Monday, 12 January 2009
Radar Refractivity Retrievals from KTLX: Benefits and Limitations to Operational Forecasting
Hall 5 (Phoenix Convention Center)
The KTLX Spring 2007 and 2008 Refractivity Experiments were designed to investigate the potential utility of high-resolution, near-surface refractivity measurements to operational forecasting. During the experiments, forecasters at the Norman, Oklahoma National Weather Service Forecast Office assessed refractivity and scan-to-scan refractivity difference products retrieved from the Weather Surveillance Radar-1988 Doppler weather radar near Oklahoma City (KTLX). In both 2007 and 2008, forecasters completed a survey designed to measure the impact of refractivity products on forecast operations. Analysis of the 27 surveys completed in 2007 revealed that refractivity products were most useful to forecasters for evaluating changes in the low-altitude temperature and moisture undetectable in the Oklahoma Mesonet or KTLX reflectivity data.
Confidence ratings depended on the correspondence of refractivity products to familiar operational data sets like the Oklahoma Mesonet, KTLX reflectivity factor, and visible satellite. Forecasters preferred the refractivity product when the near-surface environment was fairly homogeneous, and preferred scan-to-scan refractivity difference when moisture gradients were present. Traditional techniques for identifying boundaries outperformed refractivity techniques when horizontal moisture and/or temperature gradients were weak. Findings from the 2008 Refractivity Experiment will be included in the extended abstract.