dunes

August 13, 2018

Where dunes once trod

Mars has been dusty, and that’s affecting the quality of HiRISE images (just look at the recent images in the catalog and you’ll see they’re not that great). That’s made it hard for me to choose a good one for […]
July 16, 2018

Spring is a messy time

In many areas on Earth that get winter snow, spring thaw is a messy time. Frozen ground turns to mud, and there may be runoff everywhere from melting snow and spring rain. Or if you live in a place that […]
July 8, 2018

Field of barchans

It’s July, and I’ve had a busy summer so far. This is my first post in a few weeks – I’ve been out at various meetings, and last week I spent with my family on vacation. The one week of […]
May 30, 2018

The Mars Global Digital Dune Database

There are a lot of dune fields on Mars. Over the last ten years I’ve been part of a group that’s mapped out the big dark dunes on the planet to see where they form, and to understand the sedimentary […]
May 9, 2018

Entourage

Here’s a grand dune, making its stately way northward under winds blowing mainly from the south-southeast (bottom to top), with a secondary wind blowing from the southwest (lower left to upper right). There are two rippled and sharp-crested slip faces […]
March 5, 2018

“Baby” dunes on Mars are big

Baby dunes on Mars are pretty big compared to those on Earth. In this 885×512 m (0.55×0.32 mi) frame, there are four dunes of roughly the same size, all of which are about as small as dunes can get on […]
March 1, 2018

Dune trails

There’s so much going on in this 0.75×0.75 km (0.47×0.47 mi) image. You’re looking at a broad dune migrating toward the upper right. It’s early summer, but this is close enough to the north pole that some winter ice lingers […]
February 20, 2018

Ius Chasma dunes: they move

Many dunes on Mars are actively migrating, like these dunes (view is 0.4×0.5 km, 0.25×0.31 mi). These are found deep in Ius Chasma, one of the Valles Marineris. These dunes slowly migrate toward the right, pushed by winds blowing from […]
February 12, 2018

Where dune fields begin

This is the upwind edge of a dune field (825×625 m, 0.51×0.39 mi). Winds blow down a cliff (offscreen) from the lower right, blowing sand toward the upper left. Elongated dunes have formed parallel to the resultant wind direction, only […]