Seminar – Dr Dennis Lettenmaier: Wednesday 23rd March at 10:30am

Dr Dennis Lettenmaier of the University of Washington will speak on the topic of ‘Unanswered questions in predicting the hydrologic impacts of climate change’, on Wednesday, March 23, 2011, from 10:30 to 11:30 am, in the Convocation Hall.
Here is an abstract of Dr Lettenmaier’s presentation:
From a societal perspective, changes in the land surface water cycle, perhaps aside from sea level rise, represent the most pervasive impacts of climate change. It is well established that increases in concentrations of greenhouse gases, most notably CO2 and CH4, will lead to increases in surface temperatures globally, and these effects are now evidenced in global observations. Furthermore, from first principles, increases in air temperature lead to higher atmospheric moisture, and in turn precipitation. Unfortunately, the implications of these global changes are much more difficult to unravel on a regional level, a problem that is compounded, from the standpoint of land surface hydrology, by the low skill of current generation climate models in representing precipitation. However, even absent these uncertainties, there remain key issues in our ability to represent land surface hydrologic sensitivities to a changing climate. Dr Lettenmaier will discuss three of these areas of uncertainty:
– In hydrologic model predictions of the precipitation and temperature sensitivities of annual runoff
– In the sensitivity of floods to changes in precipitation
– In the coupled interaction of atmospheric circulation and river runoff