The quality of HadCRU_MLE_v1.0_timeseries_monthly has been approved by Bruce T. T. Calvert on November 30, 2020. HadCRU_MLE_v1.0_timeseries_monthly is a further derived product (classifying as a level 4 data processing level) derived from various source datasets, including land surface air temperature anomalies of HadCRUT4, sea surface temperature anomalies of HadSST4, sea ice coverage of HadISST2, land mask data of OSTIA, the surface temperature climatology of Jones et al. (1999), the sea surface temperature climatology of HadSST3, surface elevation data of GMTED2010, and climate model output of CCSM4 for a pre-industrial control scenario. These source datasets either have had extensive quality control or are themselves further derived products based on source datasets that have had extensive quality control.