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MODELED MESOSCALE METEOROLOGICAL FIELDS WITH FOUR-DIMENSIONAL DATA ASSIMILATION IN REGIONAL SCALE AIR QUALITY MODELS
Citation:
Ching, J.K.S. AND J. Irwin. MODELED MESOSCALE METEOROLOGICAL FIELDS WITH FOUR-DIMENSIONAL DATA ASSIMILATION IN REGIONAL SCALE AIR QUALITY MODELS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-93/046 (NTIS PB93167229), 1993.
Description:
This paper addresses the need to increase the temporal and spatial resolution of meteorological data currently used in air quality simulation models, AQSMs. ransport and diffusion parameters including mixing heights and stability used in regulatory air quality dispersion models are currently computed using routinely collected twice daily (00Z and 12Z) upper air sounding data from approximately 100 locations, and hourly surface data from approximately 300 locations spread across the US. his limited resolution data base limits the accuracy, reliability and validity of the derived dispersion parameters for air quality models. The MM4-FDDA (Mesoscale Meteorological Model, Version 4 with Four Dimensional Data Assimilation), a state-of-science dynamic modeling system that assimilates routinely available surface and upper air sounding data has been demonstrated to provide accurate and well characterized primary meteorological fields on hourly time intervals, with fine horizontal and vertical resolution. he MM4-FDDA can also provide as outputs, parameters such as surface heat and momentum fluxes which are necessary for computing the stability dispersion parameters. he goal of this study is to generate meteorological date with accuracy of transport, precipitation and dynamic consistency superior to both direct interpolation of synoptic scale analyses of observation and on-site meteorology, and purely predictive mode model results. his is a demonstration project to produce a one year meteorological data base on an hourly basis for a horizontal grid resolution of 80 km and for 15 vertical layers is underway. he output is formatted as though the 5jmulated fields were "observations", in order to facilitate incorporation into AQSMs. he data base is thus increased by more than two orders of magnitude (12 X in time, 20-30X in the horizontal). erived quantities including surface heat and momentum fluxes, mixing heights, cloud cover, radiation are also provided as an option.
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MODELED MESOSCALE METEOROLOGICAL FIELDS WITH FOUR-DIMENSIONAL DATA ASSIMILATION IN REGIONAL SCALE AIR QUALITY MODELS