92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Monday, 23 January 2012: 11:30 AM
Application of Flash Rate Parameterization Schemes and Resulting Lightning NOx Production in Cloud-Resolved WRF Forecasts
Room 342 (New Orleans Convention Center )
Kristin A. Cummings, University of Maryland, College Park, MD; and K. E. Pickering, M. C. Barth, and M. Weisman

Test flights for the Deep Convective Clouds and Chemistry (DC3) field campaign took place between 2 and 15 May 2011 over the Central Plains. The NCAR WRF ARW model provided guidance for forecasters in determining when and where flights should occur based on simulated radar reflectivity and chemical tracer products. A component of the WRF forecasts included the application of several flash rate parameterization schemes tested by Barthe et al. (2010) in mid-latitude convective events. Three flash rate prediction schemes were tested during the DC3 test flights: those using maximum vertical velocity, updraft volume and cloud top height as predictor variables. For verification, the predicted flash rates from each scheme were compared against NLDN observations. Lightning-generated NOx (LNOx) was also calculated based on the lightning flash rates predicted by each scheme, where NO is distributed vertically following Gaussian distributions of intracloud and cloud-to-ground flashes and horizontally within the 20 dBz contour. Additionally, the resulting LNOx based on the maximum vertical velocity predictor was advected in the model as a tracer with lifetimes specified as a function of altitude. The same three flash prediction schemes plus three additional schemes (those using precipitation ice mass, ice water path, precipitation and non-precipitation ice mass flux product as predictor variables) were run for several convective events which occurred during 10-11 June 2010. The analysis of performance of the flash rate parameterization schemes during the 2011 DC3 test flights and the June 2010 case study provide insight into which schemes should be used and how they should be adjusted for future use during forecasting for the DC3 field campaign in May-June 2012.

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