MID-20TH CENTURY ICE HEIGHTS FROM ARCHIVED ANTARCTIC AERIAL PHOTOGRAPHYUNDERSTANDING HOW THE ANTARCTIC ICE SHEET OPERATES IS VITAL CHANGES THERE AFFECT GLOBAL SEA LEVEL THERMOHALINE CIRCULATION AND CLIMATE AND WEATHER PATTERNS. NUMERICAL MODELS WITH REALISTIC PHYSICS MAKE IT POSSIBLE TO DECIPHER THE PROCESSES AND PHENOMENA THAT CONTROL THE BEHAVIOR OF THE ICE SHEET. ADVANCEMENTS IN BOTH ICE SHEET AND GLACIAL ISOSTATIC ADJUSTMENT (GIA) MODELING HAVE BEEN HAMPEREDBY A LACK OF DATA WITH WHICH TO CONSTRAIN AND VALIDATE THE MODELS. ANTARCTICA IS UNDER-SAMPLED AND THE ADDITION OF EVEN A FEW DATA POINTS CAN RADICALLY RE-SHAPE OUR VIEW OF THE ICE SHEET AS A WHOLE. CONFIDENCE IN PREDICTIONS ON HOW THE CONFIGURATION OF THE ANTARCTIC ICE SHEET IS LIKELY TO EVOLVE IN THE NEAR FUTURE UNDER VARIOUS WARMING SCENARIOS WILL IMPROVE WITH NEW DATA ASSIMILATION AND VALIDATIONSOURCES THAT WE WILL PROVIDE. UNDERSTANDING THE ANTARCTIC IS CRITICAL TO UNDERSTANDING THE EARTH SYSTEM A CORE MISSION OF NASA.OUR WORK WILL PRODUCE A NOVEL ANTARCTIC ICE-HEIGHT DATA SOURCE DERIVED FROM ARCHIVED AERIAL PHOTOGRAPHY COLLECTED BETWEEN 1946 AND THE LATE 1990S. THESE ELEVATION DATA WILL BE USED TO ASCERTAIN HOW PARTS OF THE ANTARCTIC ICE SHEET HAVE CHANGED OVER THE LAST 15 TO 70 YEARS. THE ELEVATION DATA WILL BE ASSIMILATED INTO COUPLED ATMOSPHERIC/ICE-SHEET MODELS AND CAN ALSO BE USED BY INPUT TO ICE-HISTORY/EARTH RHEOLOGY GIA MODELS. OUR DATA WILL ALLOW THE ICE SHEET MODELING COMMUNITY TO IMPROVE MODEL SKILL AND REDUCE THE UNCERTAINTIES ON THE PROGNOSTIC MODEL OUTPUT. IMPROVED MODELS WILL HELP PREDICT THE FUTURE BEHAVIOR OF ANTARCTICA ALLOWING ASSESSMENT OF HOW CLOSE COMPONENTS OF THE ANTARCTIC SYSTEM ARE TO GLACIOLOGICAL TIPPING POINTS AND PROVIDE MORE PRECISE EXAMINATION OF THE THREAT OFACCELERATED SEA LEVEL RISE IN THE NEAR TERM.THE MID 20TH CENTURY ELEVATION DATA SET WILL ALLOW CLOSE INSPECTION OF REGIONAL ICE MASS CHANGES AND ICE FRONT INSTABILITY ALONG THE COAST OF WEST ANTARCTICA THE TRANSANTARTIC MOUNTAINS AND AROUND BEDROCK OUTCROPS EVERYWHERE ELSE IN ANTARCTICA WHERE THERE IS SUFFICIENT AND USEABLE ARCHIVED AERIAL PHOTOGRAPHY. THIS EXAMINATION WILL LET US TEST OUR MAIN QUESTION: ARE RECENT ANTARCTIC ICE MASSLOSS RATES ESPECIALLY IN THE AMUNDSEN SEA EMBAYMENT EXCEPTIONAL COMPARED TO AVERAGE MASS LOSS RATES OVER THE LAST 50-70 YEARS? THE PROJECT RELIES ON THE MELDING OF NEW TECHNOLOGY AND OLD DATA AND IS LEVERAGED BY THE WHOLESALE SCANNING OF ANALOGUE PHOTOGRAPHS FROM EXPEDITIONS THAT OCCURRED BETWEEN THE MID-1940S THROUGH THE EARLY 1990S; THE AVAILABILITY OF SUB-METER RESOLUTION SATELLITE IMAGERY;ALONG-TRACK STEREO SATELLITE DERIVED METER-SCALE TOPOGRAPHY; ADVANCES IN COMPUTER VISION AND STRUCTURE FROM MOTION ALGORITHMS; AND REMOTELY SENSED GROUND CONTROL DATA AVAILABLE FROM THE NASA ICESAT AND ICEBRIDGE MISSIONS SUPPLEMENTED WITH ESA CRYOSAT-2 DATA WHERE NECESSARY.THE PROJECT WILL:1) CREATE A DATABASE OF TIME-TAGGED ICE AND BEDROCK HIGH-RESOLUTION DIGITAL ELEVATION MODELS (DEMS)2) CO-REGISTER THE DERIVED DEMS TO EXISTING SOURCES OF GROUND CONTROL SUCH AS ICESAT AIRBORNE TOPOGRAPHIC MAPPER (ATM) AND LAND VEGETATION AND ICE SENSOR (LVIS) LASER ALTIMETRY USING TIE POINTS OVER PROMINENT BEDROCK FEATURES .3) ORTHORECTIFY THE SUB-METER SATELLITE IMAGERY TO THE HIGH-RESOLUTION DEMS.4) USE AFFINE SCALE INVARIANT FEATURE TRACKING (ASIFT) ALGORITHMS TO CO-REGISTER AERIAL PHOTOGRAPHY TO ORTHORECTIFIED SUB-METER SATELLITE IMAGERY. THIS WILL PROVIDE GROUND CONTROL FOR THE AERIAL PHOTOGRAPHY.5) USE A TWO PRONGED APPROACH USING STRUCTURE FROM MOTION ALGORITHMS AND STEREO-PHOTOGRAMMETRY ASSISTED WITH THE GROUND CONTROL TO PRODUCE DEMS FROM MID-CENTURY AERIAL PHOTOGRAPHY.6) PRODUCE ICE HEIGHT CHANGE TIME-SERIES AT MANY HUNDREDS OF LOCATIONS AROUND ANTARCTICA. EXAMINE THESE FOR PATTERNS THAT ARE INDICATE COMMON FORCING FACTORS.7) ASSIMILATE MID-CENTURY ICE GEOMETRY INTO COUPLED ATMOSPHERIC/ICE-SHEET MODELS.8) MAKE ELEVAT