LtE in CMO #247

From  Terrence Z MARTIN

@. . . . . From: Terry Z. Martin <>

To: <>; <>; <>; <>

Cc: <>; <>

Sent: Friday, July 06, 2001 8:48 AM

Subject: Mars dust storm report


The recent Martian dust storm occurred at a great time for terrestrial observation, and that is how I first heard of it - the reports from Japanese observers. Excellent work, and some fine pictures!


 The thermal signature of the storm in the Mars Global Surveyor horizon sensor data (15 micrometers wavelength in the infrared; this is a bulk measurement of the atmospheric temperature, which rises as sunlight heat the dust) appears to develop along with the visual evidence of bright yellow clouds. I made a series of thermal maps, one per day, and they show a gradual warming in the northern Hellas region starting about day of year 175 (June 24). The attachment is a Quicktime movie of the days 175-181. The data come from daytime hours only (0600 to 1800 hrs local time). I use west longitudes.


23 June 2001













24 June 2001













25 June 2001














26 June 2001













28 June 2001














30 June 2001











I would not expect the temperature to track the visual appearance of the dust storms exactly. What I am seeing is the heating due to dust that is mixed to considerable height in the atmosphere (many km). The behavior of the 1999 Ls 225 warming showed strong control by an existing thermal wave pattern rather than matching the dust storms seen in the MOC (MGS camera) image data.

  The warming grows strongly after day 179, and begins to show up in the northern mid-latitudes on day 180. The warming moves eastward in both the north and south after that. I will continue this movie as more data are processed. Because of this storm's early start within the dust storm season, it is particularly interesting.


(6 July 2001 email)


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