SURF: understanding and predicting urban convection and haze

Urbanization modifies atmospheric energy and moisture balances, forming distinct features, e.g., urban heat islands (UHIs) and enhanced or decreased precipitation. These produce significant challenges to science and society, including rapid and intense flooding, heat waves strengthened by UHIs, and air pollutant haze. The Study of Urban-Impacts on Rainfall and Fog/Haze (SURF) has brought together international expertise on observations and modeling, meteorology and atmospheric chemistry, and research and operational forecasting. The SURF overall science objective is a better understanding of urban, terrain, convection, and aerosol interactions for improved forecast accuracy. Specific objectives include: a) promoting cooperative international research to improve understanding of urban summer convective precipitation and winter particulate episodes via extensive field studies; b) improving high-resolution urban weather and air quality forecast-models; and c) enhancing urban weather forecasts for societal applications, e.g., health, energy, hydrologic, climate change, air quality, planning, and emergency-response management. Preliminary SURF observational and modeling results are shown, i.e., turbulent PBL structure, bifurcating thunderstorms, haze events, urban canopy model development, and model forecast evaluatio

Western Pacific international meeting and workshop on Toga Coare : proceedings

An important atmospheric goal of TOGA COARE is to determine the exchange of momentum, and sensible and latent heat in the western Pacific over the time scales of convective storms, westerly bursts and lower frequency events. TOGA COARE will also require detailed moisture budget studies in support of improved undestanding of sub-gridscale processes and the evaluation of model parameterization schemes systems do not provide observations on the temporal and spatial scales necessary to properly address these and other issues. We present the concept of the so-called Boundary-Layer Integrated Sounding System (BLISS) as a means to provide these measurements. The BLISS consists of a suite of demonstrated in situ and remote sensing subsystems which together provide the measurements. The BLISS consists of a suite of demonstrated in situ and remote sensing subsystems which together provide the measurements to sense directly or retrieve high-resolution profiles of winds, temperature and moisture and associated fluxes

Measurements of NOx emissions from the Antarctic snowpack

It has been shown that NOx is produced photochemically within the snowpack of polar regions. If emitted to the atmosphere, this process could be a major source of NOx in remote snowcovered regions. We report here on measurements made at the German Antarctic station, Neumayer, during austral summer 1999, aimed at detecting and quantifying emissions of NOx from the surface snow. Gradients of NOx were measured, and fluxes calculated using local meteorology measurements. On the 2 days of flux measurements, the derived fluxes showed continual release from the snow surface, varying between similar to0 and 3x10(8) molecs/cm(2)/s. When not subject to turbulence, the variation was coincident with the uv diurnal cycle, suggesting rapid release once photochemically produced. Scaling the diurnal average of Feb. 7th (1.3x10(8) molecs/cm(2)/s) suggests an annual emission over Antarctica of the order 0.0076TgN