Airborne Doppler Wind Lidar data impacts on tropical cyclone track and intensity forecasting: the data processing, interpretation and assimilation

In 2008, a Doppler Wind Lidar (DWL) was flown on a Navy P3 aircraft as part of the TPARC and TCS08 investigations. This was the first time a DWL was flown over an extended period of time (2 months) with a goal to focus upon the genesis and evolution of tropical cyclones (TC). Prior to the experiment, there were reservations regarding the use of an optical remote sensing instrument like the DWL within the cloudy environment of developed TCs and the utility of wind profiles constructed from data taken from a moving platform over several kilometers. As shown by Pu (2010), early use of DWL wind profiles near Typhoon Nuri showed significant impacts on storm track and intensity predictions using the WRF model. As more of the P3DWL data from TPARC has been processed, additional improvements to the product have been made. Data processing algorithms have been written to: accounting for returns from hydrometeors, account for strong returns from the water surface and the adjacent air (in motion), and correct for large platform motions. These algorithms and improved processing have resulted in a significant reduction in wind speed and direction errors and have improved the confidence in the wind profiles for diagnostic and predictive applications. We will present summary results from extensive comparisons with dropsondes and demonstrate how the DWL curtain of wind profiles can be used to assign representativeness errors for the wind, temperature and moisture information provided by the dropsondes in the data assimilation systems used in NWP.