Seasonal and Diurnal Cycles of Surface Energy Partitioning in Subirrigated meadow, Dry Valley, and Upland Dune Ecosystems During 2004 in the Semi-Arid Sand Hills of Nebraska, USA
Abstract
Evapotranspiration (ET) impacts local and regional hydrologic organization on various spatial and temporal scales. Due to the importance of the Ogallala (High Plains) Aquifer, accurate estimation of ET in the Great Plains is vital for efficient water resource management. One of the areas with the largest saturated thickness in this region (the Sand Hills) is the unique grass-stabilized eolian (windblown) sand dunes covering roughly 50,000 - 60,000 km2 of Nebraska. Our study site is located near Whitman, Nebraska which is located in the heart of the Sand Hills region. There, a system of five major land cover types prevail: (1) lakes, (2) wetlands (with lakes, ~5%), (3) subirrigated meadows (water table is within ~1 m of surface; ~10%), (4) dry valleys (water table is 1-10 m below surface; ~20%), and (5) upland dunes (water table is more than 10 m below surface; ~65%). By better understanding seasonal and diurnal properties of hydrologic organization among these different ecosystems, regional water resource assessment will be improved. The surface energy and water balances were analyzed using Bowen ratio energy balance systems (BREBS) observations at three locations during 2004: (1) a subirrigated meadow, (2) a dry valley, and (3) an upland dune. Results reveal a strong spatial gradient between sites in latent and sensible heat, diurnally and seasonally, that is likely associated with undulating topographic relief containing depressions which support different vegetative communities that ultimately influence energy partitioning differently at each site.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H33A1278H
- Keywords:
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- 1814 HYDROLOGY / Energy budgets;
- 1818 HYDROLOGY / Evapotranspiration;
- 1833 HYDROLOGY / Hydroclimatology;
- 1855 HYDROLOGY / Remote sensing