Globally-gridded night-time marine air temperatures

Near surface air temperature over the oceans is a relatively unused parameter in understanding the current state of climate, but is useful as an independent temperature metric over the oceans and serves as a geographical and physical complement to near-surface air temperature over land. Though one other version of this dataset exists (HadMAT), it has been strongly recommended that various groups generate climate records independently, which is one goal here. This University of Alabama in Huntsville (UAH) study began with the construction of monthly night-time marine air temperature (UAH-NMAT) values from the mid-nineteenth century through to the present era. Data from the International Comprehensive Ocean and Atmosphere Data Set (ICOADS) were used to compile a complete time series of gridded UAH-NMAT. This time series went through significant quality control since there are many biases such as increasing ship height, solar deck heating, changing observing practices, etc. The time series of UAH-NMAT, once adjusted to a standard reference height, will be gridded to 0.5°, 1°, 2.5°, and 5.0° grid boxes and interpolated using the kriging interpolation technique. This study will present results which quantify the variability and trends and compare to current trends of other related datasets that include HadMAT, sea-surface temperatures (SST) and blended products (land surface air temperature and SST).