Meteorological characteristics important in emergency response

Approximately half of the world's population currently lives in cities, and there is a growing necessity for major urban centers to consider the threat of harmful atmospheric releases. However, the highly complex air flows through and around cities are not fully understood. Over the past several years, a number of urban field campaigns have been conducted to measure and advance our understanding of complex wind interactions from the scale of synoptic meteorology to urban canyon winds.

This talk will discuss some of the characteristics of meteorology that are especially important for urban emergency response with an emphasis on observations made during the Midtown Manhattan 2005 (MID05) experiment which was conducted as part of the U.S. Department of Homeland Security Urban Dispersion Program. National Weather Service stations located outside cities may not always provide the best measure of the winds for an emergency response in a city. Measurements made during MID05 reveal that building-top meteorological stations in cities can enhance the tools available to urban emergency responders. An additional asset for urban response is remote sensing profile measurements as obtained by sodars or radars. These provide wind speed and direction up to several hundreds or thousands of meters above the surface. The importance of understanding how synoptic conditions can affect an urban center and the value of building-top and profile measures is illustrated with a brief analysis of the January 8, 2007 stagnation event in which a gas-like odor permeated throughout the New Jersey-New York City metropolitan area.

(PNNL-SA-55607)