Sep 24

A Golden Age for Earth Observation

By Sara Aparicio ( European Space Agency-ESA )
We are in the edge of an exciting new era for Earth observation (a.k.a.monitoring Earth from space), and anyone can be part of it. Last April, I had the pleasure of holding a series of demonstrations on exploiting large scalesatellite data from Copernicus, the largest single Earth observation programme in the world — and the most ambitious to date. These demonstrations, made on behalf of European Space Agency (ESA) and Earth Engine, took place during the European Geosciences Union (EGU) General Assembly 2017 in Vienna, Austria.

Copernicus data is produced by satellite missions called the ‘Sentinels’, aiming to autonomously and accurately provide global coverage of the Earth. Each mission (composed at least by 2 satellites) has different sensors on-board and capabilities. Sentinel-1 (all weather radar mission) and Sentinel-2(high-resolution optical mission) have six and five day repeat cycles at the Equator, respectively. The revisit frequency increases greatly at higher latitudes since orbit track spacing vary with latitude, increasing overlap near the poles.

Copernicus, the largest single Earth Observation programme in the world — and the most ambitious to date.

These satellites (along with Sentinel-3 and the upcoming missions 4, 5, 5P and 6) provide together a comprehensive picture of Earth’s health with unprecedented wealth of measurements — both in quality and quantity, opening the floor to more extensive research and paving the way to new fields of research. And all data is freely available and free of charge.

However challenges are also emerging

The ongoing and upcoming amount of data being produced will allow for things which would be impossible to be done in the past — but also poses new challenges. This ever increasing rate at which satellite data volume is growing, is in fact overwhelming. And much, so much more, is yet to come. By the end of 2017, the operational Sentinel-1, -2 and -3 satellites alone will continuously collect a volume of 20 Terabytes per day.

Yep. 20 Terabytes. That’s ‘just’ 20,000 GB every single day. The challenges come with storage and processing capacity needs to handling Earth observation data — not to mention time-consumption in running tasks. Want another example? Wagner (2015) gives a nice one: it could take around 2.5 years to download 1 Petabyte of Sentinel-1 data and a staggering 63 years to pre-process it on your own computer. Ouch.

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