Thermal structure of Venus׳ nightside mesosphere as observed by infrared heterodyne spectroscopy at 10 μm

Evaluation of a method to retrieve temperature and wind velocity profiles of the Venusian nightside mesosphere from mid-infrared CO2 absorption line observed by heterodyne spectroscopy

“…Figure 17 compares our results to the temperature profiles shown in Fig. 7 of Stangier et al (2015) and to the previously obtained results in order to validate our retrieval tool. Figure 17a compares the retrieved temperature profiles at 33SLT3 with the values retrieved by Stangier et al (2015).…”

“…7 of Stangier et al (2015) and to the previously obtained results in order to validate our retrieval tool. Figure 17a compares the retrieved temperature profiles at 33SLT3 with the values retrieved by Stangier et al (2015). The values derived from VEX Radio Science (VeRa) radio occultation measurements at 33.8° S and 3:49 LT on 20 May 2012 (Stangier, 2015) are also shown in Fig.…”

“…CO 2 LTE absorption lines can be directly detected at altitudes of 60-90 km on the nightside by mid-infrared heterodyne spectroscopy. Stangier et al (2015) retrieved temperature profiles with the instrument named Heterodyne Instrument for Planetary Wind and Composition (HIPWAC;Kostiuk et al 2005) attached to the Cassegrain focus of the National Aeronautics and Space Administration (NASA) Infrared Telescope Facility (IRTF) 3-m telescope. Nakagawa et al (2016) also demonstrated the possibility of the wind velocity retrieval with an accuracy of 15-25 m/s for altitudes of 85-95 km.…”

“…This work follows Stangier et al (2015) and Nakagawa et al (2016), and presents a new attempt to retrieve Doppler wind velocity as well as temperature profile in the Venusian nightside from the CO 2 absorption line resolved by mid-infrared heterodyne spectroscopy. The target sensitivity of the Doppler wind velocity retrieval aims to constrain the vertical transition of RSZ wind at altitudes below 100 km.…”

“…Finally, we apply the method to the Venusian nightside spectra observed by a midinfrared heterodyne spectrometer HIPWAC attached to IRTF on May 19-22, 2012. The data were reselected and reprocessed from the dataset analyzed by Stangier et al (2015). We validate our scheme by comparing with both retrieved temperature profiles.…”