Topic 1a - Why satellites?

Satellite Earth Observation is key to monitoring the health of our oceans. For more than 50 years, measurements from space have given scientists a worldwide prospective of the Earths climate and more recently, ocean topography.

The global oceans cover about 70% of the Earths surface, so the vast size and the often inhospitable nature means that we can not solely rely on in situ observations. The best way to efficiently and economically monitor this vast amount of water is to have satellites orbiting overhead watching the oceans constantly.

Now thanks to satellites we are developing operational oceanography, forecasting the ocean in 3D or 4D.

What can you retrieve from satellites?

Satellites provide long-term, continuous, and global data for key ocean parameters: sea level, ocean circulation, sea surface temperature (SST), ocean colour, sea ice, waves and winds.

Challenges and advances

The advent of ocean-observing satellites has launched a new era of marine discovery, but with this form of data monitoring also arise challenges, because satellites can only read the skin of the ocean.

Data modelling solutions can be used to simulate the evolution of ocean currents, temperature and other parameters consistent in space and time.

This allows you to infer information in the bed of the ocean from what you get from the sea surface.

Featured Educators:

  • Alain Ratier

  • Pierre Bahurel

View featured satellites on the satellite tracking app

Don’t forget you can download the video and transcript with the links on the right.


Animation: Sentinel-1 constellation

ESA video showing Sentinel-1’s orbit and swath coverage

To view the animation click the link below to go to the ESA website

Animation: Wave height

ESA video on how radar can detect wave height

To view the animation click the link below to go to the ESA website

Global Surface Reflectance and Sea Surface Temperature

MODIS provides frequent (every 1-2 days) global views of many of the Earth’s vital signs. This image shows a false-color land surface, derived using MODIS’ Surface Reflectance Product, and a false-color sea surface temperature map (red and yellow are warmer, blues are cooler).


How GNSS reflectometry works

Sea Surface Temperature and ice cover

Sea surface temperature and sea ice cover


Artist’s impression of Jason-2