The main objectives of the GNSS (Global Navigation Satellite System) Receiver for Atmospheric Sounding (GRAS) are to provide stratospheric and tropospheric temperature and humidity profiles that can be assimilated into NWP models.
27 April 2021
27 May 2020
In addition, GRAS provides navigation solutions of the Metop satellite position along its orbit.
What is GRAS?
The GRAS instrument receives high quality radio signals from GPS navigation satellites, occulting the Earth atmospheric limb, through a tangential path through the Earth's atmosphere. As such, GRAS is not just an instrument, but requires a full system to provide products. GRAS provides a minimum of 500 atmospheric profiles per day by a process of GPS radio occultation.
Other EPS instruments
IASI is the main payload instrument for the purpose of supporting Numerical Weather Prediction.
GOME-2 is used to get a detailed picture of the total atmospheric content and vertical profile of ozone.
Microwave Humidity Sounder (MHS)
The MHS is designed to collect information on various aspects of the Earth's atmosphere and surface.
SARSAT instruments help search and rescue authorities save thousands of lives around the world.