Hydroclimate of the Americas: Land Surface Effects on the Overlying Atmosphere
An important motivation for the study of land-atmosphere interactions is to improve weather and climate predictability. The land is a source of atmospheric persistence by storing water in the soil where the time scales of variability are much longer than in the atmosphere. We can leverage this persistence for improved predictability of variables like temperature and precipitation. In this talk I will focus on three physical processes through which the land affects the atmosphere: 1) evapotranspiration (latent heat) 2) sensible heat and 3) surface roughness. I will give examples of our studies of regional hydroclimate processes in North America and South America.
Land surface evapotranspiration is an important source of moisture in regions such as the North American Monsoon, the Great Plains of the United States, the Amazon river basin and the La Plata river basin in South America. I will provide an overview of our work quantifying the sources of moisture for these different regions, and the tools that we use in our analyses. Changes in soil moisture – particularly dry soil moisture anomalies - can also affect the overlying atmosphere by changing sensible heat fluxes, surface temperature, and large-scale surface pressure. Over South America this mechanism can modify the path of the South American low-level jet and profoundly impact the location and intensity of precipitation. South America is also a region where the land surface is being dramatically transformed for human consumption. Large regions of Amazon forest and the plains of La Plata basin have been transformed into crops. I will discuss how anthropogenic changes in the land surface can impact the hydroclimate of the continent.
Dr. Francina Dominguez is an associate professor in the Department of Atmospheric Sciences at the University of Illinois. As a hydroclimatologist, her work is focused on the interactions between the land and the atmosphere, and more specifically, on changes in hydrology and climate due to human modification of the land surface and greenhouse gas emissions. The two primary lines of research in her group look at land-atmosphere interaction from two perspectives: 1) the effect of climate variability and change, primarily extreme events, on surface hydrology and 2) the effect of changes in surface hydrology on climate.