Verification of a Mesoscale Data-Assimilation and Forecasting System for the Oklahoma City Area during the Joint Urban 2003 Field ProjectSource: Journal of Applied Meteorology and Climatology:;2006:;volume( 045 ):;issue: 007::page 912DOI: 10.1175/JAM2383.1Publisher: American Meteorological Society
Abstract: The National Center for Atmospheric Research (NCAR) and the U.S. Army Test and Evaluation Command have developed a multiscale, rapid-cycling, real-time, four-dimensional data-assimilation and forecasting system that has been in operational use at five Army test ranges since 2001. This system was employed to provide operational modeling support for the Joint Urban 2003 (JU2003) Dispersion Experiment, conducted in Oklahoma City, Oklahoma, during July 2003. To better support this mission, modifications were made to the nonlocal boundary layer (BL) parameterization (known as the Medium Range Forecast scheme) of the fifth-generation Pennsylvania State University?NCAR Mesoscale Model, in order to improve BL forecasts. The NCEP?Oregon State University?Air Force?Hydrologic Research Laboratory land surface model was also improved to better represent urban forcing. Verification of the operational model runs and retrospectively simulated cases show 1) a significantly reduced low bias in the forecast surface wind speed and 2) more realistic daytime BL heights. During JU2003, the forecast urban heat island, urban dry bubble, and urban BL height agree reasonably well with observations and conceptual models. An analysis of three-dimensional atmospheric structures, based on model analyses for eight clear-sky days during the field program, reveals some interesting features of the Oklahoma City urban BL, including complex thermally induced circulations and associated convergence/divergence zones, a nocturnal thermal shadow downwind of the urban area, and the reduction of low-level jet wind speeds by more vigorous nocturnal mixing over the city.
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contributor author | Liu, Yubao | |
contributor author | Chen, Fei | |
contributor author | Warner, Thomas | |
contributor author | Basara, Jeffrey | |
date accessioned | 2017-06-09T16:47:56Z | |
date available | 2017-06-09T16:47:56Z | |
date copyright | 2006/07/01 | |
date issued | 2006 | |
identifier issn | 1558-8424 | |
identifier other | ams-74316.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4216528 | |
description abstract | The National Center for Atmospheric Research (NCAR) and the U.S. Army Test and Evaluation Command have developed a multiscale, rapid-cycling, real-time, four-dimensional data-assimilation and forecasting system that has been in operational use at five Army test ranges since 2001. This system was employed to provide operational modeling support for the Joint Urban 2003 (JU2003) Dispersion Experiment, conducted in Oklahoma City, Oklahoma, during July 2003. To better support this mission, modifications were made to the nonlocal boundary layer (BL) parameterization (known as the Medium Range Forecast scheme) of the fifth-generation Pennsylvania State University?NCAR Mesoscale Model, in order to improve BL forecasts. The NCEP?Oregon State University?Air Force?Hydrologic Research Laboratory land surface model was also improved to better represent urban forcing. Verification of the operational model runs and retrospectively simulated cases show 1) a significantly reduced low bias in the forecast surface wind speed and 2) more realistic daytime BL heights. During JU2003, the forecast urban heat island, urban dry bubble, and urban BL height agree reasonably well with observations and conceptual models. An analysis of three-dimensional atmospheric structures, based on model analyses for eight clear-sky days during the field program, reveals some interesting features of the Oklahoma City urban BL, including complex thermally induced circulations and associated convergence/divergence zones, a nocturnal thermal shadow downwind of the urban area, and the reduction of low-level jet wind speeds by more vigorous nocturnal mixing over the city. | |
publisher | American Meteorological Society | |
title | Verification of a Mesoscale Data-Assimilation and Forecasting System for the Oklahoma City Area during the Joint Urban 2003 Field Project | |
type | Journal Paper | |
journal volume | 45 | |
journal issue | 7 | |
journal title | Journal of Applied Meteorology and Climatology | |
identifier doi | 10.1175/JAM2383.1 | |
journal fristpage | 912 | |
journal lastpage | 929 | |
tree | Journal of Applied Meteorology and Climatology:;2006:;volume( 045 ):;issue: 007 | |
contenttype | Fulltext |