CLASSnmat version 2: monthly, global, gridded night marine air temperature data

Climate Linked Atlantic Sector Science (CLASS)nmat is a global dataset of monthly mean night marine air temperature (NMAT) that is produced on a 5° latitude by 5° longitude regular grid and covers the period since 1880.

The temperature values are taken from version 3.0.0 of the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) for the period 1880-2014 and from version 3.0.2 of ICOADS thereafter. The in situ air temperature readings recorded between one hour after sunset and one hour after sunrise have been extracted from ICOADS and the ship data have been adjusted to reduce the effects of varying thermometer heights. The data have been adjusted from their respective recording heights to each of three reference heights: 2m, 10m and 20m. The air temperature readings have been subjected to a quality-control procedure and then the values have been aggregated to form gridded averages, with corresponding uncertainty estimates.

This dataset has been developed under the following NERC-funded projects: GloSAT (NE/S015647/2), CLASS (NE/R015953/1) and AtlantiS (NE/Y005589/1).