甲烷分布差异和含量变化对突发性暴雨的影响机理

Influence Mechanism of Methane Distribution Difference and Content Change on Abrupt Rainstorm

突发性暴雨对国民经济和人民生活危害严重,传统的天气图分析及数值模式等预报方法很难对突发性暴雨进行准确预测。甲烷是一种对于地气系统的能量平衡和大气成分的转化有重要影响的温室气体,甲烷含量的明显变化增加了大气的不稳定性,有助于产生强对流天气。为了研究甲烷含量对突发性暴雨的影响机理,针对南京市2017年6月初突发的暴雨事件,利用Aqua极轨卫星上大气红外探测器(atmospheric infrared sounder,AIRS)的甲烷日产品,对甲烷含量与突发性暴雨的关系进行了分析,发现突发性暴雨发生前1~2 d,甲烷含量日变化剧烈,有极大值出现,当强降水产生时则变为极小值。甲烷含量变化影响了局地的大气结构,增强了大气热力的不稳定,为暴雨的发生提供了有利条件。甲烷含量与突发性暴雨的显著相关性,为暴雨预报提供了新的视角。

Abrupt rainstorm has an inestimable impact on the national economy and people s lives.However,it is very difficult to accurately forecast abrupt rainstorm with the weather chart analysis and numerical model prediction methods.Methane is a greenhouse gas that has an important impact on the energy balance of the ground-air system and the transformation of atmospheric components,and the obvious change in methane content increases the instability of the atmosphere that can help to produce strong convective weather.In order to study the effect mechanism of methane content on abrupt rainstorm,aims at the abrupt rainstorm in early June of 2017 in Nanjing with the methane daily inversion product retrieved by AIRS sensor on Aqua polar orbit satellite.It is found the methane content obviously increases in 1~2 d ahead of abrupt rainstorm,the daily variation of methane content always reaches to a maximum value,when the abrupt rainstorm is produced,the methane content becomes a minimum.The change of methane content affects the local atmospheric structure,enhances the atmospheric instability,and provides favorable conditions for the occurrence of rainstorm.The significant correlation between the methane content and abrupt rainstorm provides a new view for rainstorms prediction.