The Spatial And Temporal Characteristics Of Chinese Cloud Water And Its Cause Based On The ERA-Interim

Cloud water is the direct source of precipitation,and its research can help us understand climate change better and reduce the uncertainty of cloud simulation in climate models.By using correlation,synthetic,and regression analysis methods,the spatial-temporal characteristics of cloud water in recent 38 a and the influence of large-scale atmospheric circulation and temperature on its interannual anomalies are analyzed.The results show that:(1)Cloud liquid water content and cloud water content in China are mainly located in the eastern part of Sichuan-Hunan,located at 850~500 hPa in the vertical direction.The large value of cloud ice water content is mainly located in the middle and eastern part of China(27°N~35°N,97°E~110°E),located at 500~250 hPa in the vertical direction.The small values are all located in the western part of the Northwest China.Cloud water in China has obvious inter-annual feature,its spatial trend is increasing in the west and decreasing in the east(boundary by 105 ° E).(2)Interannual anomaly of atmospheric circulation leads to the interannual variation of cloud water content in China: The anomalous increasing(weakening)water vapor flux derived from the westerly belt,the Baikal Lake and the South China Sea,combined with the convergence of Mongolia-Northeast anomalous cyclone strengthen(weaken),leads to the increase(decrease)of cloud water content in the northwest sub-region.The anomalous increasing(weakening)water vapor flux in the rear of the anomalous anticyclone in the East China Sea and cyclonic convergence over Mongolia strengthen(weaken),results in the increase(decrease)of cloud water content in the northern sub-region.The anomalous increasing(weakening)water vapor flux derived from the southern branch westerly belt,the west side of Tibet Plateau(referred to as TP)and Bay of Bengal,combined with the TP anomalous cyclonic convergence strengthen(weaken),leads to the increase(decrease)of TP cloud water content.The anomalous increasing(weakening)water vapor flux from the Arabian Sea,northwestern Pacific Ocean and the Yellow Sea,cooperating with the convergence of southern sub-region strengthen(weaken),increases(decreases)cloud water content in southern sub-region.(3)Under the global warming,the summer cloud water content in China is significantly positively correlated with temperature in the TP sub-region,and negatively correlated in other sub-regions.The specific influence mechanisms are as follows: The warming in the northwest sub-region weakens the water vapor flux of the westerly belt and the anomalous cyclone in the eastern Mongolia,the warming in the northern sub-region causes the anomalous cyclone in the Mongolia and the anomalous anticyclone in the southeast coast weaken,the warming in the southern sub-region weakens the abnormal cyclone in the Yellow Sea and the anomalous anticyclone in the South China Sea,the above changes are not conducive to water vapor flux transport and convergence uplift in low-level,further reduce the cloud water content.The warming of the TP sub-region strengthens the south branch of westerly belt,and lead to southward extension of the anomalous cyclone over the west of the TP,thus transporting more water vapor to the TP,further increase the cloud water content.