Analysis of Warm Nighttime Surface Temperature Anomalies in Gale Crater as a Potential Signature of Nighttime Clouds
Abstract
Mars Science Laboratory (MSL) has been continuously observing the micrometeorology within Gale crater since 2012 using the Rover Environmental Monitoring Station (REMS). This work explores the potential role of clouds in moderating the surface temperature within the crater, particularly in the nighttime. During the aphelion season when Mars is farthest from the Sun and the atmosphere is least dusty, a slight increase is observed in the daily minimum nighttime temperature. When we would expect the atmosphere to have its lowest temperatures around aphelion, the observed minimum daily nighttime temperature within Gale is slightly greater than it is in the time periods directly adjacent to aphelion. We contend that this is due to the formation of nighttime clouds which absorb outgoing radiation from the surface, re-radiating heat in the atmosphere and reducing surface cooling.
MSL has observed clouds regularly at Gale through daytime photometric observations, and it's well understood that their frequency and optical thicknesses reach a maximum around aphelion, but characterizing these clouds at night poses more of a challenge. We are unable to directly observe clouds in nighttime photometry outside of twilight, so their presence has to be inferred through other means, and this slight increase in the minimum nighttime temperatures could be one method. This hypothesis is strengthened by the recent photometric observations of noctilucent clouds in our season of interest for this current Mars Year. We will expand this investigation by working to determine the timing of cloud growth and decay throughout the night by looking at the hourly temperatures plotted over the aphelion season; the working hypothesis is that at some point during the night, a perturbation in the trend of these curves should be observed that is indicative of cloud formation.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P41B3417D
- Keywords:
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- 0343 Planetary atmospheres;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 6225 Mars;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 5405 Atmospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS;
- 5445 Meteorology;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS