New, advanced instrument to boost quality of data
EUMETSAT Remote Sensing Scientist Anne O’Carroll talks about Sentinel-3’s contribution to measuring the temperature of the surface of the Earth’s oceans and seas and why this is important
Measurements of sea surface temperature (SST) are crucial for operational weather forecasting, operational ocean forecasting and for monitoring the Earth’s climate.
Satellites were first used to regularly measure SSTs in the 1980s, representing a major improvement in our ability to accurately determine the temperature of the surface of oceans and seas.
When Sentinel-3A is fully operational, another significant step forward will be achieved thanks to the Sea and Land Surface Temperature Radiometer (SLSTR) it will carry onboard, currently the most advanced instrument of its kind.
EUMETSAT Remote Sensing Scientist and SST expert Anne O’Carroll said the greater accuracy and higher quality of data expected from the SLSTR is due to its being designed to take two views of its path as it orbits the Earth, as well as having on-board two infra-red sources to be able to continually compare and calibrate the measurements.
"We expect the SLSTR to be a very high quality data source that can be used to correct other sea surface data sources"
“An important feature of SLSTR is the design of the dual-view sensor,” O’Carroll said. “Measuring through two atmospheric paths enables more accurate sea surface temperatures to be obtained.
“We expect the SLSTR to be a very high quality data source that can be used to correct other sea surface data sources.
“It has a very advanced atmospheric correction ability, which means it can better correct for uncertainties and biases introduced by water vapour and aerosols in the retrieval process.”
O’Carroll said there has been a gap in this area since the loss of the Envisat satellite in 2012 and she is looking forward to the challenges involved in understanding the new characteristics of the SLSTR.
“Because it’s a more advanced instrument, it makes it more exciting,” she said. “SLSTR is a new design of instrument with a much wider swath and more complex characteristics to the Advanced Along Track Scanning Radiometer (AATSR) that was flown on Envisat.”
The Sentinel-3 marine mission data will be disseminated by EUMETSAT via the organisation’s established channels.
EUMETSAT’s goal is to offer service providers and users a multi-mission, integrated data stream, combining the data from Sentinel-3’s instruments with those already being delivered by the organisation in support of operational oceanography from the joint European-US Jason-2 satellite, and soon from the recently launched Jason-3, as well as EUMETSAT’s existing Metop and Meteosat satellites and those of international partners in the US and China.
CMEMS will produce regional and further derived products including daily sea surface temperature products, O’Carroll said.
"We are working with the user communities to ensure that the processing and retrieval for sea surface temperature is the best that it can be"
National Meteorological Services will use these products for their operational analyses.
However, the data will be free and open to all.
“My involvement in the Sentinel-3 project has included a lot of preparation for the calibration and validation activities and that’s not just preparing our own tools and resources within EUMETSAT but also collaborating with the Ocean and Sea Ice Satellite Application Facility (OSI SAF), the European Space Agency, and the wider sea surface temperature community,” O’Carroll said.
“We are already collaborating with users and sea surface temperature experts to think about evolution and product improvements that we need. We are working with the user communities to ensure that the processing and retrieval for sea surface temperature is the best that it can be.”
In addition to her contribution to the Copernicus project and in collaboration with the EUMETSAT hyper-spectral team, O’Carroll works with the Infrared Atmospheric Sounding Interferometers (IASI) onboard the EUMETSAT Polar System satellites Metop-A and –B, which are credited with making essential improvements in global weather forecasting, as well as with the OSI SAF in relation to sea surface temperature.
For EUMETSAT missions, other than the Sentinel-3 marine mission, SST products are produced by the OSI SAF.
Satellite Application Facilities (SAFs) are dedicated centres of excellence for processing satellite data and are an integral part of the distributed EUMETSAT Application Ground Segment.
The OSI SAF is lead by Météo France and develops, processes and distributes products in Near Real Time.
OSI SAF products are used for operational weather forecasting, operational marine meteorology, operational oceanography, polar research, research in meteorology and oceanography and monitoring of the environment and climate.