A spatiotemporal analysis of the relationship between near-surface air temperature and satellite land surface temperatures using 17 years of data from the ATSR series

The relationship between satellite land surface temperature (LST) and ground-based observations of 2 m air temperature (T 2m ) is characterized in space and time using > 17 years of data. The analysis uses a new monthly LST climate data record (CDR) based on the Along-Track Scanning Radiometer series, which has been produced within the European Space Agency GlobTemperature project (http://www.globtemperature.info/). Global LST-T 2m differences are analyzed with respect to location, land cover, vegetation fraction, and elevation, all of which are found to be important influencing factors. LST night (~10 P.M. local solar time, clear-sky only) is found to be closely coupled with minimum T 2m (T min , all-sky) and the two temperatures generally consistent to within ±5°C (global median LST night -T min = 1.8°C, interquartile range = 3.8°C). The LST day (~10 A.M. local solar time, clear-sky only)-maximum T 2m (T max , all-sky) variability is higher (global median LST day -T max = −0.1°C, interquartile range = 8.1°C) because LST is strongly influenced by insolation and surface regime. Correlations for both temperature pairs are typically > 0.9 outside of the tropics. The monthly global and regional anomaly time series of LST and T 2m —which are completely independent data sets—compare remarkably well. The correlation between the data sets is 0.9 for the globe with 90% of the CDR anomalies falling within the T 2m 95% confidence limits. The results presented in this study present a justification for increasing use of satellite LST data in climate and weather science, both as an independent variable, and to augment T 2m data acquired at meteorological stations