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Soil moisture in the climate system: why it matters

Speaker: Alexis Berg, Princeton University
Series: EEWR Brown Bag Seminars
Location: Engineering Quad E225
Date/Time: Friday, February 15, 2019, 12:00:00 p.m. - 01:00:00 p.m.


Alexis BergFar from being simply a passive boundary condition to the atmosphere, the land surface continuously interacts with it. Indeed, changes in land surface conditions such as soil moisture, while driven in part by atmospheric  variability and change, can also feedback onto the atmosphere by altering land-atmosphere water and energy fluxes. Thus, the land surface may strongly control over the mean climate over land and influence its variability and change.

In this talk I will present results that demonstrate the widespread implications of land-atmosphere processes for the behavior of land hydroclimate, focusing in particular on the role of soil moisture-atmosphere coupling. Through the use of climate model experiments, I will show how feedback pathways tied to soil moisture shape surface hydroclimate locally and atmospheric circulation regionally. Furthermore, I will highlight how projected changes in soil moisture  under greenhouse warming, as well as changes in vegetation properties, modulate key large-scale aspects of climate change, such as land-ocean contrasts in warming and humidity changes. The latter results are critical to our interpretation of projected future changes in the continental water cycle, in particular future droughts and aridity: central to this issue is the understanding of projected evaporative demand trends over land in the context of the coupled land-atmosphere system.

These results underscore the critical importance of soil moisture processes in the climate system, and highlight the need to accurately represent land-atmosphere processes in climate models to reduce associated model uncertainties and better predict future climate.