Submitted to: American Association for Aerosol Research
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2005
Publication Date: 10/17/2005
Citation: Niyogi, D., Chang, H., Booker, F.L., Pielke, R., Matsui, T., Gu, L., Saxena, V., Wells, R., Xue, Y. 2005. Outstanding issues regarding the role of atmospheric aerosols on terrestrial biosphere and regional climate. Proceedings 24th Annual Meeting of the American Association for Aerosol Research, Austin, TX. pg. 116. Interpretive Summary:
Technical Abstract: Atmospheric aerosols have a complex feedback on the earth’s climate. Past studies related to studying the impact of aerosols on the earth’s climate had focused on upper atmospheric processes including cloud-aerosol- radiative interactions. Recent evidence from field and model studies indicates that aerosols could also have a significant feedback on the earth’s climate by affecting the land surface. Changes in the land atmosphere interactions can further impact the regional climate by redistributing radiative energy, and impacting the regional hydrological and biogeochemical response. Using a combination of satellite, surface data, field experimentation, and numerical model results, we will present a synthesis of the aerosol’s land surface interactions in a scale down mode, i.e., impacts seen at continental to global scales, to regional scale, and at the plot scales. The focus will be on carbon and water vapor fluxes, and the integrated feedback on the regional environment. We will conclude that the aerosol effects and the effects due to global dimming are still uncertain, and the confounding caused by the various interactions becomes a dominant feedback when assess the impacts. The confounding and resulting interactions appear to increase at smaller scales (i.e. highest uncertainty is at individual field scales, and more certainty at regional to continental scales). Results indicate there is a potential for increased regional productivity through a more vigorous carbon / biogechemical cycle, and a potential for a uncertain water cycle feedback with reduction in evaporation and increased transpiration but an overall reduction in water vapor loss due to increased surface albedo. The translation of these potential impacts on the feedback of aerosols on the regional productivity and water cycle will depend on the atmospheric interactions.