JP2.4
Verification of MM5 Cloud Microphysics Schemes for East Asia
Dean James Carter, Air Force Institute of Technology, Wright-Patterson AFB, OH; and R. P. Lowther
This research compares biases of the Reisner Mixed-Phase Explicit Moisture Microphysics graupel (Option 7) and non-graupel schemes (Option 5) to determine if including graupel and riming processes within the Fifth Generation Mesoscale Model (MM5) will lead to improved forecasts of winter precipitation over Korea and Japan. The main purpose of this research was to make a recommendation to Air Force Weather Agency (AFWA) as to whether a more computationally expensive scheme is better suited for the East Asian theater. The ultimate goal is to find a way to reduce the negative impact winter precipitation places on military operations and public safety. To explore the biases of these two Reisner schemes, MM5 forecasts were generated every 12 hours for a 20-day case period within January 1998. Gridded meteorological fields were interpolated to the station coordinates of four verification sites within the East Asian domain and radiosonde observations were used to compare the differences between the average temperature and water vapor errors of the two cloud microphysics schemes. Various scores were used to compare the success of the two Reisner schemes to categorically forecast precipitation type at the surface. Analysis of the results shows significant differences between the schemes in the magnitude of humidity errors within the lower atmosphere of the model and provides evidence that the more complicated Option 7 microphysics will not increase the skill of the MM5 to forecast winter precipitation for Japan and Korea. The underlying conclusion of this research is that AFWA should not alter the cloud microphysics scheme currently employed to determine winter precipitation type for its East Asian forecast window.
Joint Poster Session 2, Severe Local Storms Forecasting (Joint with 21SLS and 19WAF/15NWP) new
Tuesday, 13 August 2002, 3:00 PM-4:30 PM
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