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

Abstract

Abstract 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.