Sulfuric acid vapor and sulfur dioxide in the atmosphere of Venus as observed by the Venus Express radio science experiment VeRa

Icarus ◽  
2021 ◽  
Vol 362 ◽  
pp. 114405
Author(s):  
J. Oschlisniok ◽  
B. Häusler ◽  
M. Pätzold ◽  
S. Tellmann ◽  
M.K. Bird ◽  
...  
2021 ◽  
Author(s):  
Janusz Oschlisniok ◽  
Bernd Häusler ◽  
Martin Pätzold ◽  
Silvia Tellmann ◽  
Michael Bird

<p>The main cloud deck within Venus' atmosphere, which covers the entire planet between approx. 50 and 70 km altitude, is believed to consist mostly of liquid sulfuric acid. The temperature below the main clouds is high enough to evaporate the H2SO4 droplets into gaseous sulfuric acid forming a haze layer which extends to altitudes as deep as 35 km. Gaseous sulfuric acid in Venus’ lower atmosphere is responsible for a strong absorption of radio waves as seen in Mariner, Pioneer Venus, Magellan and Venera radio science observations. Radio wave absorption measurements can be used to derive the amount of H2SO4 in Venus’ atmosphere. The radio science experiment VeRa onboard Venus Express probed the atmosphere of Venus between 2006 and 2014 with radio signals at 13 cm (S-band) and 3.6 cm (X-band) wavelengths. The orbit of the Venus Express spacecraft allowed to sound the atmosphere over a wide range of latitudes and local times providing a global picture of the sulfuric acid vapor distribution. We present the global H2SO4(g) distribution derived from the X-band radio signal attenuation for the time of the entire Venus Express mission. The observation is compared with results obtained from a 2-D transport model. The VeRa observations were additionally used to estimate the abundance of SO2 near the cloud bottom. The global distribution of SO2 at these altitudes is presented and compared with results obtained from other experiments. Eight years of VEX observation allow to study the long-term evolution of H2SO4 and SO2. The latter is presented for the northern polar region.</p>


2020 ◽  
Author(s):  
Janusz Oschlisniok ◽  
Bernd Häusler ◽  
Martin Pätzold ◽  
Silvia Tellmann ◽  
Michael Bird

<p>The main Venus clouds, covering the entire planet between approx. 50 and 70 km altitude, are believed to consist mostly of liquid sulfuric acid. Below the clouds, the temperature is high enough to evaporate those droplets into gaseous sulfuric acid forming a haze layer which extends to altitudes as deep as 35 km. H<sub>2</sub>SO<sub>4</sub>(g) is the main absorber of radio waves as was observed in Mariner, Pioneer Venus, Magellan and Venera radio occultation measurements. Radio wave absorption measurements can be used to derive the amount of H<sub>2</sub>SO<sub>4</sub> as well as to estimate upper limits of SO<sub>2</sub> in Venus’ atmosphere. The radio science experiment VeRa onboard Venus Express probed the atmosphere of Venus between 2006 and 2014 with radio signals at 13 cm (S-band) and 3.6 cm (X-band) wavelengths. Thanks to the orbit of VEX, a wide range of latitudes and local times was covered so that a global picture of the H<sub>2</sub>SO<sub>4</sub>(g) ditribution was obtained. We present H<sub>2</sub>SO<sub>4</sub>(g) profiles as well as upper limits of sulfur dioxide near the cloud base derived from the X-band radio signal from the entire Venus Express mission. More than 600 H<sub>2</sub>SO<sub>4</sub>(g) profiles show the global sulfuric acid vapor distribution covering the northern and southern hemisphere on the day- and night side of the planet. A distinct latitudinal H<sub>2</sub>SO<sub>4</sub>(g) and SO<sub>2</sub> variation and a southern northern symmetry are clearly visible. Observations over 8 years allow to study also long-term variations. Indications for temporal H<sub>2</sub>SO<sub>4</sub>(g) and SO<sub>2</sub> variations are found, at least at northern polar latitudes. The results shall be compared with observations retrieved by other experiments onboard Venus Express. Additionally, the observed H<sub>2</sub>SO<sub>4</sub>(g) distribution will be compared with results obtained from a mass transport model.</p>


Icarus ◽  
2012 ◽  
Vol 221 (2) ◽  
pp. 940-948 ◽  
Author(s):  
J. Oschlisniok ◽  
B. Häusler ◽  
M. Pätzold ◽  
G.L. Tyler ◽  
M.K. Bird ◽  
...  

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