APPLIED RESEARCH LABORATORIES THE UNIVERSITY OF TEXAS AT AUSTIN (ARL:UT) PROPOSES TO WORK WITH THE JET PROPULSION LABORATORY (JPL) TO DEVELOP A METHODOLOGY TO CONVERT THE ICESAT-2 VEGETATION HEIGHT MEASUREMENTS TO ABOVEGROUND STRUCTURE AND BIOMASS ALONG WITH ASSOCIATED UNCERTAINTY. ONE LIMITATION OF ICESAT-2 IS THAT THE MEASUREMENTS ARE COLLECTED IN A PROFILING MANNER AND THERE IS NOT WALL-TO-WALL SAMPLING OF LIDAR DATA EVEN AT HIGHER LATITUDES. IN THIS PROPOSAL WE WILL PROVIDE A SYNERGISTIC APPROACH TO COMBINE THE ICESAT-2 CANOPY HEIGHT MEASUREMENTS AND BIOMASS ESTIMATES WITH SATELLITE L-BAND RADAR MEASUREMENTS TO MAP FOREST BIOMASS DENSITY OVER A VARIETY OF GLOBAL ECOSYSTEMS WITH LOW BIOMASS DENSITY (<100 MG/HA). WHEN BUILDING A METHODOLOGY TO ESTIMATE BIOMASS ACROSS A LANDSCAPE IT IS CRITICAL TO QUANTIFY THE ERRORS AND UNCERTAINTIES ASSOCIATED WITH THE PROPOSED DATA PRODUCTS. ASSOCIATED WITH THIS EFFORT WE INTEND TO CHARACTERIZE THE UNCERTAINTY FROM THE PHOTON LEVEL TO THE ICESAT-2/ATL08 DATA PRODUCT LEVEL TO THE ESTIMATED BIOMASS FOR THE ICESAT-2 DATA AND FINALLY THE SCALED UP BIOMASS ESTIMATES USING RADAR. THE PROPOSED RESEARCH WILL FOCUS ON SEVERAL SITES WITH EXISTING GROUND AND AIRBORNE LIDAR OBSERVATIONS SUCH AS BOREAL FORESTS (ARCTIC BOREAL VULNERABILITY EXPERIMENT OR ABOVE STUDY DOMAIN) WOODLAND SAVANNA AND DRY FORESTS IN TANZANIA AND MEXICO TEMPERATE FRAGMENTED AND SECONDARY FORESTS IN THE US AND SECONDARY AND DEGRADED FORESTS IN HUMID TROPICAL FORESTS IN THE AMAZON BASIN (BRAZIL). BY FUSING ICESAT-2 BIOMASS ESTIMATES WITH NASA-ISRO SAR MISSION (NISAR) A COMPLETE AND MORE ACCURATE REPRESENTATION BIOMASS IS FEASIBLE FOR LOW BIOMASS ECOSYSTEMS. THE NISAR RADAR MISSION IS SET TO LAUNCH IN 2020 THUS PROVIDING SUFFICIENT TIME TO DEVELOP A METHODOLOGY TO FUSE ICESAT-2 BIOMASS ESTIMATES WITH RADAR TO PROVIDE WALL-TO-WALL BIOMASS ESTIMATES FOR LOW BIOMASS ECOSYSTEMS SUCH AS BOREAL FOREST AND WOODED SAVANNAS. UNTIL THE LAUNCH OF THE NISAR MISSION WE WILL USE ADVANCED LAND OBSERVATION SATELLITE - PHASED ARRAY TYPE L-BAND SYNTHETIC APERTURE RADAR (ALOS PALSAR) DATA OVER SELECTED AREAS AS A SURROGATE FOR NISAR RADAR DATA.