A LONG-TERM SCALABLE TESTBED NETWORK WITH UNIFORM AND COMPREHENSIVE INSTRUMENTATION OF THE LAND-ATMOSPHERE CONTINUUM FROM BEDROCK TO BOUNDARY LAYER IS NEEDED TO ENHANCE HYDROLOGICAL MODELING AND STRATEGICALLY INTEGRATE NASA REMOTELY SENSED PRODUCTS WITHIN THE MODELING FRAMEWORK. LAND-ATMOSPHERE COUPLING IS A MAJOR CHALLENGE IN MULTIPLE DISCIPLINES WHICH CANNOT BE SUFFICIENTLY ADDRESSED THROUGH TRADITIONAL LIMITED-AREA/DURATION AND UNIVARIATE AIRBORNE AND GROUND CALIBRATION/VALIDATION CAMPAIGNS. FIELD CAMPAIGNS ARE CONSTRAINED IN THEIR INEFFECTIVE REPRESENTATION OF LOCAL GEOGRAPHY TOPOGRAPHY AND ECOLOGY WHICH IS FURTHER COMPOUNDED BY HYDROCLIMATIC VARIABILITY. THIS PROPOSAL IS FOR FUNDING OF A MULTI-DISCIPLINARY MULTI-AGENCY AND MULTI-NATIONAL TEAM TO DESIGN A LAND-ATMOSPHERE OBSERVING TESTBED THAT WILL ADDRESS THE NEEDS OF THE BROAD ECOHYDROLOGICAL REMOTE SENSING MODELING AND FORECASTING COMMUNITIES. THE TESTBED WILL: 1) MEET THE CALIBRATION/VALIDATION NEEDS OF NASA S CURRENT AND FUTURE (NEXT DECADAL) TERRESTRIAL HYDROLOGY-RELATED EARTH OBSERVING MISSIONS AND MODELS 2) FILL OBSERVATIONAL GAPS DEEMED CRITICAL TO ADDRESSING OPEN PROCESS-RELATED SCIENCE QUESTIONS AND 3) INCREASE THE SKILL AND OVERALL APPLICATION OF NASA DATA AND MODELS TOWARDS ADDRESSING CURRENT AND FUTURE PRIORITY SCIENCE QUESTIONS ACROSS THE MULTIDISCIPLINARY EARTH SYSTEM MODELING COMMUNITY.