Five Martian Years Of Msl Gale Crater Cloud Opacity
Measurements: Determining A Scattering Phase Function
For The Aphelion Cloud Belt
C. W. Hayes1 (Hayes954@Yorku.Ca), J. L. Kloos2, C. L. Campbell1, A. C. Innanen1, H. M. Sapers1, And J. E.
Moores1. 1centre For Research In Earth And Space Sciences, York University, Toronto, On, Canada; 2department
Of Astronomy, University Of Maryland, College Park, Md, Usa.
Introduction:
The Martian Climate Is Dominated By The Seasonal
Effects Of The Planet’S High Orbital Eccentricity
(~0.0935), Which Takes It ~20% Closer To The Sun At
Perihelion Than At Aphelion. This Difference Results In
Significant Variations In Solar Insolation And Thus Atmospheric Conditions Over The Course Of The Martian
Year. Two Martian Seasons Can Thus Be Defined: The
Dusty Season, Which Occurs Around Perihelion (Ls =
135° - 360°) And Is Characterized By Higher Temperatures And Increased Atmospheric Dust Loading; And The
Cloudy Season, Which Occurs Around Aphelion (Ls = 0°
- 135°) And Is Characterized By The Formation Of The
Aphelion Cloud Belt (Acb), A Water-Ice Cloud Feature
That Surrounds The Planet At Latitudes Between 10°S
And 30°N (Wolff Et Al., 1999).