Digital Geography

Observing deforestation with Sentinel-1

While preparing for an upcoming presentation at the annual meeting of the American Geophysical Union (AGU) I came across a topic that I thought might make an interesting blog post.  The presentation is about using data from the Sentinel-1 mission for Earth Science applications.  The Sentinel-1 spacecraft are C-band SAR systems launched and operated by the European Space Agency (ESA).  An innovative aspect of this mission is that the collection scenario devised by ESA is systematic and very broad in coverage.  Using Sentinel-1 we can monitor Earth using SAR data like never before.

Extracting information from Sentinel-1

SAR images can see through clouds and in darkness, and are therefore very useful for operational monitoring of our seas. Detecting ships, icebergs, wind patterns, and oil spills is daily business in Europe with the Sentinel-1 satellite. Want to see for yourself how to extract information from a SAR image? In this tutorial, we’ll use the SNAP toolbox for Sentinel-1 to extract information on the number of ships at sea.

First images from recently launched Sentinel 2 satellite

The earth observation satellite Sentinel-2 with Sentinel-2A and Sentinel 2B was launched on June 23rd 2015 from space centre Kourou in French Guiana. The mission is part of the Copernicus mission by ESA. The liftoff was recorded by ESA and can be watched here. Sentinel will be a complement to the multispectral satellites of the Landsat mission and SPOT. All observation systems in combination reveal a higher temporal resolution by shifted orbits and large stripe widths (Sentinel: 290km). Sentinel has a repetition rate of 10 days, Landsat 8 of 16 days but in combination with Landsat 7 a 8 day…

A great visualization of InSAR data by the ESA – ups and downs at the East African Rift

InSAR (Interferometric Synthetic Aperture Radar) is one of the greatest remote sensing tools for everyone interested in crustal movements. The principle is simple: A satellite equipped with a radar device is constantly measuring the topography of the Earth while orbiting. When it crosses the same area a second time, the two datasets can be compared and the changes in altitude can be measured. The fascinating thing is that these changes may be as small as < 1 cm, using the interferometric effect! Repeated measurements allow creating time series and monitoring areas with crustal deformation. Such deformation can be caused by…