Jornada experimental range: A unique arid land location for experiments tovalidate satellite systems

The Jornada Experimental Range (Jornada) in southern New Mexico provides a unique opportunity to use remote sensing techniques to study arid rangeland and the responses of vegetation to changing hydrologic fluxes and atmosphe ric driving forces. Research by the United States Department of Agriculture Forest Service and Agricultural Research Service at Jornada has been conti nuous since 1912. The Jornada has been a National Science Foundation Long-T erm Ecological Research site since 1981. These long-term investigations hav e provided ground data on vegetation characteristics, ecosystem dynamics, a nd vegetation response to changing physical and biological conditions. To c omplement the programs of ground measurements, a campaign called JORNEX (JO RNada EXperiment) began in 1995 to collect remotely sensed data from aircra ft and satellite platforms to provide spatial and temporal data on physical : and biological states of the Jornada rangeland. A wide range of ground, a ircraft, and satellite data have been collected on the physical, vegetative , thermal, and radiometric properties of three ecosystems (grass, grass/shr ub transition, and shrub) typical of the Jornada rangeland and of southwest ern U.S, deserts. Spatial surface energy balance estimates were made from a combination of parameters and state variables estimated from aircraft and ground data. Landscape surface roughness was evaluated with the laser altim etry data and used to estimate aerodynamic roughness. Data from different p latforms allowed the evaluation of the landscape at different scales. These measurements are being used to quantity hydrologic budgets and plant respo nses to change in components in the water and energy balance at the Jornada . Published by Elsevier Science Inc.