中国区域CALIPSO和MERRA-2气溶胶三维参数对比验证

Comparison and verification of 3D parameters of aerosols between CALIPSO and MERRA-2 in China

气溶胶是目前大气污染重要的贡献源之一,影响着全球辐射平衡和气候变化。当前主被动遥感卫星(如MODIS和CALIPSO)获取全球气溶胶信息时间分辨率较低,而全球再分析数据MERRA-2提供了高时间分辨率的三维气溶胶分布信息,但是MERRA-2气溶胶产品的质量仍然有待验证。针对上述问题,通过对MERRA-2和CALIPSO的三维消光系数廓线进行交叉对比,验证了MERRA-2在中国中东部(特别是重人为污染区域)的数据精度。实验结果表明,MERRA-2和CALIPSO的消光系数整体具有较好相关性(0.79),其中二者在秋季相关性最高(0.82),夏季和冬季次之(0.81和0.80),春季相关性最低(0.77)。随着高度的不断增加,大气更为洁净,MERRA-2和CALIPSO之间相关系数从0.78降为0.52,标准差从0.0280降为0.0014。上述结果表明,MERRA-2在重污染情况下能提供更为准确的气溶胶三维分布信息,同时MERRA-2和CALIPSO消光系数的一致性受气溶胶类型的影响不大。

Aerosol is one of the important contribution sources of air pollution,which affects the global radiation balance and climate change.At present,active and passive remote sensing satellites(such as MODIS and CALIPSO)have relative low temporal resolution to obtain global aerosol information.MERRA-2,a global reanalysis data,can obtain high temporal resolution 3-D aerosol distribution,but the quality of MERRA-2 aerosol product is still need to be evaluated.Thus,this study verified the accuracy of MERRA-2 data in central and eastern China(especially in areas with heavy human pollution)by cross-comparing the three-dimensional profiles of extinction coefficient of MERRA-2 and CALIPSO.Results show that the extinction coefficients of MERRA-2 and CALIPSO have a good overall correlation(0.79),of which the two datasets have the highest correlation in autumn(0.82),followed by summer and winter(0.81 and 0.80),and the lowest correlation in spring(0.77).As the atmosphere becomes cleaner along with the altitude increasing,the correlation coefficient between MERRA-2 and CALIPSO declined from0.78 to 0.52,and the standard deviation declined from 0.028 to 0.0014.The above results demonstrate that MERRA-2 can provide more accurate 3-D aerosol information under heavy pollution.Meanwhile,the extinction coefficients of MERRA-2 and CALIPSO are not greatly affected by the type of aerosol.