Tropical cyclone formation within strong northeasterly environments in the south china sea
Journal
Atmosphere
Journal Volume
12
Journal Issue
9
Date Issued
2021
Author(s)
Abstract
In the South China Sea (SCS), 17% of tropical cyclones (TCs) formed in the late season (November?January) were associated with a strong northeasterly monsoon. This study explores the effects of northeasterly strength on TC formation over the SCS. The Weather Research and Forecasting (WRF) model is used to simulate the disturbances that develop into TCs (formation cases) and those that do not (non-formation cases). Two formation (29W on 18 November 2001 and Vamei on 26 December 2001) and two non-formation (30 December 2002 and 9 January 2003) cases are simulated. To address the importance of upstream low-level northeasterly strength to TC formation, two types of sensitivity experiments are performed: formation cases with increased northeasterly flow and non-formation cases with decreased northeasterly flow. If the strength of the northeasterly is increased for the formation case, the stronger cold advection reduces the convective instability around the disturbance center, leading to the weakening of the simulated disturbance. If the strength of the northeasterly is decreased for the non-formation case, the simulated disturbance can develop further into a TC. In summary, strength of the upstream low-level northeasterly flow does affect the environmental conditions around the disturbance center, resulting in the change of TC formation probability over the SCS in the late season. ? 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Subjects
Environmental conditions
Late season
South china sea
Tropical cyclone formation
Winter northeasterly monsoon flow
Hurricanes
Storms
Tropics
Convective instabilities
South China sea
Tropical cyclone
Weather research and forecasting models
Weather forecasting
computer simulation
environmental conditions
monsoon
tropical cyclone
weather forecasting
winter
Pacific Ocean
South China Sea
Type
journal article