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DescriptionSeasonal processes in the Northern polar dunes with Flow Like Features.gif |
English: Time differences between the images are 22 days and 12 days. The final picture shows a long feature that formed new between the two images, and its length is 60 meters so it grew at a rate of at least 5 meters per day.
[1]
The features progress through a sequence of changes, first wind blown, and then seepage features associated with the dune spots, and then finally, dark seepage features appear all along the dune crest as in this sequence. These images show the final stage, growth of the seepage features all along the dune crest. [1] These features form at a surface temperature of -90°C, and increase at between 0.3 meters and 7 meters a day. Proposed models for the features in this hemisphere predict liquid brines even in these low temperatures. [2] [1] Shortwave solar radiation can efficiently penetrate the translucent surface layer. This raises the temperature of the underlying surface and the dark ejecta, and the models predict that the temperatures can be raised high enough to melt the ice, which could then form brines on ice / salt interfaces. [3] An alternative mechanism for the Northern hemisphere involves dry ice and sand cascading down the slope but most of the models involve cold liquid brines. [2] I created this animation myself by combining the following HiRise images from NASA/JPL/University of Arizona, all taken in 2008:
PSP_007758_2575 - 22 March (2:06 PM) , sol 101 PSP_007903_2575 - 3rd April (2:07 PM), sol 113 (found the sols using the Earth date to Martian solar longtitude converter) |
Date | |
Source | http://www.uahirise.org/PSP_007903_2575 |
Author | NASA/JPL/University of Arizona |
Public domainPublic domainfalsefalse |
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This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.) | ![]() |
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Warnings:
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Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 13:59, 20 April 2015 |
![]() | 848 × 816 (1.86 MB) | Robertinventor | User created page with UploadWizard |
Original file (848 × 816 pixels, file size: 1.86 MB, MIME type: image/gif, looped, 3 frames, 2.4 s)
![]() | This is a file from the
Wikimedia Commons. Information from its
description page there is shown below. Commons is a freely licensed media file repository. You can help. |
DescriptionSeasonal processes in the Northern polar dunes with Flow Like Features.gif |
English: Time differences between the images are 22 days and 12 days. The final picture shows a long feature that formed new between the two images, and its length is 60 meters so it grew at a rate of at least 5 meters per day.
[1]
The features progress through a sequence of changes, first wind blown, and then seepage features associated with the dune spots, and then finally, dark seepage features appear all along the dune crest as in this sequence. These images show the final stage, growth of the seepage features all along the dune crest. [1] These features form at a surface temperature of -90°C, and increase at between 0.3 meters and 7 meters a day. Proposed models for the features in this hemisphere predict liquid brines even in these low temperatures. [2] [1] Shortwave solar radiation can efficiently penetrate the translucent surface layer. This raises the temperature of the underlying surface and the dark ejecta, and the models predict that the temperatures can be raised high enough to melt the ice, which could then form brines on ice / salt interfaces. [3] An alternative mechanism for the Northern hemisphere involves dry ice and sand cascading down the slope but most of the models involve cold liquid brines. [2] I created this animation myself by combining the following HiRise images from NASA/JPL/University of Arizona, all taken in 2008:
PSP_007758_2575 - 22 March (2:06 PM) , sol 101 PSP_007903_2575 - 3rd April (2:07 PM), sol 113 (found the sols using the Earth date to Martian solar longtitude converter) |
Date | |
Source | http://www.uahirise.org/PSP_007903_2575 |
Author | NASA/JPL/University of Arizona |
Public domainPublic domainfalsefalse |
![]() |
This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.) | ![]() |
![]() |
Warnings:
|
Click on a date/time to view the file as it appeared at that time.
Date/Time | Thumbnail | Dimensions | User | Comment | |
---|---|---|---|---|---|
current | 13:59, 20 April 2015 |
![]() | 848 × 816 (1.86 MB) | Robertinventor | User created page with UploadWizard |