Comparison of microwave and infrared measurements of Martian atmospheric temperatures: implications for short-term climate variability

Abstract

This paper presents the first comparison of simultaneous Viking infrared and ground-based microwave measurements of the Martian atmosphere. The data are examined in order to investigate a 15-20 K difference between microwave and Viking measurements of mid-level (10-40 km) air temperature. These data have been used by Clancy et al [1990] to suggest that the Martian atmosphere is generally cooler and clearer than observed during the Viking era. This study suggests that the 15-20 K difference, which is most apparent during the non-'dust-storm' seasons, is not a real temperature difference, but instead results from a disagreement between the measurment techniques. The existence of this isntrumental bias implies that the Martian climate has not substantially changed since the Viking era.