A new global land surface temperature dataset that – for the first time – combines both infrared and microwave satellite sensors.

Although satellite-derived temperature analysis is well established, the new dataset, which spans 25 years from 1995-2020 will be used to gain a more comprehensive understanding of environmental change.

Land surface temperature (LST) is one of 54 Essential Climate Variables (ECVs) defined by the Global Observing Climate System to monitor climate change.

“LST is integral to a radiative energy budget of the surface, and it provides the best approximation to the thermodynamic temperature that drives the surface energy,” says Dr Darren Ghent, who leads the research as part of ESA’s Climate Change Initiative.

ESA CCI Land Surface Temperature (1995-2020), version 2.0

“Our project provides an independent temperature data set for quantifying climate changes, complementing the near-surface air temperature ECV based on in situ measurements and reanalysis – it is being used to fill gaps in the analysis of near-surface air temperature, to correct for inhomogeneity or sparse in-station data, and to extract higher resolution information,” Ghent adds.

The combined use of both infrared and microwave sensors provides clear picture of LST at a global scale.

“This greatly increases scientists’ ability to monitor climate change as satellites observe the whole Earth every day, whereas the coverage of temperature records from ground-based meteorological stations is very patchy in comparison, particularly in polar regions where climate change is happening very quickly and in developing countries where the vulnerability of local populations can be relatively high.”

The data record show a stable increase in land surface temperature (LST) of 0.2C per decade, although there is a considerable regional variability within this.

The datasets are accompanied by an objective assessment of their accuracy and have been fully validated for consistency and stability to ensure they are suitable for climate trend analysis.

“The records can be applied to our understanding of urban heat islands and urban planning to map and henceforth mitigate heat stress,” says Ghent, “and we can distribute these findings to decision makers at the national and local level to address issues like vulnerability, urbanisation, and green space designation.”

Other applications for the LST data include agricultural and water management, tracking geothermal anomalies, and monitoring changes in the cryosphere.

The dataset is freely available from the CCI Open Data Portal.