Download Abstracts Here - IGAC Project

List of Abstracts 70of externally mixed dust, sea salt, sulfate, and carbonaceous aerosols. GEOS-5 is an integrated Earthsimulation modeling system that includes components for atmospheric and oceanic general circulation andphysics, atmospheric chemistry, oceanic biogeochemistry, land surface modeling, and data assimilation.With the GEOS-5/GOCART system, we have an atmospheric general circulation model (AGCM) in whichaerosol and trace gas species are dynamically and radiatively interactive with meteorology. Here we assessthe sensitivity of global and regional climates and the hydrologic cycle to the direct and semi-direct effectsof aerosols by considering a series of simulations in the GEOS-5/GOCART atmospheric general circulation(AGCM) model forced by observed sea surface temperatures. In the control simulation, there is no radiativeforcing by aerosols. In another simulation, we have direct and semi-direct forcing from prescribed aerosolsonly (i.e. aerosol distributions are decoupled from AGCM meteorology). In the final simulation aerosolspecies are dynamically and radiatively interactive with model meteorology. Each simulation’s aerosoldistributions are evaluated for their representativeness with comparisons to observations from satellite(MODIS, MISR) and in-situ observations (AERONET). The response of each simulation to aerosol forcingis examined in comparison to the control simulation.P-Chemistry Climate.23 ID:4527 15:35Investigating the climate response to the direct and indirect effects of anthropogenic aerosols overSouth-Asia using an improved version of the coupled atmosphere-mixed layer ocean model SM2.1Dilip Ganguly, V Ramaswamy, Paul Ginoux, Yi MingGeophysical Fluid Dynamics Laboratory, Princeton, NJ, USAContact: dilip.ganguly@noaa.govFor almost two decades now, aerosols from South Asia has attracted the attention of researchers all acrossthe globe. Investigating the climate response to the direct and indirect effects of anthropogenic aerosolsemitted from this region is essential to understand and predict climate change not just in Asia but alsoglobally. This study investigates the equilibrium climate response to the direct and indirect effects of thepresent day anthropogenic and biomass burning aerosols over South-Asia and monsoon dynamics using animproved version of the coupled atmosphere-mixed layer ocean model SM2.1. Our control experimentincludes emission of aerosols from only natural sources such as wind blown dust, sea salt, organics fromvegetation, and volcanic aerosols. The successive perturbation experiments include emissions of aerosolsfrom present-day biomass burning and anthropogenic sources (based on IPCC AR5 emission estimates forthe year 2000) in addition to the naturally produced aerosols. In all our experiments, we used the 1860 (preindustrial)forcing data for long-lived green house gases, ozone and land surface properties. The simulationsfor control and all perturbation experiments have been carried out for 100 model years, and the averageresults from the last 40 years have been used for further analysis. Anomalies in simulated parameters likeprecipitation, temperature, atmospheric heating rate, vertical wind velocity, surface pressure, liquid cloudamount, ice cloud amount, SW TOA clear and cloudy sky fluxes etc. between the perturbed cases and thecontrol run will be examined to understand the impact of anthropogenic and biomass burning aerosols on theclimate over South-Asia and monsoon dynamics. Our results show that the anthropogenic aerosols oversouth Asia cools the atmosphere over land and northern Indian ocean, stabilizes the atmosphere over landand weakens the monsoon circulation.P-Chemistry Climate.24 ID:4557 15:35Concentration of Nano-particles and Gases in the Environment of Gaborone, BotswanaShibu John, Tej Verma, Tessy Thomas1 University of Botswana2 University of BotswaaniCACGP-IGAC 2010 12 July, 2010