东南亚生物质燃烧对我国霾和降水的影响

基于生物质燃烧排放源清单、地面观测和数值模式对东南亚中南半岛生物质燃烧气溶胶的排放特征,以及其在2020年春季对我国云南地区霾天气和南方前汛期降水过程的影响进行了分析。结果表明:中南半岛生物质燃烧气溶胶排放主要集中于每年3—4月,排放峰值时段集中于3月下旬至4月上旬,主要排放区域为缅甸东部和老挝北部。中南半岛生物质燃烧气溶胶在地面主要影响我国云南南部城市的霾天气,缅甸的生物质燃烧气溶胶是最主要的贡献源。中南半岛生物质燃烧气溶胶在低空西南急流作用下,可以在800~600 hPa高度传输至我国华南和江南南部大部分区域上空。传输至我国南方上空的生物质燃烧气溶胶通过抑制对流性降水、增强非对流性降水,可以改变南方前汛期降水过程的空间分布,使降水更集中于切变线附近。

Effects of Biomass Burning Aerosol in SoutheastAsia on Haze and Precipitation over China

A fire inventory,surface monitoring data and numerical models were used to analyze the biomass burning aerosol(BBA)emission in Indochina Peninsula and its effects on haze in Southwest China and pre-monsoon precipitation in South China.The BBA emissions in Indochina Peninsula mainly occur in March and April every year,and the peak emissions appear in late March to early April.Eastern Myanmar and Northern Laos are the major regions of the BBA emissions.The BBA in Indochina Peninsula mainly affects the haze in the southern cities of Yunnan,China at the surface.The emission from Myanmar is the most significant contributor to the pollution in these cities.The BBA in Indochina Peninsula could be transported over most parts of Southern China by the low-level southwest jet at the height from 800 hPa to 600 hPa.The transported BBA over Southern China could alter the spatial fraction of the pre-monsoon precipitation process by suppressing the convective precipitation and enhancing the non-convective precipitation,and making precipitation more concentrated near the shear line.