The Neutral Atmosphere of Venus as Studied with the Mariner V Radio Occultation Experiments

Abstract

view Abstract Citations (359) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Neutral Atmosphere of Venus as Studied with the Mariner V Radio Occultation Experiments Fjeldbo, Gunnar ; Kliore, Arvydas J. ; Eshleman, Von R. Abstract The Mariner V radio occultation measurements at 423.3 and 2297 MHz (S band) are used to derive profiles in height of refractivity, molecular number density, pressure, temperature, and dispersive radio- frequency absorption for the atmosphere of Venus. The measurements cover heights between about 90 and 35 km (above a reference surface at a radius of 6050 km), over a pressure range from about 4X 10- to 7 atmospheres. Results obtained on the day and night sides are remarkably similar. The 90- to 60-km region contains inversion and thermal layers with the minimum temperature being at least as low as 180 0K. The average temperature lapse rate is 4 0K/km between 80 and 60 km. From 60 to 50 km the lapse rate is about 10 K/km, equal to the dry adiabatic rate for CO2. No radio absorption was observed above 50 km. In the 50- to 35-km height region, the lower-frequency signal was not absorbed, but the S-band signal suffered an approximately constant loss of 4X 10- dB per kilometer of propagation path. Assuming that the agent causing the microwave loss has negligible refractivity, there is a minimum in the temperature lapse rate between 50 and 45 km altitude. Below this transition region, the atmosphere may be slightly superadiabatic with the temperature reaching approximately 500 0K at the lowest level of measurement. The temperature and microwave loss profiles suggest the presence of two different cloud systems separated in altitude by about 10 km. Publication: The Astronomical Journal Pub Date: March 1971 DOI: 10.1086/111096 Bibcode: 1971AJ.....76..123F full text sources ADS |