webindia123.com June 9, 2016
Mosaic of Martian North Pole and Ice Cap from MOM
The Mars Colour Camera (MCC) on-board the Mars Orbiter Mission (MOM) has captured many images of North Pole of Mars.
The Indian Space Research Organisation (ISRO) ina release in its website said topographically corrected MCC reflectance mosaic was prepared by Space Applications Centre (SAC), ISRO, Ahmedabad using nine MCC images observed during December 16, 2015 to January 26, 2016.
The period of observation corresponds to the solar longitude (Ls) from 82 Deg to 100 Deg of 33rd Martian year.To keep the track of time on Mars, the position of Mars in its orbit around the Sun is used--it is a kind of longitudinal system that goes from 0 to 360 degrees.
Therefore solar longitudes (Ls) is used to keep track of the seasons on Mars; the Ls=0 Deg is the start of northern spring and Ls=180 Deg is the start of southern spring, the release said. The individual images were converted to atmosphere reflectance (I/F) and then, Minnaert topographic correction was applied.
The image shown was projected into Sample Azimuthal Equal Area, the resulting pieces were mosaicked for full view of the polar cap. The seasonal Martian polar caps wax and wane in response to the condensation and sublimation of carbon dioxide (CO2) resulting from seasonal insolation changes on Mars. It said in northern winters (Ls=270-360 Deg), the polar cap grows much larger in area since atmospheric CO2 freezes and deposits a layer of dry ice (frozen CO2) on top of the ice cap and the surrounding terrain. When summer returns (Ls=90-180 Deg), warm temperatures cause the dry ice to sublimate away, and the polar cap shrinks in size.
The period of North Pole observation from MCC belongs to the end of northern spring and early summers, showing seasonal sublimation. The northern ice cap on Mars extends about 1,100 km from pole. Major topographic and surface albedo features were easily seen in this mosaic, the release said. The edge of the ice cap was surrounded by "polar layered terrain", a series of layers of ice and dust.
The ground throughout the Polar Regions appears to have lots of ice in or under the soil. Winds caused by temperature differences between the ice cap and its surrounding, blow throughout the Polar Regions. ''They carve interesting grooves into the ice cap, and build up sand dunes in areas around the pole. Light brown areas are a mix of ice and dust and are called "polar layered terrain'', it said. The Dark brown areas around the ice cap were sand dunes. The huge canyon, Chasma Boreale was seen in the ice cap on the left side of the picture.UNI GV MVR 1500