The aim of this post is to separate the individual drainage basins from the mask containing all the glaciated regions on the ASTER image obtained in the previous post. It is not possible to do this in a total automatic procedure. However we will try to do it as much as possible. A Digital Elevation Model (DEM) of the area covered by the ASTER image is needed.

Step 1: Preparing data

This post is about my latest research published in the Journal of Geophysical Research about the GIA response over Antarctica. But let’s start from the beginning… What is GIA? For those who may not be familiar with the term (I wont blame you!), GIA stands for Glacial-Isostatic Adjustment. This is a response of the Earth’s mantle to changes in the surface. The Earth’s mantle is a viscoelastic material which responds very slowly to changes in the surface. For instance, after the last glaciation (~20.000 years ago), the large ice-sheets lying over northern Europe and north America melted away, causing a “rebound” (or an uplift trend) of the solid Earth, which, in fact, is still going on!. We can still feel these changes nowadays, but GIA is a really difficult process to be measured, specially in Antarctica!

Glaciers on the Southern Antarctic Peninsula have begun losing mass at a rapid and accelerating rate. A team of researchers, including myself, documented the dramatic thinning of the land-based ice, which began in 2009, using satellite altimetry and gravity observations. The melting and weakening of ice shelves reduce their buttressing effect, allowing the glaciers to flow more quickly to the sea

Today I came across this amazing initiative mapforenvironment.org, lying at the boundary between environmental activism and mapping geekness. Obviously I couldn’t be writing about anything else right now!

One of my favourite regions in the world is the Svalbard archipelago. It is situated in the Norwegian Arctic region, about midway between continental Norway and the North Pole. Yes, it is pretty high up! The largest island is Spitsbergen, where I had the chance to spent a couple of months studying in the northern-most university in the world! We did not have buses or cars for commuting, but we had snow-scooters instead! (i will leave anecdotes from this trip for another post)