The ATEC 4DWX system was adapted for use over metropolitan areas, and this capability was tested during the Joint Urban 2003 urban field study in Oklahoma City in July. A version of the GlobalMOD system with five nested grids employed the highest-resolution grid that spanned the limits of the city, with a horizontal resolution of 500 m. The Urban Wind Module (UWM) from the Defense Threat Reduction Agency (DTRA) was embedded in this inner grid. The UWM winds were used as input to the DOD SCIPUFF transport and dispersion model.

RTFDDA modeling study of OKC UHI

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. Figure on right show the mean 2-m temperature and 10-m winds of RTFDDA model output on eight clear-sky days. OKC urban regions are marked with think solid lines.