Extended Abstract (1.5M)JP6.12
Microburst windspeed potential assessment: progress and developments
Kenneth L. Pryor, NOAA/NESDIS, Camp Springs, MD
A suite of products has been developed and evaluated to assess hazards presented by convective downbursts to aircraft in flight derived from the current generation of Geostationary Operational Environmental Satellite (GOES) (8-P). The existing suite of GOES microburst products employs the GOES sounder to calculate risk based on conceptual models of favorable environmental profiles for convective downburst generation. Large output values of the microburst index algorithms indicate that the ambient thermodynamic structure of the troposphere fits the prototypical environment for each respective microburst type (i.e. Wet, Hybrid, Dry, etc.). Accordingly, a diagnostic nowcasting product, the Microburst Windspeed Potential Index (MWPI), is designed to infer attributes of a favorable microburst environment: large CAPE and a convective mixed layer with a steep temperature lapse rate and low relative humidity in the surface layer. These conditions foster intense convective downdrafts due to evaporation of precipitation in the sub-cloud layer and the resultant generation of negative buoyancy. In addition, a GOES-West (GOES-11) imager microburst algorithm that employs brightness temperature differences between band 3 (upper level water vapor, 6.7μm), band 4 (longwave infrared window, 10.7μm), and split window band 5 (12μm) has been developed to supplement the sounder-derived products. This paper provides an updated assessment of the sounder MWPI and imager microburst algorithms, presents case studies demonstrating effective operational use of the microburst products, and presents validation results for the 2008 convective season over United States Great Plains and Great Basin regions. The MWPI algorithm is intended for implementation in the GOES-R Advanced Baseline Imager (ABI) that has promising capability as a sounder with greatly improved temporal and spatial resolution as compared to the existing GOES (8-P) sounders. The increase in temporal resolution should greatly aid the mesoscale forecaster in the analysis of trends in thermodynamic environments. Considering that seven of the sixteen bands of the ABI are in common with the bands of the heritage sounder, the ABI should effectively produce a sounding profile comparable in quality to the current GOES.
Supplementary URL: http://arxiv.org/abs/0810.1622
Joint Poster Session 6, Improvements to NWP and Short-term Forecasting
Wednesday, 14 January 2009, 2:30 PM-4:00 PM, Hall 5
Previous paper Next paper