An observation system simulation experiment of WISDOM balloon data using the target technique

We've used the NOAA's Joint OSSE system to estimate the impact of WISDOM balloon data launched from some existing radiosonde station sites on hurricane track forecasts. The result indicated that the improvement of track is not significant even we assimilated thousands of balloon data. One possible improvement of the WISDOM data impact would be considering launch balloons from targeted observation areas. In this study, we will use ETKF (ensemble transform kalman filter) technique to estimate data sensitive areas and apply this scheme in the OSSE system. We will re-evaluate the WISDOM data impact on hurricane tracks using this targeting observation technique. The outcome of this study may provide a future WISDOM balloon launching strategy.