Next Generation Climate Instrument Calibrated in the UK
23 Jun 2015



A next generation satellite basedsensor that is designed to advance our understanding of climate change has left the UK after a series of very challenging tests, and is en-route to the south of France for installation on the Sentinel 3 spacecraft.



A next generation satellite based sensor that is designed to advance our understanding of climate change has left the UK after a series of very challenging tests, and is en-route to the south of France for installation on the Sentinel 3 spacecraft.  

This major milestone in the life of The  Sea and Land Surface Temperature Radiometer (SLSTR) was reached as the sensor departed  the Science and Technology Facilities Council (STFC) RAL Space Centre for  Calibration, heading for integration with the Sentinel 3 satellite in Cannes,  having undergone a series of thermal vacuum and calibration tests. The  calibration is to assure the instrument’s highly accurate measurements of  global Earth surface temperatures for climate monitoring. 

The sensor, which National Centre for Earth Observation (NCEO) experts  will use for a range of climate research, is particularly designed to derive  Sea-Surface Temperatures (SSTs). To get  maximum understanding of climate, these new data will be carefully combined  with SST from previous satellite instruments to measure changes across decades.Data from SLSTR will  provide continuity of the climate quality sea surface temperature (SST) data collected by the Along Track Scanning Radiometer (ATSR), which over the last 20 years has much improved spatial and temporal coverage.Simulation of the interplay of ocean and atmosphere is crucial to being able to predict future tendencies of the weather and climate, and SST that will be used by climate modellers to test their models. 

Professor Chris Merchant of NCEO and University of  Reading said, "We are very much looking forward to obtaining data from the  first Sentinel 3 mission. Because of SLSTR's design and calibration, the sea surface  temperature measurements we will derive from its images should be very  trustworthy. This helps us track the behaviour of climate.”

SLSTR has been developed through a  collaboration between Selex ES (Florence), Jena Optronik, and STFC-RAL Space  for the ESA/EU Copernicus Sentinel 3 Satellite led by Thales Alenia Space in  Cannes. 

Dr Chris Mutlow, Director of RAL Space  said "SLSTR is a second generation SST sensor which will carry on the climate  observations started by the ATSR programme. The successful completion of the  SLSTR instrument calibration has required a great deal of hard work from our  team at RAL over the last few months, and represents a major milestone for  ESA/EU and all the contractors around Europe who have spent years building the  instrument. Like the rest of the science and operational communities we are now  keen to have SLSTR in space, operational and delivering high-quality SST data  to users”.

The calibration was performed in a purpose built rig designed to allow  the SLSTR instrument to view the different calibration sources under carefully  controlled conditions that replicates the in-flight environment. The measurements ensure that the calibration  of the data generated by SLSTR can be traced to reference standards as required  for accurate climate monitoring.

Figure 1 (below) shows Sea Surface Temperature changes based on data from the world leading UK Along Track Scanning Radiometers (ATSR). Dashed lines are estimates from in situ data sources.Solid lines are satellite data. The globes show during and after a big El Nino Southern Oscillation with red = warm; blue = cold. In an El Nino year (top), global temperatures are much higher on average than in a La Nina year (bottom) with temperature patterns which drive global weather. 


These activities require major computing power, and the UK has created a facility for collecting and processing large volumes of SLSTR and other data, at Harwell. 

Professor John Remedios, Director  of NCEO said "The Along Track Scanning Radiometers (ATSRs) and the new  Sea- and Land- Surface Temperature Radiometers (SLSTRs) show how the UK is  delivering significant evidence regarding the magnitude of change in ocean  temperatures. The high quality data from these instruments also serves many  operational applications which add value to this core mission which involves  many leading UK scientists.”

NCEO  experts will be using the SLSTR instrument to provide essential new information  on the land including fires and land surface temperature. It has two specifically designed  detector systems which are sensitive enough to detect fires burning across as  little as 100 m², which is only 1/10000th of the area covered by a single SLSTR  pixel. Professor Martin Wooster of NCEO  and King's College London hopes to use this important data to map the radiative  heat emitted by fires burning worldwide, and relate this to emissions of carbon  dioxide and other gases and aerosols. In an El Nino year, the impact of fires  on Earth's land and atmosphere can be especially severe, as was the case in  1997-1998. 

For more information please contact: RAL Space Enquiries