An overview of the Pentagon Shield 2004 field campaign

An overview will be presented of a highly focused meteorological field campaign that was conducted in April and May 2004 at the Pentagon in Washington, D.C. The goals of the campaign were 1) to characterize the perturbed wind, including turbulence, around the Pentagon and adjacent structures; 2) to measure the urban boundary layer's depth and thermodynamical profiles during day and night under various stability regimes; and 3) to trace the transport and diffusion of gases and aerosols around the Pentagon and within its complex architecture. A variety of instruments were used to meet these goals, including eye-safe lidars, portable weather stations, an instrumented tower, a sodar, radiosondes, a tethered blimp, and chemical-tracer sensors. The data from the field campaign are being used to compare the performances of the instruments used; to evaluate predictions from transport-and-diffusion models and from computational fluid dynamics models; to compare against results from wind-tunnel experiments; and to investigate general topics in urban micrometeorology as well as topics specific to the Pentagon itself.