HR: 08:30h
AN: H31I-03    [Abstracts]
TI: TES: An Unexpected Opportunity to Revolutionize Large Scale Hydrological Studies
AU: * Fekete, B M
EM: balazs.fekete@unh.edu
AF: University of New Hampshire, Complex Systems Research Center, Durham, NH 03824, United States
AU: Noone, D C
EM: dcn@Colorado.EDU
AF: University of Colorado, Dept Atmospheric & Oceanic Sc, Boulder, CO 80309, United States
AU: Wollheim, W M
EM: wil.wollheim@unh.edu
AF: University of New Hampshire, Complex Systems Research Center, Durham, NH 03824, United States
AU: Vorosmarty, C J
EM: charles.vorosmarty@unh.edu
AF: University of New Hampshire, Complex Systems Research Center, Durham, NH 03824, United States
AB: Stable isotopes of hydrogen and oxygen have proven to be useful tracers in catchment scale hydrology. Water molecules involving heavier isotopes of hydrogen (deuterium) or oxygen (oxygen-18) tend to stay in lower phase (solid or liquid) during phase changes resulting in a unique labeling effect. The labeled water fluxes often go through further transformation via mixing in the various storage pools of the water cycle. The resulting isotope signals are useful indicators of the hydrological processes affecting the water circulation in the hydrological cycle. Isotopes often offer a different viewing angle to the hydrological processes providing much needed independent validation information. The application of stable isotopes is largely limited today to catchment scale hydrological studies due to the difficulties in carrying out the intensive "in-situ" isotope sampling campaigns in large watersheds. The adequate sampling of the precipitation is particularly critical for the successful applications. The International Atomic Energy Agency recognized the importance of the stable isotope applications in large scale hydrological studies and initiated two programs to gather isotope information about the precipitation (Global Network of Isotopes in Precipitation, GNIP) and river runoff (Global Network of Isotopes in Rivers). While these efforts opened the door to large scale stable isotopes studies, the operational use of stable isotopes is still limited by the availability of time varying isotope information. The Water Systems Analysis Group of University of New Hampshire pioneered application of stable isotopes in large scales by developing isotope enabled version of its Water Balance/Transport model suite (WBM/WTM) in collaboration with the Isotope Hydrology Section of the International Atomic Energy Agency. While this effort demonstrated the potential of isotope hydrology in large watersheds, the lack of isotope data beyond what GNIP and GNIR has to offer limits the extension of the stable isotope applications. Recent discovery of the Tropospheric Emission Spectrometer's ability to detect the deuterium composition of the atmospheric water vapor and the potential of estimating the deuterium distribution in the boundary layer (aka precipitation) is opening new opportunities for the wider application of isotope hydrology. The ability to estimate the stable isotope composition of the precipitation removes the biggest obstacle to wide adaptation of isotope hydrology. While the adequate "in-situ" monitoring of precipitation is a costly endeavor, the complementary sampling of integrated isotope signals in major rivers is much more feasible. Our presentation will demonstrate the significance of stable isotopes in large scale hydrological studies. We will discuss the key processes and the resulting hydrological signals at continental scale applications. The presentation will layout the expected opportunities in applying isotope hydrology to answer unresolved science questions like the determination of the accurate partitioning of the precipitation into evapotransporation and runoff, estimation of subsurface water storages, identifying source areas in large water catchments, etc.
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 1847 Modeling
DE: 1855 Remote sensing (1640)
SC: Hydrology [H]
MN: 2007 Fall Meeting