Joint Seminar: Separating the impact of individual land surface properties on both the coupled and un-coupled land-atmosphere system

Changes in vegetation modify many different properties of the land surface simultaneously, and these changes in the land surface modify energy fluxes in ways that can significantly impact surface climate. Surface properties modified by vegetation include the land albedo, through changes in leaf colour and leaf area, the aerodynamic roughness of the land surface, through changes in vegetation height, and the evaporative resistance of the surface, through changes in stomatal resistance and rooting depth. Often, the atmosphere responds in interesting ways to modelled vegetation change, but it can be unclear what exactly about the vegetation change it is responding to. Here, I untangle the impact of individual surface properties using an idealized land model coupled to a complex Earth system model.

 

Additionally, the impact of changing surface properties on surface climate can be separated into the direct effect of surface properties on the surface energy budget, and the effect on the surface due to atmospheric feedbacks to that land surface change. For example, with all else held equal, a dark surface would absorb more solar energy than a bright surface, thus may be warmer than the bright surface – this is the direct effect. However, a change in surface fluxes in response to reduced surface albedo could also impact the atmosphere by modifying atmospheric temperatures, moisture, and cloud cover, in ways that feedback on the surface energy budget. I will quantify the magnitude of these atmospheric feedbacks to idealized, global-scale changes in individual land surface properties.

Date

27.03.2019

Time

13:30 h

Place

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

Speaker

Marysa Laguë, University of Washington

Chair

Cathy Hohenegger

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