Sensitivity of a simulated landfalling typhoon to soil moisture initialization

Landfalling typhoons over the Korean Peninsula often result in tremendous damage along with heavy rainfall and strong winds. Typhoon intensity is affected by surface feedback mechanisms both over land and water. Therefore, the focus of this study is the influence of surface conditions on landfalling typhoons in numerical simulations.

In order to investigate the effects of soil moisture initialization on a landfalling typhoon, numerical model simulations, using the Weather Research and Forecasting (WRF) model, are conducted. Typhoon Ewiniar's landfall over the Korean Peninsula on June 2006 is investigated in this study. Multiple values of soil moisture (CTRL, DRY, WET) are used as initial surface conditions during these sensitivity tests. The experiment involving initial soil fields derived from KLDAS (the Korea Land Data Assimilation System), which was constructed in order to improve surface initial data over East Asia, is also conducted in an attempt to examine the dependence of typhoon simulations on initial soil conditions. The amount and distribution of precipitation around the center of typhoon Ewiniar is significantly affected by the variation of soil moisture.