SCIENTIFIC/TECHNICAL/MANAGEMENT MARS HAS A MASSIVE UP TO 1 KM-THICK CO2 ICE DEPOSIT BURIED BENEATH A ~10 M-THICK LAYER OF H2O ICE AT ITS SOUTH POLE. IF RELEASED THE BURIED CO2 ICE COULD DOUBLE MARS ATMOSPHERIC PRESSURE AND SIGNIFICANTLY ALTER MARS CLIMATE. THE BURIED CO2 ICE DEPOSIT ARISES FROM DEPOSITION OF ATMOSPHERIC CO2 AT TIMES OF LOW OBLIQUITY (LESS POLAR SUNLIGHT) THAT IS SUBSEQUENTLY BURIED BY A LAYER OF H2O ICE. THE MANNER AND FREQUENCY IN WHICH THE BURIED CO2 IS RELEASED INTO THE ATMOSPHERE IS AN OPEN QUESTION WITH PROFOUND IMPLICATIONS FOR MARS CLIMATE. ONE HYPOTHESIS PROPOSES THAT THE H2O ICE LAYER IS PERMEABLE TO CO2 GAS FLOW SUCH THAT THE BURIED CO2 FREELY AND GRADUALLY EQUILIBRATES WITH THE ATMOSPHERE AS MARS OBLIQUITY EVOLVES. AN ALTERNATIVE HYPOTHESIS PROPOSES THAT THE H2O LAYER PHYSICALLY AND THERMALLY SEQUESTERS THE BURIED CO2 FROM THE ATMOSPHERE SUCH THAT THE BURIED CO2 IS RELEASED ONLY RARELY WHEN THE H2O LAYER IS ABLATED AT TIMES OF CRITICALLY HIGH OBLIQUITY. IMPORTANTLY MARS MEAN PRESSURE THROUGHOUT ALL OF THE AMAZONIAN WOULD BE SIGNIFICANTLY LOWER IF H2O ICE LAYERS TYPICALLY SEQUESTER A PORTION OF MARS CO2 INVENTORY AS BURIED CO2 ICE. THUS DETERMINING WHETHER H2O LAYERS SEQUESTER THE BURIED CO2 HAS SIGNIFICANT CONSEQUENCES FOR UNDERSTANDING AMAZONIAN MARS CLIMATE HABITABILITY AND SURFACE GEOLOGIC PROCESSES. EACH OF THE TWO HYPOTHESES PREDICTS DIFFERENT MORPHOLOGIC DEVELOPMENT AND SEASONAL TEMPERATURE BEHAVIOR OF THE H2O ICE LAYER. THEREFORE WE WILL ANALYZE THE MORPHOLOGIC AND THERMAL CHARACTERISTICS OF THE H2O ICE LAYER IN ORDER TO DETERMINE WHETHER THE H2O ICE LAYER SEQUESTERS THE BURIED CO2. METHODOLOGY TO ACHIEVE OUR GOAL WE WILL: 1. USE CONTEXT CAMERA (CTX) AND HIGH-RESOLUTION IMAGING SCIENCE EXPERIMENT (HIRISE) IMAGES AND DIGITAL TERRAIN MODELS TO MAP THE MORPHOLOGY AND STRUCTURE OF THE TOPMOST H2O LAYER. 2. USE CTX TO OBSERVE THE SPATIOTEMPORAL EXPOSURE OF THE H2O LAYER THROUGH OVERLYING SEASONAL CO2 FROST AND HOLES IN THE RSPC COUPLED WITH THERMAL EMISSION IMAGING SYSTEM (THEMIS) DATA TO MAP THE SEASONAL TEMPERATURE CYCLE OF THE EXPOSED H2O REGIONS. 3. QUANTITATIVELY MODEL THE MORPHOLOGICAL DEVELOPMENT OF THE H2O LAYER AND HEAT TRANSFER THROUGH THE H2O LAYER MATCHED TO OBSERVATION TO DETERMINE WHETHER CO2 SUBLIMES THROUGH THE H2O LAYER. 4. MODEL SINTERING RATES OF THE H2O LAYER BASED ON THE OBSERVED THERMAL ENVIRONMENT TO DETERMINE WHETHER THE H2O LAYER WILL BECOME IMPERMEABLE TO CO2 GAS FLOW. RELEVANCE TO MARS DATA ANALYSIS PROGRAM (MDAP) ROSES 2020 CALL C.9 (MARS DATA ANALYSIS) STATES THAT THE OBJECTIVE OF THE MARS DATA ANALYSIS PROGRAM (MDAP) IS TO ENHANCE THE SCIENTIFIC RETURN FROM MISSIONS TO MARS CONDUCTED BY NASA AND OTHER SPACE AGENCIES [ INCLUDING] MARS ODYSSEY (MO) [AND] MARS RECONNAISSANCE ORBITER (MRO). OUR PROPOSED WORK WILL EXTENSIVELY USE OBSERVATIONS FROM THE HIRISE AND CTX INSTRUMENTS ONBOARD MRO AND THE THEMIS INSTRUMENT ONBOARD MO THEREBY ENHANCING THEIR SCIENTIFIC RETURN. ROSES 2020 CALL C.9 ALSO STATES THAT TASKS RESPONSIVE TO THIS CALL INCLUDE 1) DATA ANALYSIS TASKS [AND] 2) NONDATA-ANALYSIS TASKS THAT ARE NECESSARY TO ANALYZE OR INTERPRET THE DATA THESE TASKS MAY INCORPORATE THEORY MODELING LABORATORY STUDIES CORRELATIVE ANALYSES AND/OR OTHER RESEARCH AS LONG AS THE PRIMARY FOCUS OF THE WORK IS DATA ANALYSIS. OUR RESEARCH PLAN IS TO OBSERVE THE MORPHOLOGY AND TEMPERATURE CYCLE OF THE TOPMOST H2O LAYER OF MARS MCID AND THEN INTERPRET OUR OBSERVATIONS USING NUMERICAL MODELING. THE PROPOSED WORK INVOLVES 80% EFFORT FOR DATA ANALYSIS TASKS AND 20% SUPPORTING MODELING WORK AND IS THEREFORE RESPONSIVE TO MDAP RATHER THAN SOLAR SYSTEM WORKINGS BECAUSE ROSES 2020 CALL C.3 (SOLAR SYSTEM WORKINGS) STATES THAT "SOLAR SYSTEM WORKINGS DOES NOT ACCEPT PROPOSALS