AGU: Geophysical Research Letters

 

Editors' Highlight

First maps of nighttime clouds on Mars

In the season when Mars is the farthest away from the Sun, prominent water ice cloud belts form over the planet's tropics. Past simulations have highlighted the importance of water ice clouds to the Martian water cycle and suggest that the tropical cloud belt undergoes daily cyclical changes, with maximum opacity in the early morning hours. Noting that observations of water ice clouds on Mars have been limited to sunlit conditions, Wilson et al. (2007) mapped nighttime clouds by identifying their radiative influence on the seasonal evolution of surface brightness temperatures observed by the Thermal Emission Spectrometer instrument aboard the Mars Global Surveyor (MGS). They also provided spatial maps of atmospheric absorption derived from MGS's Mars Orbiter Laser Altimeter that corroborate their technique and show the insulating effect of these clouds. The authors discovered that the nighttime clouds are thicker and more extensive than daytime clouds. Their technique is the first to spatially map the nighttime clouds and provide an estimate of their thermal influence.

View abstract

View full article (Subscription required)