Verification of the Mountain Wave Forecast Model's Stratospheric Turbulence Forecasts Using Sounding Data and Pilot Reports

摘要

Since stratospheric turbulence (Stratoturb) is becoming an increased concern to the Air Force, the threat of damage to aircraft must be addressed. Therefore, the Air Force Weather Agency (AFWA) requests an accurate Stratoturb forecast model. In 2002, The Mountain Wave Forecast Model (MWFM) was modified in order to develop a Stratoturb forecast tool. Turbulence forecasts generated twice daily by the MWFM for locations over East Asia over a period of thirty days were compared to output from the Rawindsonde Observation (RAOB) program to determine if the model agreed with the program output. Although the results were promising, verification by aircraft crews flying through the stratosphere would improve the confidence of this forecast model, improving the forecaster s ability to warn pilots and alleviate the potential danger associated with flying through areas of Stratoturb. This thesis continues that research. Three major changes were made. Pilot reports (PIREPs) were collected for verification of MWFM forecasts, the model s time resolution was increased for better comparison to PIREPs, and data were collected for nearly a year to determine season performance. Model performance at ten sounding locations was analyzed to determine if performance improved over a certain terrain type. Model performance at three atmospheric levels (100-70mb, 70-50mb, and 50-30mb) was also compared to determine if the model performed better at a certain altitude. Results suggest that the MWFM is superior to previous methods of detecting Stratoturb. Therefore, the MWFM is recommended to AFWA for operational use.