Monday, January 28, 2013, 12:00PM - 1:00PM
Abstract: Assessment of potential climate change impacts on seasonal water and energy budgets over the central and southern Rocky Mountains is challenged by the presence of highly complex orography and variability in land surface hydrologic conditions. Here we explore the hypothesis that large magnitude topographic gradients expressed over small distances necessitate the need for high resolution models in order to properly simulate the dynamics of cold and warm season precipitation events and their runoff responses.
Results from high-resolution (4km) regional climate model time-slice experiments over the central and southern Rocky Mountains are presented in the context of understanding the how well we presently modelland surface water budgets. Water budget analyses from the high resolution model are contrasted with those from coarser resolution regional model simulations and from the parent global model from which a component of the regional model forcing was derived. Water budget partitioning is shown to be highly sensitive to model resolution and exhibits differential changes between different seasons. The reasons for these sensitivities relate to biases in precipitation processes in the different resolutions of the model. Modeled precipitation and seasonal runoff values are also mapped according to headwater river basins ranging in spatial scale from a few hundred km2 to 10,000's of km2 and are evaluated against available observations as a means to assess model credibility. Finally, results from a constrained climate warming experiment using the multi-resolution model results are also presented.
It is shown that not only does the regional model produce different magnitudes of change in current and future water budgets than the global model but that there are distinct changes in the seasonality and, at times, the sign of the annual changes. The results of the river basin scale analyses show periods of significant potential for future water resource stress in seasonal water budget change patterns produced by the regional model.
Bio: Dr. Gochis joined NCAR as a post-doctoral fellow in 2002 and moved to NCAR's scientific staff in 2004. His academic background is interdisciplinary between the meteorological and hydrological sciences and civil and agricultural engineering disciplines, having earned degrees in both Atmospheric Sciences and Hydrology and Water Resources. Prior to returning to academia Dr. Gochis worked as a consulting engineer for CH2MHill in Portland, Oregon where he conducted water resources evaluations and designed irrigation systems.
His current research interests include hydrometeorology, hydroclimatology, atmospheric convection and land surface hydrology. His main research foci have been on observation, diagnosis and modeling of precipitation and runoff processes in complex terrain with specific emphasis on the North American Monsoon system. He has led and collaborated in several domestic and international field campaigns. Dr. Gochis's research develops and employs weather, climate, and hydrological models to improve understanding and prediction of regional hydrometeorological and hydroclimatological processes.
Free and open to the public