逐步增大,至春季的4月出现峰值(多年平均值为0.195mg/m3),在5～8月的变化中,TSP质量浓度是逐渐下降,9月份达到浓度的最低值(多年平均值为0.029mg/m3);多年平均值在1～4月均超过国家标准环境空气质量一级标准.季节变化:春季最高,其次是冬季和秋季,夏季最低,四季的TSP平均质量浓度分别为0.148,0.091,0.037,0.035mg/m3,夏季呈下降趋势,其余季节呈上升趋势.TSP质量浓度明显受到局地气象因子降水量、温度、相对湿度、气压和风的控制.降雨量越小、温度越低、相对湿度越小、风速越小,大气TSP浓度越高,反之越低.春季背景大气TSP的质量浓度平均0.12mg/m3,大风天气为0.22mg/m3,浮尘天气为0.329mg/m3,扬沙天气0.382mg/m3,沙尘暴0.874mg/m3,分别为背景大气的1.8、2.7、3.2和7.3倍,雨雪的清除效率分别为33.9％和26.7％.气象后向轨迹模型分析瓦里关山地区沙尘暴的沙源地来源于新疆北部、甘肃西北部、内蒙古中西部及本省西北部的柴达木盆地.TSP质量浓度远低于城市和区域本底站,代表了全球大陆尺度的环境,冬春季多风沙是造成TSP质量浓度较高的主要因素.%This study revealed distribution characteristics and impact factors of TSP through backward trajectory and other analysis methods based on TSP samples collected by large flow sampler in November 2002 to August 2009 in Waliguan Mountain. TSP mass concentration of mean annual was 0.076mg/m2 and there was a downward trend in 2003 to 2008. TSP mass concentration increased from early autumn and reached the maximum in April and decreased from May to August and reached the minimum in September. Mean annual exceeded environmental air quality level 1 standard of National Standard. TSP mass concentration was in order of sping,winter,autumn,summer. Average TSP mass concentration of four seasons respectively was 0.148, 0.091, 0.037 and 0.035 mg/m2. Rainfall, temperature，relative humidity,pressure and wind effected on TSP mass concentration. TSP mass concentration was higher if the rainfall, temperature, relative humidity and wind speed was smaller. The average TSP mass concentration of background value, the gale weather, the floating dust weather, the sand-blowing weather and the sandstorm were 0.12,0.22,0.329,0.382 and 0.874mg/m3 in spring, respectively. The average TSP mass concentration of the gale weather, the floating dust weather, the sand-blowing weather and the sandstorm were 1.8,2.7,3.2 and 7.3 times of background value. The elimination efficiency of rain and snow were 33.9% and 26.7%. The sand sources of sandstorm in area of Waliguan Mountain was from Northern Xinjiang, northwestern Gansu, Midwest Area of Inner Mongolia and the Qaidam Basin through backward trajectory model analyzing. It represented global continental scales environment that TSP mass concentration was lower than cities and regional background stations, frequent wind and rich sand were main factors caused TSP mass concentration higher in winter.