3 THE GOAL OF THIS PROPOSAL IS TO INVESTIGATE THE PROCESSES ON TITAN CONTROLLING (1) THE ATMOSPHERIC CIRCULATION, (2) THE METHANE CYCLE, AND (3) THE ACTION OF WIND AT THE SURFACE. THEORETICAL, ANALYTICAL OR SIMPLIFIED (E.G. 2D) MODELS PROVIDE A POWERFUL MEANS OF INVESTIGATING SPECIFIC PHENOMENA IN TITAN'S ATMOSPHERE, AND ENABLE HYPOTHESES TO BE FORMED CONCERNING THE RELEVANT MECHANISMS AT WORK. HOWEVER, REAL ATMOSPHERES ARE COMPLICATED BY THREE-DIMENSIONAL PROCESSES, NON-LINEAR INTERACTIONS, AND NUMEROUS FEEDBACKS. THREE-DIMENSIONAL GENERAL CIRCULATION MODELS (GCMS) PROVIDE AN INTEGRATED FRAMEWORK FOR CAPTURING THE LINEAR AND NON-LINEAR INTERACTIONS OF A WIDE RANGE OF PROCESSES, AND ARE THUS REQUIRED TO TEST AND FURTHER DEVELOP HYPOTHESES, TO STUDY THE COMPLETE ATMOSPHERIC SYSTEM, AND TO SIMULATE (AND EVENTUALLY PREDICT) ALL ASPECTS OF THE TIME-VARYING 3D ATMOSPHERE. DESPITE THEIR USEFULNESS, HOWEVER, GCMS (AND PARTICULARLY PLANETARY GCMS) CONTAIN MANY UNKNOWN OR POORLY KNOWN ASSUMPTIONS AND PARAMETERS. A TITAN GCM THEREFORE CANNOT HOPE TO PROPERLY REPRESENT ITS INTENDED ATMOSPHERE UNTIL IT HAS BEEN CONFRONTED WITH SUFFICIENT OBSERVATIONS TO CONSTRAIN THESE PROPERLY, AND IT CAN SIMULTANEOUSLY (BY WHICH WE MEAN WITHIN A SINGLE SIMULATION) MATCH MULTI-INSTRUMENT OBSERVATIONS OF DISPARATE VARIABLES AND FEATURES. IN THIS WORK WE PROPOSE TO CONSTRAIN OUR EXISTING THREE-DIMENSIONAL GCM TITANWRF IN THE THREE AREAS DESCRIBED ABOVE. FOR (1) WE WILL DEVELOP AN OBSERVATION SYSTEM SIMULATION EXPERIMENT FOR THE CASSINI CIRS INSTRUMENT, USING IT TO COMPARE CIRS RADIANCES WITH TITANWRF PREDICTIONS, AND TO ASSESS WHETHER OBSERVATIONS SUPPORT THE EXISTENCE AND NATURE OF THE WAVE DRIVEN ANGULAR MOMENTUM TRANSFER EVENTS THAT ARE KEY TO PRODUCING STRATOSPHERIC SUPERROTATION IN TITANWRF. FOR (2) WE WILL ADD NEW PARAMETERIZATIONS OF METHANE CYCLE PROCESSES (INCLUDING MOIST CONVECTION AND SUB-SURFACE DIFFUSION) AND VARY TITANWRF'S PHYSICAL PARAMETERS, WITH THE AIM OF PRODUCING THE BEST MATCH TO THE OBSERVED METHANE CYCLE. FOR (3) WE WILL USE REALISTIC TOPOGRAPHY TO PREDICT GLOBAL AND MESOSCALE DUNE CHARACTERISTICS BASED ON THE LONG-TERM WIND FIELD, PROVIDING AN INDIRECT BUT RIGOROUS MEANS OF TESTING THE NEAR-SURFACE ATMOSPHERIC CIRCULATION PREDICTED BY TITANWRF, CONSTRAINING THE FACTORS THAT INFLUENCE WINDS (FROM SURFACE BOUNDARY CONDITIONS TO PHYSICAL PROCESSES), AND INVESTIGATING MECHANISMS BEHIND THE OBSERVED CHARACTERISTICS OF TITAN'S DUNES. AS WE REQUIRE TITANWRF TO SIMULTANEOUSLY MATCH OBSERVATIONS IN ALL THREE AREAS, RESULTS OF EACH INVESTIGATION WILL GUIDE WORK IN THE OTHERS, AND OUTPUT FROM OUR EVENTUAL `MOST REALISTIC' GCM ENCAPSULATING OUR BEST UNDERSTANDING OF TITAN WILL BE MADE PUBLICLY AVAILABLE VIA THE PLANETARY DATA SYSTEM (PDS) FOR WIDER COMMUNITY USE. Funding Only Action ($5k) 11/7/17 Not listed THE GOAL OF THIS PROPOSAL IS TO INVESTIGATE THE PROCESSES ON TITAN CONTROLLING (1) THE ATMOSPHERIC CIRCULATION (2) THE METHANE CYCLE AND (3) THE ACTION OF WIND AT THE SURFACE. THEORETICAL ANALYTICAL OR SIMPLIFIED (E.G. 2D) MODELS PROVIDE A POWERFUL MEANS OF INVESTIGATING SPECIFIC PHENOMENA IN TITAN'S ATMOSPHERE AND ENABLE HYPOTHESES TO BE FORMED CONCERNING THE RELEVANT MECHANISMS AT WORK.HOWEVER REAL ATMOSPHERES ARE COMPLICATED BY THREE-DIMENSIONAL PROCESSES NON-LINEAR INTERACTIONS AND NUMEROUS FEEDBACKS. THREE-DIMENSIONAL GENERAL CIRCULATION MODELS (GCMS) PROVIDE AN INTEGRATED FRAMEWORK FOR CAPTURING THE LINEAR AND NON-LINEAR INTERACTIONS OF A WIDE RANGE OF PROCESSES AND ARE THUS REQUIRED TO TEST AND FURTHER DEVELOP HYPOTHESES TO STUDY THE COMPLETE ATMOSPHERIC SYSTEM AND TO SIMULATE (AND EVENTUALLY PREDICT) ALL ASPECTS OF THE TIME-VARYING 3D ATMOSPHERE. DESPITE THEIR USEFULNESS HOWEVER GCMS (AND PARTICULARLY PLANETARY GCMS) CONTAIN MANY UNKNOWN OR POORLY KNOWN ASSUMPTIONSAND PARAMETERS. A TITAN GCM THEREFORE CANNOT HOPE TO PROPERLY REPRESENT ITS INTENDED ATMOSPHERE UNTIL IT HAS BEEN CONFRONTED WITH SUFFICIENT OBSERVATIONS TO CONSTRAIN THESE PROPERLY AND IT CAN SIMULTANEOUSLY (BY WHICH WE MEAN WITHIN A SINGLE SIMULATION) MATCH MULTI-INSTRUMENT OBSERVATIONS OF DISPARATE VARIABLES AND FEATURES. IN THIS WORK WE PROPOSE TO CONSTRAIN OUR EXISTING THREE-DIMENSIONALGCM TITANWRF IN THE THREE AREAS DESCRIBED ABOVE. FOR (1) WE WILL DEVELOP AN OBSERVATION SYSTEM SIMULATION EXPERIMENT FOR THE CASSINI CIRS INSTRUMENT USING IT TO COMPARE CIRS RADIANCES WITH TITANWRF PREDICTIONS AND TO ASSESS WHETHER OBSERVATIONS SUPPORT THE EXISTENCE AND NATURE OF THE WAVE DRIVEN ANGULAR MOMENTUM TRANSFER EVENTS THAT ARE KEY TO PRODUCING STRATOSPHERIC SUPERROTATION IN TITANWRF. FOR (2) WE WILL ADD NEW PARAMETERIZATIONS OF METHANE CYCLE PROCESSES (INCLUDING MOIST CONVECTION AND SUB-SURFACE DIFFUSION) AND VARY TITANWRF'S PHYSICAL PARAMETERS WITH THE AIM OF PRODUCING THE BEST MATCH TO THE OBSERVED METHANE CYCLE. FOR (3) WE WILL USE REALISTIC TOPOGRAPHY TO PREDICT GLOBAL AND MESOSCALE DUNE CHARACTERISTICS BASED ON THE LONG-TERM WIND FIELD PROVIDING AN INDIRECT BUT RIGOROUS MEANS OF TESTING THE NEAR-SURFACE ATMOSPHERIC CIRCULATION PREDICTED BY TITANWRF CONSTRAINING THE FACTORS THAT INFLUENCE WINDS (FROM SURFACE BOUNDARY CONDITIONS TO PHYSICAL PROCESSES) AND INVESTIGATING MECHANISMS BEHIND THE OBSERVED CHARACTERISTICS OF TITAN'S DUNES. AS WE REQUIRE TITANWRF TO SIMULTANEOUSLY MATCH OBSERVATIONS IN ALL THREE AREAS RESULTS OF EACH INVESTIGATION WILL GUIDE WORK IN THE OTHERS AND OUTPUT FROM OUR EVENTUAL `MOST REALISTIC' GCM ENCAPSULATING OUR BEST UNDERSTANDING OF TITAN WILL BE MADE PUBLICLY AVAILABLE VIA THE PLANETARY DATA SYSTEM (PDS) FOR WIDER COMMUNITY USE. ($5k) 11/7/17 Not listed THE GOAL OF THIS PROPOSAL IS TO INVESTIGATE THE PROCESSES ON TITAN CONTROLLING (1) THE ATMOSPHERIC CIRCULATION (2) THE METHANE CYCLE AND (3) THE ACTION OF WIND AT THE SURFACE. THEORETICAL ANALYTICAL OR SIMPLIFIED (E.G. 2D) MODELS PROVIDE A POWERFUL MEANS OF INVESTIGATING SPECIFIC PHENOMENA IN TITAN'S ATMOSPHERE AND ENABLE HYPOTHESES TO BE FORMED CONCERNING THE RELEVANT MECHANISMS AT WORK.HOWEVER REAL ATMOSPHERES ARE COMPLICATED BY THREE-DIMENSIONAL PROCESSES NON-LINEAR INTERACTIONS AND NUMEROUS FEEDBACKS. THREE-DIMENSIONAL GENERAL CIRCULATION MODELS (GCMS) PROVIDE AN INTEGRATED FRAMEWORK FOR CAPTURING THE LINEAR AND NON-LINEAR INTERACTIONS OF A WIDE RANGE OF PROCESSES AND ARE THUS REQUIRED TO TEST AND FURTHER DEVELOP HYPOTHESES TO STUDY THE COMPLETE ATMOSPHERIC SYSTEM AND TO SIMULATE (AND EVENTUALLY PREDICT) ALL ASPECTS OF THE TIME-VARYING 3D ATMOSPHERE. DESPITE THEIR USEFULNESS HOWEVER GCMS (AND PARTICULARLY PLANETARY GCMS) CONTAIN MANY UNKNOWN OR POORLY KNOWN ASSUMPTIONSAND PARAMETERS. A TITAN GCM THEREFORE CANNOT HOPE TO PROPERLY REPRESENT ITS INTENDED ATMOSPHERE UNTIL IT HAS BEEN CONFRONTED WITH SUFFICIENT OBSERVATIONS TO CONSTRAIN THESE PROPERLY AND IT CAN SIMULTANEOUSLY (BY WHICH WE MEAN WITHIN A SINGLE SIMULATION) MATCH MULTI-INSTRUMENT OBSERVATIONS OF DISPARATE VARIABLES AND FEATURES. IN THIS WORK WE PROPOSE TO CONSTRAIN OUR EXISTING THREE-DIMENSIONALGCM TITANWRF IN THE THREE AREAS DESCRIBED ABOVE. FOR (1) WE WILL DEVELOP AN OBSERVATION SYSTEM SIMULATION EXPERIMENT FOR THE CASSINI CIRS INSTRUMENT USING IT TO COMPARE CIRS RADIANCES WITH TITANWRF PREDICTIONS AND TO ASSESS WHETHER OBSERVATIONS SUPPORT THE EXISTENCE AND NATURE OF THE WAVE DRIVEN ANGULAR MOMENTUM TRANSFER EVENTS THAT ARE KEY TO PRODUCING STRATOSPHERIC SUPERROTATION IN TITANWRF. FOR (2) WE WILL ADD NEW PARAMETERIZATIONS OF METHANE CYCLE PROCESSES (INCLUDING MOIST CONVECTION AND SUB-SURFACE DIFFUSION) AND VARY TITANWRF'S PHYSICAL PARAMETERS WITH THE AIM OF PRODUCING THE BEST MATCH TO THE OBSERVED METHANE CYCLE. FOR (3) WE WILL USE REALISTIC TOPOGRAPHY TO PREDICT GLOBAL AND MESOSCALE DUNE CHARACTERISTICS BASED ON THE LONG-TERM WIND FIELD PROVIDING AN INDIRECT BUT RIGOROUS MEANS OF TESTING THE NEAR-SURFACE ATMOSPHERIC CIRCULATION PREDICTED BY TITANWRF CONSTRAINING THE FACTORS THAT INFLUENCE WINDS (FROM SURFACE BOUNDARY CONDITIONS TO PHYSICAL PROCESSES) AND INVESTIGATING MECHANISMS BEHIND THE OBSERVED CHARACTERISTICS OF TITAN'S DUNES. AS WE REQUIRE TITANWRF TO SIMULTANEOUSLY MATCH OBSERVATIONS IN ALL THREE AREAS RESULTS OF EACH INVESTIGATION WILL GUIDE WORK IN THE OTHERS AND OUTPUT FROM OUR EVENTUAL `MOST REALISTIC' GCM ENCAPSULATING OUR BEST UNDERSTANDING OF TITAN WILL BE MADE PUBLICLY AVAILABLE VIA THE PLANETARY DATA SYSTEM (PDS) FOR WIDER COMMUNITY USE. $0 6/12/17 2 THE GOAL OF THIS PROPOSAL IS TO INVESTIGATE THE PROCESSES ON TITAN CONTROLLING (1) THE ATMOSPHERIC CIRCULATION, (2) THE METHANE CYCLE, AND (3) THE ACTION OF WIND AT THE SURFACE. THEORETICAL, ANALYTICAL OR SIMPLIFIED (E.G. 2D) MODELS PROVIDE A POWERFUL MEANS OF INVESTIGATING SPECIFIC PHENOMENA IN TITAN'S ATMOSPHERE, AND ENABLE HYPOTHESES TO BE FORMED CONCERNING THE RELEVANT MECHANISMS AT WORK. HOWEVER, REAL ATMOSPHERES ARE COMPLICATED BY THREE-DIMENSIONAL PROCESSES, NON-LINEAR INTERACTIONS, AND NUMEROUS FEEDBACKS. THREE-DIMENSIONAL GENERAL CIRCULATION MODELS (GCMS) PROVIDE AN INTEGRATED FRAMEWORK FOR CAPTURING THE LINEAR AND NON-LINEAR INTERACTIONS OF A WIDE RANGE OF PROCESSES, AND ARE THUS REQUIRED TO TEST AND FURTHER DEVELOP HYPOTHESES, TO STUDY THE COMPLETE ATMOSPHERIC SYSTEM, AND TO SIMULATE (AND EVENTUALLY PREDICT) ALL ASPECTS OF THE TIME-VARYING 3D ATMOSPHERE. DESPITE THEIR USEFULNESS, HOWEVER, GCMS (AND PARTICULARLY PLANETARY GCMS) CONTAIN MANY UNKNOWN OR POORLY KNOWN ASSUMPTIONS AND PARAMETERS. A TITAN GCM THEREFORE CANNOT HOPE TO PROPERLY REPRESENT ITS INTENDED ATMOSPHERE UNTIL IT HAS BEEN CONFRONTED WITH SUFFICIENT OBSERVATIONS TO CONSTRAIN THESE PROPERLY, AND IT CAN SIMULTANEOUSLY (BY WHICH WE MEAN WITHIN A SINGLE SIMULATION) MATCH MULTI-INSTRUMENT OBSERVATIONS OF DISPARATE VARIABLES AND FEATURES. IN THIS WORK WE PROPOSE TO CONSTRAIN OUR EXISTING THREE-DIMENSIONAL GCM TITANWRF IN THE THREE AREAS DESCRIBED ABOVE. FOR (1) WE WILL DEVELOP AN OBSERVATION SYSTEM SIMULATION EXPERIMENT FOR THE CASSINI CIRS INSTRUMENT, USING IT TO COMPARE CIRS RADIANCES WITH TITANWRF PREDICTIONS, AND TO ASSESS WHETHER OBSERVATIONS SUPPORT THE EXISTENCE AND NATURE OF THE WAVE DRIVEN ANGULAR MOMENTUM TRANSFER EVENTS THAT ARE KEY TO PRODUCING STRATOSPHERIC SUPERROTATION IN TITANWRF. FOR (2) WE WILL ADD NEW PARAMETERIZATIONS OF METHANE CYCLE PROCESSES (INCLUDING MOIST CONVECTION AND SUB-SURFACE DIFFUSION) AND VARY TITANWRF'S PHYSICAL PARAMETERS, WITH THE AIM OF PRODUCING THE BEST MATCH TO THE OBSERVED METHANE CYCLE. FOR (3) WE WILL USE REALISTIC TOPOGRAPHY TO PREDICT GLOBAL AND MESOSCALE DUNE CHARACTERISTICS BASED ON THE LONG-TERM WIND FIELD, PROVIDING AN INDIRECT BUT RIGOROUS MEANS OF TESTING THE NEAR-SURFACE ATMOSPHERIC CIRCULATION PREDICTED BY TITANWRF, CONSTRAINING THE FACTORS THAT INFLUENCE WINDS (FROM SURFACE BOUNDARY CONDITIONS TO PHYSICAL PROCESSES), AND INVESTIGATING MECHANISMS BEHIND THE OBSERVED CHARACTERISTICS OF TITAN'S DUNES. AS WE REQUIRE TITANWRF TO SIMULTANEOUSLY MATCH OBSERVATIONS IN ALL THREE AREAS, RESULTS OF EACH INVESTIGATION WILL GUIDE WORK IN THE OTHERS, AND OUTPUT FROM OUR EVENTUAL `MOST REALISTIC' GCM ENCAPSULATING OUR BEST UNDERSTANDING OF TITAN WILL BE MADE PUBLICLY AVAILABLE VIA THE PLANETARY DATA SYSTEM (PDS) FOR WIDER COMMUNITY USE. Funding Only Action $0 6/12/17 1 THE GOAL OF THIS PROPOSAL IS TO INVESTIGATE THE PROCESSES ON TITAN CONTROLLING (1) THE ATMOSPHERIC CIRCULATION, (2) THE METHANE CYCLE, AND (3) THE ACTION OF WIND AT THE SURFACE. THEORETICAL, ANALYTICAL OR SIMPLIFIED (E.G. 2D) MODELS PROVIDE A POWERFUL MEANS OF INVESTIGATING SPECIFIC PHENOMENA IN TITAN'S ATMOSPHERE, AND ENABLE HYPOTHESES TO BE FORMED CONCERNING THE RELEVANT MECHANISMS AT WORK. HOWEVER, REAL ATMOSPHERES ARE COMPLICATED BY THREE-DIMENSIONAL PROCESSES, NON-LINEAR INTERACTIONS, AND NUMEROUS FEEDBACKS. THREE-DIMENSIONAL GENERAL CIRCULATION MODELS (GCMS) PROVIDE AN INTEGRATED FRAMEWORK FOR CAPTURING THE LINEAR AND NON-LINEAR INTERACTIONS OF A WIDE RANGE OF PROCESSES, AND ARE THUS REQUIRED TO TEST AND FURTHER DEVELOP HYPOTHESES, TO STUDY THE COMPLETE ATMOSPHERIC SYSTEM, AND TO SIMULATE (AND EVENTUALLY PREDICT) ALL ASPECTS OF THE TIME-VARYING 3D ATMOSPHERE. DESPITE THEIR USEFULNESS, HOWEVER, GCMS (AND PARTICULARLY PLANETARY GCMS) CONTAIN MANY UNKNOWN OR POORLY KNOWN ASSUMPTIONS AND PARAMETERS. A TITAN GCM THEREFORE CANNOT HOPE TO PROPERLY REPRESENT ITS INTENDED ATMOSPHERE UNTIL IT HAS BEEN CONFRONTED WITH SUFFICIENT OBSERVATIONS TO CONSTRAIN THESE PROPERLY, AND IT CAN SIMULTANEOUSLY (BY WHICH WE MEAN WITHIN A SINGLE SIMULATION) MATCH MULTI-INSTRUMENT OBSERVATIONS OF DISPARATE VARIABLES AND FEATURES. IN THIS WORK WE PROPOSE TO CONSTRAIN OUR EXISTING THREE-DIMENSIONAL GCM TITANWRF IN THE THREE AREAS DESCRIBED ABOVE. FOR (1) WE WILL DEVELOP AN OBSERVATION SYSTEM SIMULATION EXPERIMENT FOR THE CASSINI CIRS INSTRUMENT, USING IT TO COMPARE CIRS RADIANCES WITH TITANWRF PREDICTIONS, AND TO ASSESS WHETHER OBSERVATIONS SUPPORT THE EXISTENCE AND NATURE OF THE WAVE DRIVEN ANGULAR MOMENTUM TRANSFER EVENTS THAT ARE KEY TO PRODUCING STRATOSPHERIC SUPERROTATION IN TITANWRF. FOR (2) WE WILL ADD NEW PARAMETERIZATIONS OF METHANE CYCLE PROCESSES (INCLUDING MOIST CONVECTION AND SUB-SURFACE DIFFUSION) AND VARY TITANWRF'S PHYSICAL PARAMETERS, WITH THE AIM OF PRODUCING THE BEST MATCH TO THE OBSERVED METHANE CYCLE. FOR (3) WE WILL USE REALISTIC TOPOGRAPHY TO PREDICT GLOBAL AND MESOSCALE DUNE CHARACTERISTICS BASED ON THE LONG-TERM WIND FIELD, PROVIDING AN INDIRECT BUT RIGOROUS MEANS OF TESTING THE NEAR-SURFACE ATMOSPHERIC CIRCULATION PREDICTED BY TITANWRF, CONSTRAINING THE FACTORS THAT INFLUENCE WINDS (FROM SURFACE BOUNDARY CONDITIONS TO PHYSICAL PROCESSES), AND INVESTIGATING MECHANISMS BEHIND THE OBSERVED CHARACTERISTICS OF TITAN'S DUNES. AS WE REQUIRE TITANWRF TO SIMULTANEOUSLY MATCH OBSERVATIONS IN ALL THREE AREAS, RESULTS OF EACH INVESTIGATION WILL GUIDE WORK IN THE OTHERS, AND OUTPUT FROM OUR EVENTUAL `MOST REALISTIC' GCM ENCAPSULATING OUR BEST UNDERSTANDING OF TITAN WILL BE MADE PUBLICLY AVAILABLE VIA THE PLANETARY DATA SYSTEM (PDS) FOR WIDER COMMUNITY USE. Funding Only Action $136.6k 7/25/16