Terrestrial Water Cycle Seminar (formerly LIS Science)

Code 614.3/Hydrological Sciences Branch
Matthew Czikowsky Atmospheric Sciences Research Center SUNY-Albany Observing spatial and seasonal changes in watershed response to rainfall events The hydrologic response of watersheds to transient precipitation events may be expected to change as a result of spatial and temporal variations in the forcings these watersheds receive. Examples of such forcing variations include: a) spatial differences in upland watershed precipitation due to orographic effects; b) seasonal changes in watershed evapotranspiration resulting from growing-to-dormant season transition; c) changes in watershed evapotranspiration and soil hydraulic properties due to land-cover land-use change. Seasonal and spatial variation in watershed response to rainfall is analyzed observationally using streamflow and soil moisture data, combined with the BROOK hydrological model (Federer 1995) in three stages: a) the period when streamflow or soil moisture peaks following input precipitation; b) the streamflow or soil moisture recession following the peak; c) the evapotranspiration-driven diurnal streamflow fluctuations that may occur during the dry periods between rainfall events once the streamflow has receded to its baseflow. Studies are conducted in two regions with contrasting climates. The first location is a network of watersheds located in Catskill-Hudson Valley region of New York State. In this region, precipitation patterns are strongly influenced by topography, and evapotranspiration forcing changes as leaf state changes seasonally. The second location includes a small group of watersheds located in the Amazon region of Brazil. In this region of the equatorial tropics, precipitation is seasonal, with distinct wet and dry seasons. Evapotranspiration and soil properties change in response to land cover changes, primarily the result of deforestation.