Geoff Henebry and Alan Knapp, Konza Prairie Research Natural Area LTER, have been awarded a National Science Foundation intersite grant for a project that uses Synthetic Aperture Radar (SAR) data from European, Canadian and Japanese orbital platforms to address synoptically the spatio-temporal variation in canopy and soil moisture and their ecological consequences.
The SAR imagery is being provided through data grants from NASA and the European Space Agency. These data augment current investigations at Konza and Sevilleta National Wildlife Refuge LTER. Both sites are located within ecotones in which soil moisture is a major determinant of plant productivity and species composition. The primary products will be site-specific time series of soil moisture and canopy change maps. These spatio-temporal data will then be used for several distinct objectives all aimed at improving scene models that link remote sensing and ground truth-level data with ecological processes.
At Konza, the working hypothesis is that temporal shifts of spatial patterns in SAR imagery of prairie landscapes can reveal topoedaphic constraints on soil moisture availability, which translate into constraints on the productivity of the vegetation and which, in turn, are expressed in terms of the structure of a maturing canopy.
At Sevilleta, of particular interest are the effects of the El Nino Southern Oscillation as it modulates the amount of annual and seasonal precipitation and thereby available soil moisture, plant production, nutrient cycling, and animal abundance. SAR imagery enables the mapping of soil moisture across the site for parameterization, calibration, and validation of spatially-explicit soil water balance models. Segmentation of SAR image series will facilitate landscape classification of this large and diverse study area. Cross-site objectives include comparative analysis of image series using robust spatial metrics to refine change detection and quantification algorithms and to compare at the landscape level the responsiveness and sensitivity of ecological processes and patterns to climatic fluctuations.
Geoff Henebry, Konza Prairie