Mars' northern polar regions in transition
MARS DAILY by Staff Writers
Paris (ESA) Aug 08, 2011
A newly released image from ESA's Mars Express shows the north pole of Mars during the red planet's summer solstice. All the carbon dioxide ice has gone, leaving just a bright cap of water ice.
|Detailed images at ESA|
This image was captured by the orbiter's High-Resolution Stereo Camera on 17 May 2010 and shows part of the northern polar region of Mars during the summer solstice. The solstice is the longest day and the beginning of the summer for the planet's northern hemisphere.
The ice shield is covered by frozen water and carbon dioxide ice in winter and spring but by this point in the martian year all of the carbon dioxide ice has warmed and evaporated into the planet's atmosphere.
Only water ice is left behind, which shows up as bright white areas in this picture. From these layers, large bursts of water vapour are occasionally released into the atmosphere.
The polar ice follows the seasons. In winter, part of the atmosphere recondenses as frost and snow on the northern cap. These seasonal deposits can extend as far south as 45 degrees N latitude and be up to a metre thick.
Another phenomenon occurs on the curved scarps of the northern polar cap, such as the Rupes Tenuis slope. During spring, the seasonal carbon dioxide layer is covered by water frost. At certain times, winds remove the the millimetre-thick top layer of frozen water, revealing the carbon dioxide ice below.
These processes bear witness to a dynamic water cycle on Mars and may lead to the varying accumulation of water ice over the polar cap.
Other noticeable features include the Chasma Boreale canyon, coloured deposits and a large dune field.
Chasma Boreale is about 2 km deep, 580 km long and about 100 km wide. Its walls allow a perfect view into the strata within the deposits. There are impact craters on the canyon floor, some heavily covered by sand and some partly exhumed.
Dark and light-toned deposits can be seen as a fine and regular covering. The darker sediments have been dropped by the winds during spring dust storms. The patterns are created when the deposits change in quantity according to the seasons.
The polar cap is surrounded by a large dune field, parts of which extend 600 km to the south.
Mars Express will soon be using its radar to probe the northern polar cap in three dimensions. Since the radar antenna was deployed in mid-2005, the team have been waiting for the right conditions to observe the region.
The radar works best at night when the electrical interference from the planet's atmosphere is at a minimum. An excellent opportunity to observe the cap's shape, depth and composition occurs in August and September 2011.
The opinion of climate realists/skeptics is that (1) the Earth's 20th century climate warmed in the thirties and forties, cooled in the fifties and sixties, and warmed in the seventies and eighties; (2) the changes were due to natural, very possibly solar influences.ReplyDelete
Has any credible scientist examined photographic records of Mars to see if the same pattern appeared in its ice caps?
I think satellite photos would be necessary, esp. to distinguish between melting of CO2 ice and H2O ice, only available over past couple decades.ReplyDelete
Geeze we must be really hotting up down here on earth...LOLReplyDelete
One comment. I was wondering if the ice caps on Mars would start growing again given that the Sun appears to have started to quite down.ReplyDelete
"I think satellite photos would be necessary, esp. to distinguish between melting of CO2 ice and H2O ice, only available over past couple decades. "ReplyDelete
Why? Either the visible icecap varies with the variations on Earth or they don't. That's the test I suggest.
After computation of the astronomical Milankovitch cycles on deep sea cores for the last 2.4 Ma the same cycles revealed to exist in land sediment series: Long Term (last 2.4 Ma, Pleistocene) and Middle Term (last 127Ka, Last Interglacial - Last Glacial Time-span) Time Series after cycle computation with the newly developed ExSpect method. Moreover, the same calculation method proved useful for Short Term Time Series as well on sediments of the last 10.000 years (10Ka). The latter cycles as those obtained for ice and glacial lake deposits on Mars could also clearly be traced back in the planetary correlations computed by the NASA Goddard Space Flight Center. This points to an extra terrestrial astronomical forcing of the origin of all these cycles on both planets Earth and Mars.ReplyDelete
Here's a high res picture of the layers of the South Polar deposits.
Good work, papertiger!ReplyDelete
I got it from John Cook.ReplyDelete
"Global warming on Mars, ice caps melting".
Well, it was a comment I made at John Cook's blog back in 2007.ReplyDelete
Bless his heart for not deleting it.
Can't remember where I found it the first time.
I don't bother to try to post at his blog anymore after he deleted 3 of my comments.ReplyDelete
Yeah he thinks he's a big hairy deal now.ReplyDelete
It's probably just luck, and catching him early, that my posts got through.
Good news is I'm a perpetual thorn in his side. Ouch.
please keep it up! Thanks!ReplyDelete
This argument is part of a greater one that other planets are warming. If this is happening throughout the solar system, clearly it must be the sun causing the rise in temperatures – including here on Earth.
It is curious that the theory depends so much on sparse information – what we know about the climates on other planets and their history – yet its proponents resolutely ignore the most compelling evidence against the notion. Over the last fifty years, the sun’s output has decreased slightly: it is radiating less heat. We can measure the various activities of the sun pretty accurately from here on Earth, or from orbit above it, so it is hard to ignore the discrepancy between the facts and the sceptical argument that the sun is causing the rise in temperatures.
Is it any wonder that I'm confused?