Organization: National Aeronautics and Space Administration (NASA)

Research Title: Land Surface Hydrology

Funding Level (millions of dollars):

FY94 2.7
FY95 2.2
FY96 2.7

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Research Subcommittee (100%)
(b) Environmental Issue: Natural variability (75%); Large-scale changes in land-use (15%); Water availability and allocation (10%)
(c) Research Activity: System structure and function: Observations (20%); Understanding (80%)

Organizational Component:
Science Division
Office of Mission to Planet Earth
NASA Headquarters
Washington, DC 20546

Point of Contact:
Ming Ying Wei
Phone: 202-358-0771

Research Goals:
To develop understanding, modeling and prediction of continental water cycle processes, with particular emphasis on remote sensing and four-dimensional data assimilation of precipitation and soil moisture.

Research Description:
NASA's Water Cycle Processes Program supports research in three interweaving categories aimed at improving the observation and theory of continental water cycle processes which contribute to the variability of the ocean-atmosphere-land system; the categories are:

Observational studies of hydrologic variables, e.g. precipitation, soil moisture (40%).

Diagnostic and analytical studies of land surface hydrology and land-atmosphere exchange of energy and water (40%), including scaling of the dynamic behavior of the atmospheric boundary layer and land surface water and energy balance in both freezing (snow and ice) and non-freezing environments, in the presence of topography.

Development of coupled meteorological-hydrological models, including four- dimensional data assimilation techniques (20%), with emphasis on the reciprocal influences between regional and global climate and land cover/use change.

Program Interfaces:
WCRP's GEWEX Continental-scale International Project (GCIP), the International Satellite Land-Surface Climatology Project (ISLSCP), and IGBP's Biological Aspect of Hydrological Cycle (BAHC).

Program Milestones:
January 1994: Soil Moisture Workshop conducted in Tiburon, CA; feasibility project of data assimilation for soil moisture initiated in 1995.

Policy Payoffs:
(a) A demonstration of an observational strategy for soil climate based on the combined use of remote sensing and in situ data and physically--based models, a technique well exploited in meteorology and, to some extent, oceanography. (b) Provision of process-level understanding to global water cycle and Earth System modeling and prediction. (c) A better scientific basis for assessing consequences of changes in land and water management (e.g., irrigation, deforestation). (d) Provision of timely information for agricultural planning.