%0 Journal Article
%T Reconstruct the Mesoscale Information of Typhoon with BDA Method Combined with AMSU-A Data Assimilation Method
%A Yunfeng Wang
%A Haiyang Zhang
%A Bin Wang
%A Yueqi Han
%A Xiaoping Cheng
%J Advances in Meteorology
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/346516
%X This paper conducts the assimilating experiments and simulating experiments on typhoon ˇ°Aereˇ± (No. 0418), by use of bogus data assimilation (BDA) method combined with advanced microwave sounding unit-A (AMSU-A) data assimilation method in the fifth-generation National Center for Atmospheric Research (NCAR)/Penn State Mesoscale Model Version-3 (MM5V3), the Radiative Transfer for TIROS-N Operational Vertical Sounder Version-7 (RTTOV) model, and their adjoint models. The Bogus data constructed with BDA technique are mainly located at sea level, while the peak energy contribution levels of the sounder channels selected in AMSU-A data assimilation technique are mainly located at upper troposphere. The two types of data can reconstruct the meso-scale information and improve the typhoon initial fields under the model dynamic forcing effect, respectively from the low level and the upper level of atmosphere during the assimilating process. Numerical results show that with four-dimensional variational data assimilation (4DVAR) technique the circulation of initial fields is improved, the ˇ°warm coreˇ± of typhoon is enhanced, the ˇ°cloud waterˇ± phenomenon that occurs in the optimal initial fields and the numerical model is changed into ˇ°warm startˇ± from ˇ°cold startˇ±. 1. Introduction Typhoon is one of the most frequent disasters affecting human beings. With the development of numerical forecasting techniques, numerical forecasting of typhoon has entered an operational stage. However, the prediction accuracy is far from meeting the requirements of disaster prevention and reduction. If the track and intensity of typhoon can be accurately forecasted, necessary preparedness can be performed beforehand and serious economic loss can be much reduced. Due to severe deficiency of conventional observation data over sea, the results of objective analysis can not precisely describe the thermal structure and circulation characteristics of initial typhoon, especially its mesoscale structure, which is one of the main reasons for serious errors in typhoon numerical forecasting. Therefore, how to provide more rational initial values is an urgent task. Since 1990s, an initializing method of artificial typhoon mode is introduced into typhoon forecasting research [1¨C3]. With this method, an ideal bogus typhoon mode with 3-dimensional circulation structure and thermal structure is constructed according to the observation data, and then it is implanted into the initial typhoon analysis fields to construct new initial typhoon optimal fields. This method is now widely applied in Typhoon
%U http://www.hindawi.com/journals/amete/2010/346516/