Plans for the Madison Square Garden 2004 (MSG04) tracer experiment in Manhattan

In Manhattan, the buildings are much taller and the downtown urban area is much larger than in Salt Lake City or Oklahoma City, where recent urban tracer experiments took place. As part of the Urban Atmospheric Observatory (UAO) project, a tracer experiment (MSG-04) is planned for the Madison Square Garden area of Manhattan in Fall of 2004. The focus will be on vertical transport and dispersion concerns in deep urban street canyons and adjacent to very tall buildings (height > 200 m). Six different PFT tracer gases will be released from five locations around MSG and simultaneously sampled at 30 locations at distances 400 m or less from MSG. Vertical profiles will be sampled on the windward and lee sides of the 250 m tall One Penn Plaza building. Numerous sonic anemometers will be installed at street level and up the sides of the building. The resulting data will be analyzed in order to develop and test improved flow and dispersion models for very large urban areas, and to better plan a more extensive tracer experiment in 2005. The UAO/MSG-04 experiment goals and plans are discussed in this paper.