THE POTENTIAL FOR ACCELERATED GLOBAL SEA LEVEL RISE DUE TO ANTHROPOGENIC CLIMATE WARMING IS A SIGNIFICANT SOCIETAL PROBLEM. MELTING OF THE ICE SHEETS IS THE LARGEST POTENTIAL CONTRIBUTOR TO GLOBAL SEA-LEVEL RISE AND THE STABILITY OF THE ANTARCTIC ICE SHEET IS ESPECIALLY CRITICAL BECAUSE A SMALL RELATIVE CHANGE IN ITS MASS CAN LEAD TO A LARGE CHANGE IN SEA-LEVEL. EVIDENCE EXISTS OF ACCELERATED ICE-SHEET ABLATION DURING THE PAST DECADE, AND ANTARCTICA MAY BECOME THE LARGEST CONTRIBUTOR TO SEA-LEVEL RISE DURING THE 21ST CENTURY. THE CONTEMPORARY (1992-2007) ANTARCTIC MASS BALANCE ESTIMATE HAS A WIDE RANGE, EQUIVALENT TO A -0.12 TO +0.40 MM/YR CONTRIBUTION TO SEA LEVEL, AND IT IS CRITICAL TO NARROW THIS UNCERTAINTY. IN PARTICULAR, SATELLITE RADAR ALTIMETRY (1992-2004) ESTIMATES THAT THE ANTARCTIC ICE-SHEET IS NEAR BALANCE, WHILE GRACE GRAVIMETRY (2002-2007) AND MASS BUDGET OBSERVATIONS FROM INSAR (2006) ESTIMATE MASS LOSS OF UP TO 150 GTON/YR (0.40 MM/YR SEA LEVEL RISE). EACH OF THESE METHODS HAS ITS OWN UNIQUE SOURCES OF UNCERTAINTIES THAT, WHEN APPLIED INDEPENDENTLY, YIELD ESTIMATES WITH LARGE DISCREPANCIES THAT ARE DIFFICULT TO RECONCILE. HOWEVER, SOURCES OF UNCERTAINTY ARE LARGELY COMPLEMENTARY BETWEEN METHODS. THUS, WE PROPOSE AN INTEGRATIVE APPROACH TO DETERMINE ICE-SHEET MASS BALANCE, FOR THE FIRST TIME, BY COMBINING MULTIPLE LASER/RADAR ALTIMETRY (ICESAT, AND ENVISAT/CRYOSAT), GRACE, AND SURFACE MASS BALANCE (SMB) MODELS IN CONCERT WITH EACH OTHER. THIS APPROACH WILL ALLOW FOR VALIDATION OF RESULTS USING INDEPENDENT OBSERVATIONS, AND ALLOW FOR IMPROVED CONSTRAINTS ON THE EFFECTS OF ISOSTASY, FIRN COMPACTION RATES AND SURFACE PROPERTIES THROUGH SENSOR AND MODEL INTER-COMPARISON. OUR ULTIMATE OBJECTIVE IS TO GENERATE AN IMPROVED, SPATIALLY RESOLVED, COMPOSITE -20-YEAR (1992-2010) ANTARCTIC ICE-SHEET MASS BALANCE TIME SERIES. IN THE COURSE OF THIS WORK, WE WILL DEVELOP COORDINATED USE OF ALTIMETRY, GRAVITY AND 5MB DATA FOR LONG-TERM ICE SHEET MASS BALANCE MONITORING.