Comparison of Synoptic Circulations of Heavy Rain Associated with Typhoons Meari and Muifa over Liaodong Peninsula

Tropical cyclones(TC) Meari(1105) and Muifa(1109) had similar tracks and caused severe rainfall over Liaodong Peninsula. However, Meari produced heavy precipitation with a much longer time period, although with weaker intensity, than that of Muifa. Using the Tropical Cyclone Yearbook, Fengyun(FY_2D) 0.1°×0.1° cloud top brightness temperature data, hourly rainfall observations from Dalian automated weather station, conventional observational data, and National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis data, the two TC cases that affected Liaodong Peninsula were compared and diagnosed. The results showed that(1) Meari had relatively weak intensity when affecting Liaodong Peninsula; however, it decayed slowly due to abundant moisture supply from the low-level southeast jet. Muifa was stronger than Meari, but its strength decreased rapidly due to the cut-off with the low-level moisture jet.(2) Meari and Muifa experienced extratropical transition when approaching westerly troughs. However, they possessed different structures when affecting Liaodong Peninsula:Meari had a hybrid structure with remarkable baroclinic instability, and mesoscale convection developed on its north side; while Muifa transformed into a cold core in low-level circulation and its cloud structure showed isolated features.(3) One of the causes of the difference in precipitation amount over Liaodong Peninsula was their different locations in the typhoon circulation. Liaodong Peninsula was located in the north of Meari, possessing strong low-level convergence, vertical wind shear, and deep and persistent vertical motion. However, its location was in the west of Muifa, where the northerly wind produced downward motion and dynamic lifting was reduced.