Hemispheric distributions of HCl above and below the Venus’ clouds by ground-based 1.7μm spectroscopy

Iwagami, N.; Ohtsuki, Shoko; Tokuda, Kazuki; Ohira, N.; Kasaba, Yasumasa; Imamura, Takeshi; Sagawa, Hideo; Hashimoto, George L.; Takeuchi, Satoru; Ueno, Munetaka; Okumura, Shin-ichiro

doi:10.1016/j.pss.2008.05.009

Cited by 47 publications

(30 citation statements)

References 27 publications

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“…The cloud height is close (within a few kilometers) to the reference in the low latitudes between ±30°, and it becomes lower by about 10 km than the reference at ±70°. This is similar to the pre- vious report using the 1.7 lm region (Iwagami et al, 2008), but a little steeper in the middle latitudes. According to the 8.6 lm measurements by Venera 15 (Zasova et al, 1993), the cloud is lower at high latitudes than at low latitudes by a few kilometers; this is similar to the present results although the height change they found occurs at around ±50°.…”

Section: Discussionsupporting

confidence: 90%

“…To estimate the CO mixing ratio at each data point (about 500 points per each scan after the 3 Â 3 co-adding), the following procedure including two steps is applied for each points as in the same way as Iwagami et al (2008): (1) the height deviation of the cloud structure from the reference cloud ( Fig. 5) is estimated by changing the cloud height so as to obtain the same equivalent widths for the measured and calculated CO 2 R12 lines as in the similar way as Ignatiev et al (2009), and (2) the mixing ratio of CO is estimated by changing the CO mixing ratio using the height deviation found in step (1) so as to obtain the same equivalent widths for the measured and calculated CO lines.…”

Section: Discussionmentioning

confidence: 99%

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Hemispherical distribution of CO above the Venus’ clouds by ground-based 2.3μm spectroscopy

Iwagami

Yamaji

Ohtsuki

et al. 2010

Icarus

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Hemispherical distribution of CO above the Venus’ clouds by ground-based 2.3μm spectroscopy

Iwagami

Yamaji

Ohtsuki

et al. 2010

Icarus

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“…Since the 0.90-µm region is in a window for CO 2 absorption, variation of the CO 2 column abundance above the cloud does not greatly affect the calculated brightness. This variation of ±4 km in the Venus cloud altitude may actually be present (see, for example, Iwagami et al, 2008;Ignatiev et al, 2009). A similar procedure is performed by changing the atmospheric temperature, which reveals that changes in temperature scarcely even affect brightness: a ±10 K increase in temperature causes only a ±0.02% change in brightness.…”

Section: Resultsmentioning

confidence: 95%

Contrast sources for the infrared images taken by the Venus mission AKATSUKI

Takagi

Iwagami

2011

Earth Planet Sp

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A feasibility study has been carried out to look for the source of contrast that will be seen in the infrared images of Venus taken by the cameras on board AKATSUKI. This procedure used a cloud model based on the measurements of previous entry probes and radiative transfer calculations. The source of the small contrast expected in the 0.90-µm dayside image was found to be due to inhomogeneity in the cloud optical thickness, with the variations in cloud altitude and temperature having little effect. The source of the large contrast expected in the 2.26-µm nightside image was also found to be due to inhomogeneity in the cloud optical thickness. We attempted to determine the representative altitude of the cloud layers, but this could not be specified to one particular layer. The brightness expected in the 2.02-µm dayside image was found to be affected by the cloud altitude, as expected since the 2.02-µm is in a moderate CO 2 absorption band; however, it is also affected by the cloud optical thickness. The brightness expected in the 10-µm image was found to be affected mostly by temperature; however, the effects due to cloud optical thickness and cloud altitude are also important. It is necessary to use all of the information obtained at various wavelengths to gain a correct understanding of the brightness distribution of the Venus images taken by AKATSUKI.

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“…Here we adopt the average value of X H2O = 30 ppm. We considered 14 water buffers given by Lewis (1970), Fegley & Treiman (1992), and (Bertaux et al 2007) to 0.74 ppm at an altitude of 60-66 km (Iwagami et al 2008) and 0.40 ppm at 12 -24 km (Iwagami et al 2008). Krasnopolsky (2010) found an HCl abundance of 0.40 ppm at 74 km.…”

Section: Venus Surface-atmosphere Equilibrium Modelmentioning

confidence: 99%

Atmospheric Chemistry of Venus-Like Exoplanets

Schaefer

Fegley

2011

ApJ

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Abstract:We use thermodynamic calculations to model atmospheric chemistry on terrestrial exoplanets that are hot enough for chemical equilibria between the atmosphere and lithosphere, as on Venus. The results of our calculations place constraints on abundances of spectroscopically observable gases, the surface temperature and pressure, and the mineralogy of the planetary surface. These results will be useful in planning future observations of the atmospheres of terrestrial-sized exoplanets by current and proposed space observatories such as the Hubble Space Telescope (HST), Spitzer, James Webb Space Telescope (JWST), and Darwin.

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Hemispheric distributions of HCl above and below the Venus’ clouds by ground-based 1.7μm spectroscopy

Cited by 47 publications

References 27 publications

Hemispherical distribution of CO above the Venus’ clouds by ground-based 2.3μm spectroscopy

Hemispherical distribution of CO above the Venus’ clouds by ground-based 2.3μm spectroscopy

Contrast sources for the infrared images taken by the Venus mission AKATSUKI

Atmospheric Chemistry of Venus-Like Exoplanets

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