In this highly suggstive VIS image, taken by the NASA - Mars Odyssey Orbiter on November, 24th, 2015, and during its 61.858th orbit around the Red Planet, we can see a small part of the Martian, Northern Sub-Region knoen as Hyperboreae Undae: an extremely large Dunefield located between the North Polar Cap and Escorial Crater.
This image was taken during the Northern Spring and the Dunes, as you can see, still have (---> are covered by a) significant (amount of) Surface Frost. As you know, all the Dunes "darken", in a (relatively) short lap of time, as the Frost sublimates from (---> due to) Solar Heating and, as a consequence of such a phenomenon, the Dark Sands that form them and which were covered by the Frost, became (finally) visible.
Latitude (centered): 77,8284° North
Longitude (centered): 309,3880° East
This image (which is an Original Mars Odyssey Orbiter b/w and NON Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 20237) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.