京津冀晋鲁区域气溶胶光学厚度的时空特征

Spatio-temporal characteristics of aerosol optical depth over Beijing-Tianjin-Hebei-Shanxi-Shandong region during 2000—2013

利用2000年3月至2013年12月MODIS Level 3遥感反演大气气溶胶光学厚度(AOD)产品数据,分析近年来京津冀晋鲁区域AOD的时空分布和变化特征.结果表明:1从时变特征来看,近14年来全区年平均AOD值在0.428~0.550之间变化,年际间变化浮动大,因此多年平均增长率并不高,仅呈微弱增长趋势;以2008年为界可将近14年的AOD变化分为呈明显上升趋势的第一阶段(2000—2007年,增长率为1.349%)以及呈明显下降趋势的第二阶段(2008—2013年,增长率为-1.483%);全区四季AOD多年变化除夏季呈微弱下降趋势,其它3季均为上升趋势,冬季增长率最大;夏季AOD最高,但有回落的趋势,冬季AOD最低,但有上升的趋势.2从空间分布特征来看,全区多年AOD空间分布大体上呈南高北低的格局,河北和山东的西南部为高值区(AOD为0.72),河北和山西的北边为低值区(AOD为0.23),北京和天津则处于中上水平(AOD为0.58);全区四季AOD空间分布呈现出强烈的季节变化,春季较高,夏季最高,进入秋季显著降低,冬季则最低,冬季到来年春季呈跳跃性增高.这些结果有助于京津冀晋鲁区域的气候变化和环境研究.

Based on the monthly data of MODIS Level 3,the spatio-temporal variations of Aerosol Optical Depth( AOD) over Beijing-Tianjin-HebeiShanxi-Shandong region from March 2000 to December 2013 have been analyzed. The results showed that: 1 the areal annual mean AOD varied between0. 428 and 0. 550 for the whole region during 2000—2013,and increasing but not significant trends occurred in the past 14 years due to the greatly interannual variations. The AOD variations over the past 14 years can be divided into two stages,the first increasing stage from 2000 to 2007 with an increase rate of 1. 349% and the second decreasing stage from 2008 to 2013 with a decreasing rate of 1. 483%. Increasing trends can be found in spring,autumn and winter and the greatest increasing trend appeared in winter; the mean AOD was the highest in summer but had a decreasing trend,while the mean AOD was the lowest in winter but had an increasing trend. 2 the areal annual mean AOD of the past 14 years presented a layout of high in south and low in north; Southwest Hebei and Shandong had high value with an AOD of 0. 72,north Hebei and Shanxi had low value with an AOD of 0. 23,while Beijing and Tianjin were above the average with an AOD of 0. 58; the seasonal characteristics showed that the mean AOD was the highest in summer,decreasing gradually from summer to winter and bouncing back next spring. These results are useful to further investigation of regional climate change and air pollutionvariation in northern China.