This dataset contains climatological monthly mean files of air-sea fluxes on a global grid in netCDF format produced at the National Oceanography Centre (NOC). It includes freshwater flux, heat flux and windstress and selected meteorological variables.

Each data file contains 12 climatological monthly means on a global 1 x 1 grid for a particular flux field:

Heat flux and windstress:

latent heat flux (hfls), net heat flux (hfns), sensible heat flux (hfss), precipitation (pr), net longwave flux (rls), net shortwave flux (rss), wind stress (eastward) (tauu), wind stress (northward) (tauv).

Units are W/m2 for the heat flux and N/m2 for the stress.

Also available are freshwater fields:

evaporation (emy), precipitation (pmy), net evaporation (epmy)

Units are m/yr in each case (divide by 12 to get m/month).

Meteorology fields are:

u10 - 10m wind speed, units m/s

t10 - 10m air temperature, units deg C

q10 - 10m specific humidity, units g/kg

sst - sea surface temperature, units deg C

ana - total cloud amount, units octas

slp - sea level pressure, units mb

The flux fields have been derived from the COADS1a (1980-93) dataset enhanced with additional metadata from the WMO47 list of ships. A full description of the fields is given in The Southampton Oceanography Centre (SOC) Ocean - Atmosphere, Heat, Momentum and Freshwater Flux Atlas (see link under Docs) and a parallel journal paper (Josey et al, 1999) describes the results of various evaluation studies (see links under Docs).

It is important to note that the quality of the fields has a strong spatial dependence which reflects the global distribution of ship observations. Quality is likely to be high in the well sampled North Atlantic & North Pacific but to decrease in the Southern Hemisphere. In particular, south of 40 S the errors in the fields are likely to be large and we recognise the existence of spurious features which have been generated during the objective analysis of the original raw fields. NOC stress that caution must be taken when interpreting the fields in this region.

In addition, note that the current version of the fields does not give closure of the global heat budget, the imbalance being a global mean net heat gain by the ocean of 29 W/m2. Work was carried out to identify regions in which NOC scientists believe the net heat gain has been overestimated.

Results from several regional comparisons against high quality meteorological buoy data indicate that in those regions for which comparisons have been possible the NOC net heat flux estimates agree well with independent buoy measurements. Hence, NOC have not applied global adjustments to the heat flux

components in order to balance the heat budget at this stage of their analysis. See NOC1.1a for adjusted heat fluxes.

Funding has been received from the Hadley Centre, UK Meteorological Office for the production and analysis of this dataset.

Please note that NOC1.1 - Previously the 'Original' SOC climatology (climatological and individual monthly fields)