Abstract:

Using the reanalysis data of FNL (Final Reanalysis Data) and GDAS (Global Data Assimilation System) from the NCEP (National Center for Environmental Predictions), the precipitation data from China Meteorological Observation Network and the results of HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model based on the Lagrange method, the water vapor conditions and transport process of a rainstorm triggered by a weakening typhoon in Northeast China from August 13 to 17, 2019 were analyzed.The results show that the water vapor in Northeast China is most closely related to the water vapor from the Western Pacific Ocean.Typhoon "Lekima" is the main water vapor supply system for this rainstorm, followed by Typhoon "Krosa".There are three main water vapor transport sources in the Lagrange method, which come from the western Pacific in the middle and low latitudes, respectively, corresponding to the Pacific and Yellow Sea in the Euler method.It originates from the South China Sea and corresponds to the Indian Ocean.Water vapor from northern Heilongjiang and northern China also plays a role in the rainstorm.The southern water vapor in the South China Sea and the western Pacific merge, which is the main water vapor supply for the rainstorm in Northeast China.The water vapor budget is mainly concentrated in the middle and lower layers, and the convergence zone of water vapor is mainly located between 700~900 hPa.The water vapor in the lower layer is transported vertically to the upper layer, and the stronger the water vapor convergence and vertical transport, the greater the precipitation.The water vapor inflow concentrates on the southern boundary of the lower layer, while the western and northern boundaries are generally the water vapor outflow boundary.

Key words: Typhoons, Rainstorm, HYSPLIT, Water vapor