Synoptic Weather Patterns Modulate The Frequency, Type And Vertical Structure Of Summer Precipitation Over Eastern China: A Perspective From Gpm Observations

Precipitation is one of the most important features of the weather in the East Asian monsoon climatic zone; however, the ways in which different synoptic weather patterns modulate the three-dimensional structures of precipitation are yet to be fully understood. Taking the example of eastern China and using the three-dimensional observations of precipitation measured by the dual-frequency precipitation radar onboard the Global Precipitation Measurement mission during 2014-2018, this study explores the rain rate (RR), precipitation frequency (PF), and vertical characteristics of precipitation during summer under four synoptic weather patterns (SWPs) objectively classified using reanalysis data. The four SWPs are referred to as Type 1, 2, 3, and 4. The RRs, PFs, and vertical structures over eastern China are closely linked to the variations of these four large-scale SWPs related to the western Pacific subtropical high (WPSH) and exhibit remarkable regional disparities. The highest PFs of stratiform, convective, and shallow convective precipitation over the whole of eastern China occur under Type 1, followed by Type 2. To the south of 40 degrees N, a more intense RR for both stratiform and convective precipitation appears under Types 1 and 2, while to the north of 40 degrees N these features appear under Types 3 and 4. The Contoured Frequency by Altitude Diagrams for both convective and stratiform precipitation exhibit large positive anomalies of large-value radar reflectivity above (below) 5 km over most regions under Types 2 and 4 (Types 1 and 3). Meanwhile, large positive anomalies for most regions occur under Types 3 and 4 for shallow convective precipitation and are mainly concentrated below the altitude of 4 km. These differences in vertical structures under different SWPs depend mainly on various vertical movements and water vapor moisture supplies related to the location of the WPSH. Our findings provide evidence of a possible linkage between the threedimensional features of convective, shallow convective, and stratiform precipitation and large-scale WPSH circulation on the synoptic scale.