THE GOAL OF THIS PROPOSAL IS TO DEVELOP A BETTER UNDERSTANDING OF HOW SURFACE SOURCES AND SINKS OF WATER AT THE MARTIAN POLES INTERACT WITH THE GLOBAL CLIMATE SYSTEM. THE PROPOSAL WILL PRIMARILY USE DATA PRODUCTS FROM CRISM MCS AND MARCI ABOARD MRO. A MAJOR CONTRIBUTION OF THIS PROPOSAL WILL BE IN THE THERMAL AND METEOROLOGICAL MODELING "NECESSARY TO ANALYZE OR INTERPRET THE DATA" IN TERMS OF THE WATER AND DUST CYCLES. THIS PROPOSAL SEEKS TO ADDRESS FOUR MAJOR QUESTIONS: - HOW IS THE LOCAL CYCLE OF WATER (AND DUST) CONTROLLED AT SITES OBSERVED BY CRISM/MCS/MARCI? - CAN SUCH AN UNDERSTANDING OF THE CONTROLS ON SURFACE WATER EXCHANGE BE SUMMARIZED INTO A PROGNOSTIC FRAMEWORK LIKE A LAND SURFACE MODEL (LSM) IN TERRESTRIAL STUDIES? - HOW IS THE GLOBAL CYCLE OF WATER AND DUST CHANGED IF BETTER REPRESENTATIONS OF THE POLAR EXCHANGE PROCESSES ARE INCLUDED IN GLOBAL MODELS? - CAN THE SEASONAL PROGNOSTIC PICTURE OF ICE AND DUST DEPOSITION AT THE POLES BE USED TO HELP UNDERSTAND THE FORMATION OF POLAR LAYERED TERRAIN? THE LATTER QUESTION SPECIFICALLY ADDRESSES THE MDAP CALL REGARDING "NONDATA-ANALYSIS TASKS THAT SIGNIFICANTLY ENHANCE THE USE OR FACILITATE THE INTERPRETATION OF MISSION DATA" AS IT ALLOWS DATA ON CURRENT PROCESSES TO BE USED TO ADDRESS LONGER-TERM QUESTIONS IN MARTIAN CLIMATE DYNAMICS AND GEOLOGY. THE WATER CYCLE IS A MAJOR COMPONENT OF THE MARTIAN CLIMATE SYSTEM YIELDING A SIGNIFICANT FEEDBACK ON THE CLIMATE THROUGH ITS EFFECTS ON SURFACE ALBEDO VIA FORMATION OF ICES AND ON ATMOSPHERIC EMISSIVITY AND REFLECTIVITY VIA CLOUDS. CLOUDS ALSO INTERACT WITH THE ATMOSPHERIC DUST DISTRIBUTION VIA THE MICROPHYSICS OF CLOUD PARTICLE EVOLUTION YIELDING ADDITIONAL MODIFICATION OF ATMOSPHERIC RADIATIVE FORCING. WHILE THE MAJOR PROCESSES OF THE WATER CYCLE AND ITS INTERACTIONS WITH THE DUST AND CO2 CYCLES HAVE BEEN SKETCHED IN OUTLINE FOR SEVERAL DECADES THE SPECIFICS OF HOW THE WATER CYCLE IS CONTROLLED REMAIN UNCERTAIN E.G. THE IMPORTANCE OF REGOLITH EXCHANGE. THE NATURE OF THE NORTHERN CAP AS A DOMINANT WATER SOURCE AND THAT OF BOTH THE NORTH AND THE SOUTH AS SINKS AGAIN SEEMS CERTAIN IN OUTLINE BUT THE DETAILS OF HOW THESE SOURCES AND SINKS FUNCTION HAS NOT RECEIVED MUCH ATTENTION AND MAY DOMINATE THE EFFICACY OF HOW THE WATER (AND RELATED CLIMATE) CYCLES ARE CONTROLLED GLOBALLY. CRISM DATA SUGGEST SIGNIFICANT LOCAL CYCLING AND IN SOME CASES BURIAL OF ANNUAL WATER LAYERS WHICH IS LIKELY THE BASIS FOR POLAR LAYER FORMATION AN UNDERSTANDING OF WHICH WOULD BE KEY TO UNRAVELING THE RECORD OF CLIMATE STORED IN THESE LAYERS. WE PROPOSE TO USE THE PLANETWRF MODELING SYSTEM TO UNDERTAKE IDEALIZED LOCAL THERMAL / WATER EXCHANGE MODELING OF SPECIFIC SITES OBSERVED BY CRISM TO UNDERTAKE RESOLVED-SCALE SEASONAL MODELING OF THE NORTHERN AND SOUTHERN CAPS AND TO UNDERTAKE MULTI-ANNUAL MODELING OF THE CLIMATE SYSTEM USING LSM SCHEMES DEVELOPED WITHIN THIS PROJECT. NEW DATA PRODUCTS FROM CRISM WILL BE DEVELOPED AS NEEDED WITHIN THE ANALYSIS. THIS PROPOSAL IS RELEVANT TO THE MARS DATA ANALYSIS PROGRAM AS IT SEEKS TO UNDERTAKE WORK NECESSARY FOR THE ANALYSIS AND INTERPRETATION OF MARS SPACECRAFT MISSION DATA AND WILL HEAVILY USE MISSION DATA IN THE GENERATION OF IMPROVED UNDERSTANDING OF THE MARTIAN CLIMATE SYSTEM. IT WILL ALSO IMPROVE ATMOSPHERIC MODELS THAT FURTHER THE UNDERSTANDING AND FORECASTING OF ATMOSPHERIC CONDITIONS THAT AFFECT SAFE PASSAGE OF SPACECRAFT THROUGH THE ATMOSPHERE. COLUMN WATER VAPOR ABUNDANCES RETRIEVED FROM CRISM SPECTRA WILL BE ARCHIVED AT NASA'S PDS ATMOSPHERES NODE. MODEL OUTPUT FROM OUR MOST REALISTIC GLOBAL WATER CYCLE SIMULATION WILL BE ARCHIVED IN THE NEW PLANETARY ATMOSPHERES AND CLIMATE MODELING ARCHIVE NODE (PACMAN) HOSTED AT DATA.NASA.GOV. IN ADDITION THE VERSION OF PLANETWRF WHICH WITH THIS OUTPUT WAS PRODUCED WILL BE ARCHIVED AT NASA'S GITHUB REPOSITORY FOR COMPLETE TRACEABILITY.