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MOTIVATION: ALTHOUGH URANUS DID NOT SHOW MUCH EVIDENCE OF CLOUDS DURING THE VOYAGER ERA (1986) WHEN THE PLANET APPROACHED ITS 2007 EQUINOX NUMEROUS CLOUD FEATURES POPPED UP INDICATIVE OF A DRAMATIC INCREASE IN DYNAMIC ACTIVITY. EVEN MORE SURPRISING WAS THE EXTREME CLOUD ACTIVITY OBSERVED IN 2014 SEVEN YEARS AFTER EQUINOX. THERE ARE A NUMBER OF STRIKING CLOUD FEATURES: I) LARGE CLOUDSTHAT LOOK LIKE GROUPS OF DISCRETE CLOUD FEATURES: SUCH CLOUDS HAVE BEEN SEEN ON BOTH HEMISPHERES SOMETIMES FOR MANY YEARS BEFORE THEY DISAPPEAR. SINCE THEY EXTEND OVER A FEW DEGREES IN LATITUDE ONE WOULD EXPECT THEM TO SHEAR APART; HOWEVER THEY DONT. THEY SOMETIMES ARE ACCOMPANIED BY A DARK SPOT; THIS AND THE APPARENT COHERENCE ARE SUGGESTIVE THAT VORTICES IN THE DEEPER ATMOSPHERE MAY BE RESPONSIBLE FOR THESE CLOUDS. II) POLAR FEATURES: WHEN VOYAGER 2 ARRIVED AT URANUS IN 1986 THE SOUTH POLE WAS FACING THE SUN AND A FEATURELESS BRIGHT SOUTH POLAR HAZE WAS SEEN AT HIGH LATITUDES. WHEN THE NORTH POLAR REGION CAME INTO VIEW NUMEROUS SMALL DISCRETE CLOUD FEATURES WERE OBSERVED. IN ADDITION TO THESE CLOUDS THE CONDENSABLE GASES (CH4 NH3 H2S) APPEAR TO BE DEPLETED OVER BOTH THE NORTH AND SOUTH POLAR REGIONS OF URANUS AS INDICATED BY HST/STIS AND MICROWAVE OBSERVATIONS. ALTHOUGH THE LATTER DATA ARE SUGGESTIVE OF SUBSIDING MOTIONS OVER THE POLES THIS SEEMS IN DIRECT CONTRAST TO THE NUMEROUS CLOUD FEATURES NEAR THE NORTH POLE. OUR AIM IN THIS PROPOSAL IS TO DETERMINE THE DYNAMICS IN URANUS ATMOSPHERE BOTH ON GLOBAL (GLOBAL CIRCULATION) AND LOCAL (VORTICES STORMS) SCALES.OBJECTIVES/METHODOLOGY: WE WILL USE THE UPGRADED VLA IN ITS MOST EXTENDED ARRAY TO PRODUCE MAPS OF THE PLANET THAT ARE RESOLVED IN BOTH LATITUDE AND LONGITUDE PROVIDING RESOLUTIONS ON SCALES AS SMALL AS 1500 KM OR ~30 IN LATITUDE/LONGITUDE AT DISK CENTER. WE WILL SIMULTANEOUSLY OBSERVE WITH HST AND KECK IN THE VISIBLE-NIR TO CHARACTERIZE THE CLOUDS. THE COMBINATION ENABLES US TO COUPLE CLOUD FORMATION TO GAS DYNAMICS AND CONDENSATION. SUCH DATA ARE CRITICAL FOR UNDERSTANDING THE GLOBAL CIRCULATION PATTERN LOCALIZED STORM SYSTEMS AND TURBULENT MOTIONS IN URANUS ATMOSPHERE. ALMA OBSERVATIONS WILL BE CONDUCTED TO PROBE THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE. SUCH DATA ARE CRITICAL FOR UNDERSTANDING THE GLOBAL CIRCULATION PATTERN LOCALIZED STORM SYSTEMS AND TURBULENT MOTIONS IN URANUS'S ATMOSPHERE.RELEVANCE: IN NASAS 2014 SCIENCE PLAN FOR 2013--2022 NASA'S SCIENCE VISION IS DESCRIBED AS: ASCERTAIN THE CONTENT ORIGIN AND EVOLUTION OF THE SOLAR SYSTEM AND THE POTENTIAL FOR LIFE ELSEWHERE WHICH HAS BEEN TRANSLATED INTO: TO EXPLORE AND OBSERVE THE OBJECTS IN THE SOLAR SYSTEM TO UNDERSTAND HOW THEY FORMED AND EVOLVED AND TO ADVANCE THE UNDERSTANDING OF HOW CHEMICAL AND PHYSICAL PROCESSES IN OUR SOLAR SYSTEM OPERATE INTERACT AND EVOLVE. IN THIS PROPOSAL WE INTEND TO STUDY URANUS USING GROUNDBASED OBSERVATIONS. THESE OBSERVATIONS ALONG WITH THEIR ANALYSIS CONFORM TO THE ABOVE VISION AND ARE IMPORTANT TO HELP PREPARE FOR FUTURE MISSIONS AND UNDERSTAND THE VOYAGER DATA IN TERMS OF SEASONAL CHANGES. THEY ALSO HELP UNDERSTAND EXOPLANETS AN IMPORTANT GOAL INNASAS ASTROPHYSICS DIVISION.

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Regents Of The University Of California, The

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MOTIVATION: ALTHOUGH URANUS DID NOT SHOW MUCH EVIDENCE OF CLOUDS DURING THE VOYAGER ERA (1986) WHEN THE PLANET APPROACHED ITS 2007 EQUINOX NUMEROUS CLOUD FEATURES POPPED UP INDICATIVE OF A DRAMATIC INCREASE IN DYNAMIC ACTIVITY. EVEN MORE SURPRISING WAS THE EXTREME CLOUD ACTIVITY OBSERVED IN 2014 SEVEN YEARS AFTER EQUINOX. THERE ARE A NUMBER OF STRIKING CLOUD FEATURES: I) LARGE CLOUDSTHAT LOOK LIKE GROUPS OF DISCRETE CLOUD FEATURES: SUCH CLOUDS HAVE BEEN SEEN ON BOTH HEMISPHERES SOMETIMES FOR MANY YEARS BEFORE THEY DISAPPEAR. SINCE THEY EXTEND OVER A FEW DEGREES IN LATITUDE ONE WOULD EXPECT THEM TO SHEAR APART; HOWEVER THEY DONT. THEY SOMETIMES ARE ACCOMPANIED BY A DARK SPOT; THIS AND THE APPARENT COHERENCE ARE SUGGESTIVE THAT VORTICES IN THE DEEPER ATMOSPHERE MAY BE RESPONSIBLE FOR THESE CLOUDS. II) POLAR FEATURES: WHEN VOYAGER 2 ARRIVED AT URANUS IN 1986 THE SOUTH POLE WAS FACING THE SUN AND A FEATURELESS BRIGHT SOUTH POLAR HAZE WAS SEEN AT HIGH LATITUDES. WHEN THE NORTH POLAR REGION CAME INTO VIEW NUMEROUS SMALL DISCRETE CLOUD FEATURES WERE OBSERVED. IN ADDITION TO THESE CLOUDS THE CONDENSABLE GASES (CH4 NH3 H2S) APPEAR TO BE DEPLETED OVER BOTH THE NORTH AND SOUTH POLAR REGIONS OF URANUS AS INDICATED BY HST/STIS AND MICROWAVE OBSERVATIONS. ALTHOUGH THE LATTER DATA ARE SUGGESTIVE OF SUBSIDING MOTIONS OVER THE POLES THIS SEEMS IN DIRECT CONTRAST TO THE NUMEROUS CLOUD FEATURES NEAR THE NORTH POLE. OUR AIM IN THIS PROPOSAL IS TO DETERMINE THE DYNAMICS IN URANUS ATMOSPHERE BOTH ON GLOBAL (GLOBAL CIRCULATION) AND LOCAL (VORTICES STORMS) SCALES.OBJECTIVES/METHODOLOGY: WE WILL USE THE UPGRADED VLA IN ITS MOST EXTENDED ARRAY TO PRODUCE MAPS OF THE PLANET THAT ARE RESOLVED IN BOTH LATITUDE AND LONGITUDE PROVIDING RESOLUTIONS ON SCALES AS SMALL AS 1500 KM OR ~30 IN LATITUDE/LONGITUDE AT DISK CENTER. WE WILL SIMULTANEOUSLY OBSERVE WITH HST AND KECK IN THE VISIBLE-NIR TO CHARACTERIZE THE CLOUDS. THE COMBINATION ENABLES US TO COUPLE CLOUD FORMATION TO GAS DYNAMICS AND CONDENSATION. SUCH DATA ARE CRITICAL FOR UNDERSTANDING THE GLOBAL CIRCULATION PATTERN LOCALIZED STORM SYSTEMS AND TURBULENT MOTIONS IN URANUS ATMOSPHERE. ALMA OBSERVATIONS WILL BE CONDUCTED TO PROBE THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE. SUCH DATA ARE CRITICAL FOR UNDERSTANDING THE GLOBAL CIRCULATION PATTERN LOCALIZED STORM SYSTEMS AND TURBULENT MOTIONS IN URANUS'S ATMOSPHERE.RELEVANCE: IN NASAS 2014 SCIENCE PLAN FOR 2013--2022 NASA'S SCIENCE VISION IS DESCRIBED AS: ASCERTAIN THE CONTENT ORIGIN AND EVOLUTION OF THE SOLAR SYSTEM AND THE POTENTIAL FOR LIFE ELSEWHERE WHICH HAS BEEN TRANSLATED INTO: TO EXPLORE AND OBSERVE THE OBJECTS IN THE SOLAR SYSTEM TO UNDERSTAND HOW THEY FORMED AND EVOLVED AND TO ADVANCE THE UNDERSTANDING OF HOW CHEMICAL AND PHYSICAL PROCESSES IN OUR SOLAR SYSTEM OPERATE INTERACT AND EVOLVE. IN THIS PROPOSAL WE INTEND TO STUDY URANUS USING GROUNDBASED OBSERVATIONS. THESE OBSERVATIONS ALONG WITH THEIR ANALYSIS CONFORM TO THE ABOVE VISION AND ARE IMPORTANT TO HELP PREPARE FOR FUTURE MISSIONS AND UNDERSTAND THE VOYAGER DATA IN TERMS OF SEASONAL CHANGES. THEY ALSO HELP UNDERSTAND EXOPLANETS AN IMPORTANT GOAL INNASAS ASTROPHYSICS DIVISION. · GrantIndex