Airborne multispectral images were collected on 2 days during the First ISLSCP Field Experiment (FIFE) to investigate the time and space variability of remotely sensed geophysical parameters over the study region. The data sets consisted of multiple overflights covering about a 60-min period during late morning on June 4, 1987, and shortly after dark on the following day. Image data from each overpass were calibrated and Earth-located with respect to each other using aircraft inertial navigation system parameters and ground control points. Normalized difference vegetation index (NDVI) values were generated from visible and near-infrared imagery to characterize the greenness of the vegetation, its variation with changing sensor-Sun-viewing geometries. Land surface temperatures (LST) were derived using a split-window formulation to investigate their spatial and temporal variability in relation to the NDVI values and other surface features and the variability between day and night observations. The results indicated the large variations in these parameters existed at small scales. Variability in NDVI values was large and were governed by the natural surface character and its use.

Large variations of NDVI occurred with different sensor-Sun-viewing geometries as a result of anisotropic reflection from the surface, atmospheric interference, and slope and aspect effects. LST was also highly varied. Positive land surface temperature changes, as a result of excess absorption of solar radiation, exceeded 4¿C in 45 min over certain regions and were governed by land use and microtopography. Smaller negative temperature changes were observed at night. NDVI and LST values were inversely related with high correlations for certain surface features. The unique multispectral atmospheric mapping sensor (MAMS) measurements and the derived NDVI and LST data provided a better understanding of reflective and thermal properties within a heterogeneous region, as well as a quantitative description of their spatial and temporal variability, and served to better characterize important surface processes related to microclimate variability. ¿American Geophysical Union 1992