Affiliation:
1. School of Meteorology, University of Oklahoma, Norman, Oklahoma
2. NOAA/OAR/National Severe Storms Laboratory, Norman, Oklahoma
3. NOAA/NWS/Storm Prediction Center, Norman, Oklahoma
4. School of Meteorology, and Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma
5. Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma
Abstract
Abstract
During the 2007 NOAA Hazardous Weather Testbed (HWT) Spring Experiment, the Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma produced convection-allowing forecasts from a single deterministic 2-km model and a 10-member 4-km-resolution ensemble. In this study, the 2-km deterministic output was compared with forecasts from the 4-km ensemble control member. Other than the difference in horizontal resolution, the two sets of forecasts featured identical Advanced Research Weather Research and Forecasting model (ARW-WRF) configurations, including vertical resolution, forecast domain, initial and lateral boundary conditions, and physical parameterizations. Therefore, forecast disparities were attributed solely to differences in horizontal grid spacing. This study is a follow-up to similar work that was based on results from the 2005 Spring Experiment. Unlike the 2005 experiment, however, model configurations were more rigorously controlled in the present study, providing a more robust dataset and a cleaner isolation of the dependence on horizontal resolution. Additionally, in this study, the 2- and 4-km outputs were compared with 12-km forecasts from the North American Mesoscale (NAM) model. Model forecasts were analyzed using objective verification of mean hourly precipitation and visual comparison of individual events, primarily during the 21- to 33-h forecast period to examine the utility of the models as next-day guidance. On average, both the 2- and 4-km model forecasts showed substantial improvement over the 12-km NAM. However, although the 2-km forecasts produced more-detailed structures on the smallest resolvable scales, the patterns of convective initiation, evolution, and organization were remarkably similar to the 4-km output. Moreover, on average, metrics such as equitable threat score, frequency bias, and fractions skill score revealed no statistical improvement of the 2-km forecasts compared to the 4-km forecasts. These results, based on the 2007 dataset, corroborate previous findings, suggesting that decreasing horizontal grid spacing from 4 to 2 km provides little added value as next-day guidance for severe convective storm and heavy rain forecasters in the United States.
Publisher
American Meteorological Society
Reference55 articles.
1. The sensitivity of numerically simulated cyclic mesocyclogenesis to variations in model physical and computational parameters.;Adlerman;Mon. Wea. Rev.,2002
2. Sensitivity of several performance measures to displacement error, bias, and event frequency.;Baldwin;Wea. Forecasting,2006
3. A new convective adjustment scheme. Part I: Observational and theoretical basis.;Betts;Quart. J. Roy. Meteor. Soc.,1986
4. A new convective adjustment scheme. Part II: Single column tests using GATE wave, BOMEX, and arctic air-mass data sets.;Betts;Quart. J. Roy. Meteor. Soc.,1986
5. The new NMC mesoscale Eta Model: Description and forecast examples.;Black;Wea. Forecasting,1994
Cited by
198 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献