Net global thermal emission from the Venusian atmosphere
Abstract
Improved calculations of net emission from the northern hemisphere of Venus are presented. These are based on temperature profiles, water vapor mixing ratio profiles, and cloud models retrieved in 120 solar-fixed latitude-longitude bins from infrared measurements in six spectral channels made over a period of 72 days by the orbiter infrared radiometer (OIR) instrument of the Pioneer Venus mission. Only carbon dioxide, sulfuric acid cloud, and water vapor are considered as significant sources of atmospheric opacity, and the role of the latter component is found to be minor. The sensitivity of the calculations to extreme alternative cloud models, measurement errors, and calibration errors is also discussed. Net emission is found to be only weakly dependent on latitude and longitude during the period of observation with the exception of the high-latitude polar collar region, where emission is low. Mean net emission from the northern hemisphere is 157.0 ± 6.9 W.m -2, corresponding to an equivalent temperature of 229.4 ± 2.5°K. If this figure is characteristic of the whole planet and if thermal balance is assumed, the bolometric albedo of Venus is 0.762 ± 0.011. This value is consistent with the latest estimates within experimental error.
- Publication:
-
Icarus
- Pub Date:
- November 1982
- DOI:
- 10.1016/0019-1035(82)90111-7
- Bibcode:
- 1982Icar...52..245S
- Keywords:
-
- Atmospheric Radiation;
- Infrared Radiometers;
- Opacity;
- Thermal Emission;
- Venus Atmosphere;
- Venus Clouds;
- Albedo;
- Atmospheric Optics;
- Carbon Dioxide;
- Cloud Physics;
- Water Vapor