Southern Great Plains 1994 Hydrology Experiment

Project Description
SGP97 was originally conceived as an airborne experiment for daily mapping of surface soil moisture. In expanding its scope to meet interdisciplinary interests, the main considerations in the experimental design have been (1) maintaining as much spatial airborne coverage as possible on a daily basis; (2) nesting when- and where-ever possible to allow observations at a hierarchy of scales; and (3) making maximum use of existing facilities in the area.

The core of this project is the large scale aircraft soil moisture mapping. Within logistic and fiscal constraints, this experiment will attempt to map surface soil moisture over an area of ~10,000 km2 (order of magnitude larger than previously observed) at a spatial resolution compatible with known data interpretation algorithms (~1 km). The resulting data base would allow the scaling up to projected satellite sized footprints (~10 km) and cover an area large enough to provide over 100 pixels of this size. These data would allow the examination of the information content of coarse resolution data as well as the analysis of the spatial/temporal scales generally utilized in hydrological and hydrometerological models. We will attempt temporal coverage on a daily basis over a period of one month.

Data will be collected using an L band passive microwave mapping instrument called ESTAR which will be flown on a P-3 aircraft. In addition to the L band system, a single beam thermal infrared sensor and a dual polarization C band microwave radiometer will be flown.

The temporal analysis will be enhanced by making continuous 24-hour observations using a truck based microwave radiometer system to complement the once-a-day aircraft measurements. This system consists of L, S, and C band single polarization instruments as well as thermal infrared. It would be located at the DOE ARM CART Central Facility which will provide the most comprehensive temporal observations.

The boundary layer component of SGP97 is configured to primarily evaluate the influence of soil moisture on the local surface energy budget and the influence of mesoscale variability in the surface energy budget on the development of convective boundary layer. To the extent possible, attempts will be made to quantify the water vapor budget of the boundary layer (advection, entrainment, and evapotranspiration) using remotely sensed and in situ data.

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