A Study of the Impact of Airborne Radar Data Assimilated by 3DVar on the Prediction of Hurricane-Isaac 2012

Given the increasingly important role of inner-core data in tropical cyclone(TC) forecasting, the present paper investigates the impact of assimilating Tail Doppler Radar(TDR) data on the prediction of hurricanes. A series of experiments are conducted using the operational Weather Research and Forecasting model for Hurricane(HWRF) and grid-point statistical interpolation(GSI) 3D variational(3DVar) system for Hurricane Isaac(2012). It is found that the assimilation of TDR data can correct the storm center to a better position compared to without TDR assimilation. Furthermore, the better inner-core structures in the results of the experiments that assimilated the TDR data have a positive impact on the intensity forecasts. In general, the TDR data improve the TC track and intensity forecast compared to the official forecasts from the operational HWRF, and the forecasts without assimilating the TDR data. The study also suggests that further reducing the background error covariances to be consistent with the dynamical and thermodynamical structures of the hurricanes is needed to further improve analyses and predictions of TCs.