Covariance of biophysical data with digital topographic and land use maps over the FIFE site

Sampling design is critical in locating ground sampling stations for large-scale climatological field experiments. In the stratified sampling design adopted for the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), the study region was stratified into 14 different terrain units based on land use/land cover and topographic variables that were hypothe-sized to have a strong influence on surface biophysical properties. Digital terrain maps were produced to facilitate ground data integration and extrapolation. This paper describes the biophysical stratifi-cation of the FIFE site, implementation of the stratification using geographic information system (GIS) techniques, and validation of the stratification with respect to field measurements of biomass, soil moisture, Bowen ratio (/3), and the greenness vegetation index (GVI) derived from thematic mapper satellite data. Maps of burning and topographic position were significantly associated with variation in biomass, GVI, and /3. The effects of burning and topography were stronger for the Konza Prairie Long-Term Ecological Research (KPLTER) site than for the rest of the FIFE site, where cattle grazing was a major confounding effect. The stratified design did not appreciably change the estimated site-wide means for surface climate parameters but accounted for between 25 and 45 % of the sample variance depending on the variable. The design was weakened by undersampling of several strata, b