Analysis of characteristic of a heavy rainfall in northeast Hubei induced by high-altitude cloud wave

Abstract

Using observational data, GFS reanalysis data and high spatial and temporal resolution FY satellite data, we analyzed the relationship between the heavy rains in northeast Hubei at 16:00 BT on 30 June 2016 and the cloud wave originated from southwest vortex center 400 km away from eastern of Hubei at 08:00 BT. It is found that two gravity waves near the southwest vortex precipitation propagate north and east, before the occurrence of heavy rain in eastern of Hubei. The north-transmitted cloud wave propagated southeastward after triggering strong precipitation in northwestern Hubei. The north-turning branch cloud wave was affected by the 500 hPa symmetry instability which caused cloud wave, but the 500 hPa water vapor was not good for precipitation formation. The south branch cloud wave is affected by conditional convective instability below 600 hPa, and appears weak inertial gravity wave propagation. After the intersection of the two north and south cloud waves in different heights, shallow convection turns to deep convection. Under sufficient moisture and unstable conditions, local heavy precipitation in eastern Hubei was triggered.

Keywords

• southwest vortex
• cloud wave
• gravity wave
• strong precipitation