CGA Student Speaker Series
Aleya Kaushik "Investigating climate in the atmospheric surface layer using stable water isotopes"
The moisture balance of the continental boundary layer plays an important role in regulating the exchange of water and energy between the land surface and atmosphere. The surface layer moisture balance is controlled by a number of factors including precipitation, infiltration, evaporation and transpiration. Measurements of stable isotope ratios in water can be exploited to better understand the mechanisms controlling atmosphere-land surface water fluxes. This talk will focus on the use of stable water isotopes as a tool to study climate and variability in the water cycle in the Front Range. I will present three years of in situ tower-based measurements of stable isotope ratios of water (δD and δ18O) in vapor, precipitation, vegetation and soil from the Boulder Atmospheric Observatory, a semi-arid 300 meter tall-tower site in Erie, Colorado. Co-located meteorological and disdrometer measurements at the surface and 300m allow us to explore key aspects of continental moisture cycling in a semi-arid environment such as the important contribution of sub-surface vapor diffusion to the surface water vapor budget and its implications for partitioning in dry ecosystems, and the role of rain evaporation during precipitation events on inter-event and seasonal time scales.
Lunch will be provided.
Cryospheric and Polar Processes Seminar: Drew Slater
Will the Terrestrial Arctic turn to Mush?
By Dr. Drew Slater - NSIDC/CIRES, University of Colorado Boulder
Projections regarding the future of permafrost in the terrestrial Arctic have been many and varied, with some debate having occurred in the literature. How can we interpret various results, what can we learn about our models and how does that inform us about future directions? These matters will be investigated using results from the CMIP5 models (as used in the IPCC reports) and provide us with insights regarding model and data needs.