Coordinated Hubble Space Telescope and Venus Express Observations of Venus upper cloud deck.

Transcription

1 Coordinated Hubble Space Telescope and Venus Express Observations of Venus upper cloud deck. Kandis Lea Jessup 1, Emmanuel Marcq 2, Franklin Mills 3, Arnaud Mahieux 4, Brad Sandor 5, Sanjay Limaye 6, Mark Allen 7, Jean -Loup Bertaux 2, Wojtek Markiewicz 8, Tony Roman 9, Ann-Carine Vandaele 4, Valerie Wilquet 4, Colin Wilson 10, Yuk Yung 7 Southwest Research Institute, Boulder CO LATMOS 2 Research School of Physical Sciences and Engineering, The Australian National University, Canberra, ACT Belgian Institute for Space Aeronomy 4 Space Science Institute 5 University of Wisconsin 6 Caltech 7 Max Planck Institute 8 Space Science Telescope Institute 9 Oxford 10 1

2 2 DEC JAN JAN OBS 3 OBS 2 : 15S, L65 DEC 28 : 32S, L65 DEC 28 OBS 2: 45S, L145 JAN 22 OBS 3: 65S, L145 JAN 22 : 45S, L160 JAN 27 : 65S, L160 JAN 27 * SOIR * * * SOIR

3 3 HST/STIS G230LB 0.1 long slit spectrum of Venus WAVELENGTH (A) DEC JAN JAN OBS 3 OBS 2 : 15S, L65 DEC 28 : 32S, L65 DEC 28 OBS 2: 45S, L145 JAN 22 OBS 3: 65S, L145 JAN 22 : 45S, L160 JAN 27 : 65S, L160 JAN 27

4 4 DEC JAN JAN OBS 3 OBS 2 : 15S, L65 DEC 28 : 32S, L65 DEC 28 OBS 2: 45S, L145 JAN 22 OBS 3: 65S, L145 JAN 22 : 45S, L160 JAN 27 : 65S, L160 JAN 27

5 DEC JAN JAN OBS 3 OBS 2 : 15S, L65 DEC 28 : 32S, L65 DEC 28 OBS 2: 45S, L145 JAN 22 OBS 3: 65S, L145 JAN 22 SZA 0-70 VMC : 45S, L160 JAN 27 : 65S, L160 JAN 27 SZA evening quadrant morning quadrant DECEMBER 28,2010 JANUARY 27,2011

6 JANUARY 27 DECEMBER 28

7 7 Median, std low-latitude daily dayside average ppbv UV HST RESULT SUMMARY Low-latitude average ppbv value between SZA 0-60 Median, std SZA low-latitude average ppbv value SZA SO 2 SO SO 2 SO SO 2 SO SO 2 SO 43±35 3.9± ±96 8.5± Note, dayside average means averaging all values detected between 0-60 SZA, per day; all the values listed are derived based on the column density fit above 75 km, for the low-latitude region found between ±28 latitude VMR values determined based on VIRA 1985 CO 2 profile SO 2 ppbv range observed between 0-60 SZA 12/28/ ppbv 3-9 ppbv 01/22/ ppbv 1-3 ppbv 01/27/ ppbv ppbv SO ppbv range observed between 0-60 SZA DEC JAN JAN OBS 3 OBS 2 : 15S, L65 DEC 28 : 32S, L65 DEC 28 OBS 2: 45S, L145 JAN 22 OBS 3: 65S, L145 JAN 22 : 45S, L160 JAN 27 : 65S, L160 JAN 27

8 ALTITUDE BEHAVIOR CONSISTENT WITH COINCIDENT OBSERVATIONS AND PHOTOCHEMICAL PREDICTIONS Sandor et al JCMT 2011 HST Fig X_6.3 The SO 2/ SO (right) abundance ratios derived from the HST UV and JCMT sub-mm observations in the 75±2 and km altitude ranges, respectively, are compared to the ratio values predicted by several photochemical models. The km SO 2 /SO profile inferred from the combination of these observations is reasonably consistent with the Mills et al. predictions for the dayside SO 2 /SO gas abundance ratio. 8

9 CONSISTENCY OF LATITUDE/LOCAL TIME BEHAVIOR WITH PHOTOCHEMICAL PREDICTIONS UNDER INVESTIGATION

10 CONCLUSIONS Trends in HST observation consistent with long standing trend of rapid variation in SO 2 gas density with latitude Switch in latitudinal gradient, 5 days after decrease in SO2 gas density consistent with trends derived from averaging long term SPICAV observations HST and Venus Express observations provide first detailed look at variation in SO2 gas density with local time SO2 gas density near morning terminator ~ 2x > than dayside average Exploratory photochemical modeling reliant on SOx and Chlorine chemistry also predicts enhancement in SO2 density near the terminator of same order of magnitude as observed by HST, suggesting Differences between dayside and near terminator gas densities imply that comparison between datasets needs to be carefully done, and that comparison of data taken at diverse local times/inconsistent field of view is suspect

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12 DECEMBER 28,2010

13 ALTITUDE BEHAVIOR CONSISTENT WITH PHOTOCHEMICAL PREDICTIONS Sandor et al JCMT 2011 HST Fig X_6.3 The SO 2/ SO (right) abundance ratios derived from the HST UV and JCMT sub-mm observations in the 75±2 and km altitude ranges, respectively, are compared to the ratio values predicted by several photochemical models. The km SO 2 /SO profile inferred from the combination of these observations is reasonably consistent with the Mills et al. predictions for the dayside SO 2 /SO gas abundance ratio. 13