An Observing System Sensitivity Experiment (OSSE) approach has been adopted to examine the impact of a range of Aerosonde reconnaissance modes on tropical cyclone forecasts. The procedure is to utilize the output from a very high resolution (5km) numerical model simulation of a tropical cyclone as the basic state, or reality, then to examine the impact of pseudo observations from a realistic deployment of Aerosondes on forecasts.
Using the northwest coast of Australia as the geographical location, observations are extracted from the numerical simulation at the times and locations of the current observing network. These data are then assimilated into the newly developed CEMAP data assimilation and prediction system. A 72 hour benchmark forecast is then made.
Next, a series of Aerosonde reconnaissance aircraft are deployed and observations taken along the flight track and re-inserted into the CEMAP assimilation and prediction system. Further 72 hour forecasts are then made and compared with the benchmark forecast.
By using the original model simulation as a basis, we are able to deploy the Aerosondes to take observations both in the cyclone core region and the periphery under realistic conditions. The results will be used to plan optimal Aerosonde deployment strategies in planned cyclone operations in this and other regions