CLIMATE CHANGE IS IMPACTING THE TIMING AND DURATION OF VEGETATION PHENOLOGY AT REGIONAL TO GLOBAL SPATIAL SCALES AND AT SUBSEASONAL TO DECADAL TIME SCALES. THESE CHANGES HAVE PROFOUND IMPLICATIONS FOR A WIDE RANGE OF ECOLOGICAL AND BIOSPHERE-ATMOSPHERE INTERACTIONS THAT ARE COUPLED TO THE CLIMATE SYSTEM. RESULTS FROM STUDIES USING TIME SERIES OF AVRRR IMAGERY HAVE PROVIDED PATHBREAKING INSIGHTS REGARDING HOW LARGE-SCALE ECOSYSTEM PHENOLOGY IS BEING ALTERED BY CLIMATE CHANGE. HOWEVER ISSUES RELATED TO THE RADIOMETRIC QUALITY SPATIAL RESOLUTION AND GEO-LOCATION ACCURACY OF AVHRR DATA IMPOSES SUBSTANTIAL LIMITATIONS ON THE CHARACTER AND QUALITY OF INFERENCES REGARDING ECOSYSTEM CHANGES THAT CAN BE MADE FROM THESE DATA. OUR ANALYSIS FOCUSES ON MEASUREMENTS OF LAND SURFACE PHENOLOGY (LSP) BECAUSE THEY PROVIDE FUNDAMENTAL INFORMATION RELATED TO LONG-TERM SEASONAL AND SUB-SEASONAL DYNAMICS IN TERRESTRIAL ECOSYSTEMS IN RESPONSE TO CLIMATE VARIABILITY. TO EXPLORE HOW OBSERVED LSP CHANGES BOTH RESPOND TO CLIMATE FORCING AND CAPTURE CHANGES IN ECOSYSTEM FUNCTION WE WILL LINK OBSERVED DYNAMICS IN LSP TO CORRESPONDING VARIATION IN: (1) CLIMATE FORCING FROM GLOBAL REANALYSIS DATASETS (2) CARBON FLUXES AND MICRO-METEOROLOGICAL MEASUREMENTS FROM EDDY COVARIANCE NETWORKS AND (3) MODIS LAND SURFACE TEMPERATURE. RESULTS FROM THIS WORK WILL PROVIDE A ROBUST ANALYSIS OF VARIATION AND TRENDS IN GLOBAL PHENOLOGY OVER THE PAST TWO DECADES CHARACTERIZE AND QUANTIFY THE MAGNITUDE AND SENSITIVITY OF ECOSYSTEM-SCALE CARBON FLUXES TO VARIATION IN PHENOLOGY PROVIDE INSIGHTS INTO THE UNDERSTUDIED EFFECTS OF DROUGHT ON PHENOLOGY AND YIELD REFINED AND IMPROVED UNDERSTANDING OF THE LIKELY FUTURE CHANGES IN PHENOLOGY ARISING FROM CLIMATE CHANGE.