ATLAS-8 describes the collection of data compiled from MOHSST6 and represents a major upgrade of ATLAS-7. Most files in ATLAS-8 contain data through December 1995, except where indicated.
The bucket corrections for the SST data are from Folland and Parker, 1995 (see Ref. 1). The SST climatology is based on work described by Parker, D.E., et al, 1995 (see Ref. 4).
The surface flux values are derived from work by Zhongxiang Wu using an updated version of the Comprehensive Ocean Atmosphere Data Set (COADS) and a modified set of bulk equations recently recommended by the oceanographic community (see Ref. 6 ).
The reference period for the climatologies and anomalies is 1961 to 1990, except for the heat flux data which are for 1949 to 1990.
The datasets used to compile ATLAS-8 are:
MOHSST6 (Met Office Historical Sea Surface Temperature) describes SST data compiled in January 1996. This dataset contains monthly values of SST anomaly from 1865 to 1995 on a 5° x 5° grid. These anomalies are with respect to 1961-1990 normals. More recent in-situ data have been added and the coverage and quality control procedures have also been improved: Parker, D.E., et al, 1995 (see Ref. 3). Normals and statistics (standard deviations, lag correlations etc.) have been recalculated using the same ATLAS-7 techniques and in most cases the same programs have been used.
MOMAT4N describes the Met Office Historical Night Marine Air Temperature data used to create ATLAS-8. This data set contains monthly values of NMAT anomaly from 1856 to 1995 on a 5° x 5° grid. These anomalies are with respect to 1961-1990 normals. The data have similar corrections to those in ATLAS-7, but night is defined as from sunset + 1 hour to sunrise + 1 hour to avoid residual solar heating of the ship's decks.
You may view an example of plot of Sea Surface Temperature and night marine air temperature anomalies (with respect to 1961-90) for the E. Tropical Pacific (from the Met Office).
MOHAST describes the Met Office Historical Air-Sea Temperature difference data. In ATLAS-8 the climatology for 1961 to 1990 has been calculated using individual nighttime observations of air-sea temperature difference, with the difference between the GISST2.0 SST climatology and the MOHMAT4N Night Marine Air Temperature (NMAT) climatology as background field.
Please refer to Atlas-8 Data set names and Content for details of the data files available on the CD-ROM (HDF version).