Mars's Thermal Environment

extracted from Thermal Environments JPL D-8160

The following table summarizes the range of Direct Solar, Reflected Solar (Albedo), and Planetary Infrared for the planet Mars.


                 Perihelion       Aphelion         Mean

----------------------------------------------------------------

Direct Solar       717 W/sqM      493 W/sqM        589 W/sqM

Albedo             0.29           0.29             0.29
(subsolar peak)

Planetary IR.      
  near subsolar    470 W/sqM      315 W/sqM        390 W/sqM
  polar caps        30 W/sqM       30 W/sqM         30 W/sqM

The Martian planetary infrared has been derived from Mariner and Viking Orbiter spacecraft data.

The distribution of Martian albedo with latitude is shown below. This albedo shows a shift in spectrum to the red in comparison with other planets and peaks at 0.7micron (versus 0.47micron for the Earth).

It should be pointed out that the above environments assumes no dust storms. The presence of global dust storms would slightly increase the overall albedo (dark area albedos would increase more than bright area albedos). The increase atmosphere opacity would dampen the effective diurnal temperature range making the IR more benign.

                  ALBEDO DISTRIBUTION

   Latitude       Maximum ALbedo       Minimum ALbedo
-------------------------------------------------------
   80 to 90            0.5                  0.3
   70 to 80            0.5                  0.2
   60 to 70            0.5                  0.2
   50 to 60            0.5                  0.17
   40 to 50            0.28                 0.17
   30 to 40            0.28                 0.18
   20 to 30            0.28                 0.22
   10 to 20            0.28                 0.25
    0 to 10            0.28                 0.25
  -10 ro 0             0.28                 0.20
  -20 to -10           0.25                 0.18
  -30 to -20           0.22                 0.18
  -40 to -30           0.22                 0.18
  -50 to -40           0.40                 0.25
  -60 to -50           0.40                 0.25
  -70 to -60           0.40                 0.30
  -80 to -70           0.40                 0.40
  -90 to -80           0.40                 0.40

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