OVERVIEW: DUNES ARE THE MOST VISIBLE AND WIDESPREAD SOURCE OF INFORMATION ABOUT SURFACE-ALTERING WINDS ON MARS. THE HIRISE WEB SITE LISTS 4341 DUNE IMAGES AND THE MARS GLOBAL DIGITAL DUNE DATABASE LISTS 547 DUNE FIELDS COVERING AN AREA OF 70 000 KM2. MANY PREVIOUS STUDIES HAVE USED DUNE MORPHOLOGY TO INTERPRET WIND REGIMES ON MARS (GOOGLE SCHOLAR REPORTS 237 PUBLICATIONS WITH THE WORDS MARS AND DUNES IN THE TITLE). DESPITE THIS CONSIDERABLE PREVIOUS WORK INTERPRETATIONS OF MARS DUNES HAS BEEN RESTRICTED TO RELATIVELY SIMPLE WIND REGIMES: (A) 1 OR 2 WIND DIRECTIONAL MODES; (B) PRIOR TO 2014 THERE WAS NO KNOWLEDGE OF DUNES IN THE FINGER MODE (THAT ORIGINATES ON BEDS PARTIALLY STARVED OF SAND AS IS COMMON ON MARS); AND (C) ALTHOUGH COHESIVENESS IS KNOWN TO BE IMPORTANT IN CONTROLLING DUNE MORPHOLOGY AND ORIENTATION THERE HAVE BEEN NO SYSTEMATIC STUDIES OF THIS CONTROL FOR A WIDE RANGE OF WIND REGIMES. THE PROPOSED WORK IS THE ONLY WAY WE KNOW OF TO INTERPRET WIND REGIMES FOR THESE DIVERSE CATEGORIES OF DUNE-FORMING REGIMES. GOALS: THE OBJECTIVES OF THIS PROPOSED STUDY ARE TO INTERPRET WIND REGIMES USING TWO NEW APPROACHES THAT INCORPORATE RECENT DISCOVERIES OF DUNE DYNAMICS. APPROXIMATELY 85% OF THE REQUESTED FUNDING WILL SUPPORT DATA ANALYSIS OF HIRISE IMAGES WITH THE REMAINING 15% GOING TOWARD NON-ANALYSIS COMPUTATIONAL TASKS NECESSARY FOR INTERPRETATIONS AND COMPUTATIONAL TASKS THAT WILL ENHANCE FUTURE INTERPRETATIONS. METHODS: WE PROPOSE TO USE AN EXISTING CELLULAR AUTOMATON MODEL (EXTENSIVELY TESTED AND PREVIOUSLY USED FOR DUNE SIMULATIONS) TO MODEL THE ORIENTATION AND MORPHOLOGY OF DUNES CREATED BY 3600 WIND REGIMES ON BEDS WITH FULL AND PARTIAL COVERAGE WITH BOTH NON-COHESIVE AND COHESIVE/SAND. WE WILL THEN APPLY RESULTS TO 25 DUNE FIELDS ON MARS WITH PRIORITY GIVEN TO DUNE FIELDS NEAR PROPOSED LANDING SITES. THE APPROACHES PROPOSED HERE OFFER SUBSTANTIAL ADVANTAGES OVER ALL OTHER APPROACHES: (1) THEY CAN INTERPRET TRI-DIRECTIONAL WIND REGIMES THAT ARE NECESSARY TO PRODUCE CERTAIN MORPHOLOGIES (PING ET AL. 2017); (2) THEY CAN QUANTIFY DISPERSION IN INDIVIDUAL WIND MODES (NARTEAU ET AL. 2017); AND (3) THE COMPUTATIONAL APPROACH IS MORE BROADLY APPLICABLE THAN FENTON AT AL. S (2014A B) APPLICATION OF RUBIN AND HUNTER S (1987) MAXIMUM GROSS BEDFORM-NORMAL RULE. THE PROPOSED METHODS ARE IDEALLY SUITED FOR MARS BECAUSE THE GAS LATTICE CELLULAR AUTOMATON MODEL IS APPLICABLE TO ANY VALUES OF GRAVITY AND ATMOSPHERIC DENSITY. MOREOVER THE RESULTS DEPEND ONLY ON THE RELATIVE PROPORTIONS OF SAND TRANSPORT FROM THE SPECIFIED DIRECTIONS REGARDLESS OF WHETHER THE SAND IS TRANSPORTED BY REPTATION SALTATION OR RIPPLE MIGRATION AND REGARDLESS OF ANY HYSTERESIS IN SAND TRANSPORT. RELEVANCE: HIRISE HAS COLLECTED THOUSANDS OF IMAGES OF DUNES AND AS DETAILED IN THE PROPOSAL NO OTHER APPROACH CAN INTERPRET WIND REGIMES AS ACCURATELY QUANTITATIVELY IN AS MUCH DETAIL OR WITH SUCH BROAD APPLICATION. THE RESULTS ARE IMPORTANT NOT ONLY FOR SCIENTIFIC UNDERSTANDING BUT ALSO FOR MARS SURFACE ACTIVITIES SUCH AS DRIVING (ARVIDSON ET AL. 2016) AND DESIGN OF STRUCTURES. RESEARCHER QUALIFICATIONS: THE INVESTIGATORS HAVE HAD SUBSTANTIAL EXPERIENCE WORKING ON DUNES. THE PI HAS WORKED FOR 4 DECADES ON DUNES AND HAS WRITTEN A BOOK COMPUTER CODE A WEB SITE THAT IS USED WORLD-WIDE FOR RESEARCH A DVD AND MORE THAN TWO-DOZEN JOURNAL PAPERS ON DUNES IN MODERN AND ANCIENT DESERTS ON EARTH MARS AND TITAN. NARTEAU'S NUMERICAL MODEL HAS PRODUCED INNOVATIVE RESULTS PUBLISHED IN NUMEROUS PUBLICATIONS AND OLIVIER ROZIER IS AN EXPERT IN STREAMLINING CODE. SYLVAIN COURRECH DU PONT DEVELOPED THE WORLD'S MOST SOPHISTICATED MULTI-DIRECTIONAL FLOW LAB APPARATUS AND HE DISCOVERED THE "FINGER-MODE INSTABILITY" OF DUNES. CONCLUSION: NO OTHER APPROACH OFFERS THE POSSIBILITY OF EXTRACTING SO MUCH INFORMATION FROM DUNES OBSERVED IN HIRISE IMAGES AN IMPORTANT GOAL THAT IS RELEVANT TO MARS DATA ANALYSIS.