|Title||An assessment of using dropsonde data in Numerical Weather Prediction|
|Publication Type||Technical memorandum|
|Secondary Title||ECMWF Technical Memorandum|
|Place Published||Shinfield Park, Reading|
In this paper the use of wind and temperature profiles from dropsonde observations in the analysis and forecast has been studied in different contexts. Dropsondes have been deployed in three measurement campaigns: FASTEX (February 1997), NORPEX (February 98) and the Tropical Cyclone campaign (summer 1998). In FASTEX and NORPEX dropsondes were released in sensitivity areas where errors in the initial state are fast-growing, in order to monitor data-sparse areas where storms are generated and evolve. The impact study results show a reduction of the 2-day forecast error over the forecast verification areas: west coast of North America for the NORPEX and west of England (over the North Atlantic) for the FASTEX measurement missions. Moreover, a positive impact has been found over the North Atlantic and Europe (FASTEX) and Europe and the Northern Hemisphere (NORPEX) in the medium range forecast. In the Tropical Cyclone campaign, deployed dropsonde observations in the hurricane region have been found to improve the analyzed structure of the tropical cyclones and to give a better forecast in terms of track and mean wind speed of the hurricane.