基于OMI数据的兰州地区吸收性气溶胶指数时空分布特征研究

基于OMAERUV遥感数据产品,对兰州地区2008—2017年紫外吸收性气溶胶指数(ultraviolet aerosol index,UVAI)的时空分布进行了分析,并对其变化相关因素进行了探讨,结果表明:兰州地区2008—2017年UVAI整体呈上升趋势,年均值增幅为7.0%,2008—2010年UVAI出现了最大增长率53.1%,2011—2015年UVAI出现了最大降低速率18.5%,2016—2017年UVAI在2015年的基础上继续下降,2017年有所上升.2008—2017年兰州地区UVAI的空间分布特征为中间高、东西两侧低.10年来研究区UVAI最高值一直为永登县和皋兰县结合部及相邻区域,也是吸收性气溶胶的污染源中心.每年的最高值出现在1—2、11—12月,10年中最大的UVAI值出现在2017年的12月,每年的最低值出现在6—7月,10年中最低的UVAI值出现在2017年6月,四季UVAI值水平为:冬季春季秋季夏季.影响因素中UVAI与自然要素中的风向、温度和降水关系密切,兰州各地区的人口密度也与UVAI的变化具有相关性;基于PM_(2.5)的UVAI指示的空气质量等级分析,兰州地区空气质量以良为主.针对兰州地区UVAI的时空分布特点、吸收性气溶胶外源和内源污染源情况,提出了在永登县北部区域建设防护林带、减少人为活动强度等建议.

Temporal and spatial distribution of absorbing aerosols index in Lanzhou based on remote sensing data

Based on OMAERUV remote sensing data products, this study analyzed the spatial-temporal distribution of ultraviolet aerosol index (UVAI) in Lanzhou area from 2008 to 2017, and the influencing factors were discussed. Results showed those:from 2008 to 2017, the overall UVAI trend an increased with an annual average increase of 7.0% per year. The maximum annual average increase of UVAI was from 2008 to 2010 was 53.1%.The maximum annual reduction of UVAI was 18.5% from 2011 to 2015. From 2016 to 2017, the UVAI continued to decline and increased again in 2017. The spatial distribution of UVAI in this area showd a characteristic that UVAI in the middle area was high while it in the sides was low. In the past 10 years, the highest values UVAI in the study area was in the joint department of Yongdeng County and Gaolan County, which was also the center of the absorbent aerosols pollution sources. The highest value of UVAI occurs in January to February and November to December each year, and highest value of UVAI over the past 10 years appeared in December 2017. The lowest value of UVAI in each year appears in June to July and the lowest value of UVAI in the past ten years appeared in June 2017. The UVAI in the four seasons was in the order:Winter > Spring > Autumn > Summer. UVAI is closely related to wind direction, temperature and precipitation and the population density. The PM_2.5-based UVAI data showed that the air quality was good in general. According to the spatial-temporal distribution characteristics of UVAI in Lanzhou and the sources of external and endogenous pollution of absorbent aerosols, this study proposes to construct protective forest belts in northern Yongdeng County to reduce the intensity of human activities.