基于卫星遥感的海南地区对流层NO_2长期变化及成因分析

Satellite-based long-term trends analysis in TroNO_2 over Hainan Island and its possible reason

利用OMI卫星反演的较高分辨率(0.125°×0.125°)对流层NO_2(Tro NO_2)柱浓度数据,分析了近12年海南岛TroNO_2柱浓度的时空变化,同时,结合MODIS卫星反演的气溶胶光学厚度(AOD)资料、海口市空气质量指数(AQI)、GDP、SO_2排放总量,以及民用汽车保有量等探究其长期变化与成因.结果表明:海南地区TroNO_2柱浓度空间分布表现为北半部高于南半部、四周沿海高于中部山区的特征,其中,北部地区最大值可达20×1014molec·cm^(-2)以上.近12年来海南地区TroNO_2柱浓度表现为上升的变化趋势.季节变化表现为冬季高于夏季,夏季浓度偏低和雨水的冲刷作用有关,而冬季偏高与旅游过冬人口增多和外源输送作用有密切联系.四季TroNO_2柱浓度均有不同程度的上升,而且季节差异在2010年以后有增大的趋势.海南地区TroNO_2柱浓度分布与岛上经济水平和人口分布关系密切,海南地区民用机动车拥有量近10年呈现快速的增加趋势,机动车尾气NO_2排放也不容忽视.

This study analyzes temporal-spatial characteristics of the tropospheric column NO2（ Tro NO2,resolution： 0. 125° × 0. 125°） over Hainan Island using OMI satellite data,and further investigates the possible reasons by using information on aerosol optical depth（ AOD）,AQI in Haikou city,GDP,total SO2 emissions,and the amount of private cars. It is found that Tro NO2 is larger in the north of Hainan Island,and is lower in the central mountainous area than the surrounding coastal regions. The maximum value in the north is 20 × 1014molec·cm^（-2）. Tro NO2 over Hainan Island shows an increase trend for the past 12 years,with higher value in winter than summer. The lower Tro NO2 in summer is related to more precipitation,while thelarger Tro NO2 in winter is attributed to increased tourism and outside transport. Since 2010,TroNO2 has been increasing for all seasons in association with an increase of the seasonal differences. Spatial distribution of Tro NO2 exhibits a close relationship with the population distribution over Hainan Island. In addition,with rapid increase in private car during the past 10 year,NO2 emissions of vehicle exhaust cannot be ignored.