Regional Climatology: The Gulf of Mexico

Note: This is a preliminary version of the regional climatology which will be replaced. Many more data have been added to the World Ocean Database since work on the regional climatology commenced. The climatology will be recalculated using these new data.

Climatologies updated 10/05/2011. Previous climatologies contained incorrect depth values for temperature and salinity at one-degree and one quarter-degree grids. One tenth degree climatologies were also updated.

Area: The area encompassed is from 98.0 W^o to 75.0 W^o longitude and from 15.0 N^o to 35.0 N^o latitudes. This includes the entire Gulf of Mexico, the Northern Caribbean Sea, a small part of the western Atlantic along the US coast and a small part of the Pacific Ocean along the Mexican coast.

Horizontal resolution: All variables are available on a 1x1 latitude/longitude grid. Temperature and salinity are also available on a 1/4 degree grid, and for the 1/10th degree grid for some compositing periods.

Time resolution: All climatologies for all variables use all available data regardless of year of measurement. Climatologies were calculated for the annual (all-data), seasonal, and monthly time periods. Seasons are as follows: Winter (Jan.-Mar.), Spring (Apr.-Jun.), Summer (Jul.-Aug.), Fall (Sep.-Dec.). 1/4 degree and 1/10th degree climatologies are available for temperature and salinity only for the annual and seasonal compositing periods.

Vertical resolution: Oxygen, phosphate, nitrate, and silicate are available on 33 standard levels from the surface to 5500 m. depth (Table 1a) for the annual time period and to various depths for seasonal and monthly time periods as per Table 1a.

Table 1 a

Temperature and salinity are available on 102 standard levels with higher vertical resolution, also from the surface to 5500 m. (Table 1b) depth for annual and seasonal time periods, and from the surface to 1500 m. (57 standard levels) for the monthly time period.

Table 1 b

Additional fields: In addition to climatological mean fields, fields of statistical means (before objective analysis), standard deviation, standard error, data distribution, observed minus analyzed, and difference of time period from annual climatological mean, are also available.

Units: Temperature units are ^oC. Salinity is unitless on the Practical Salinity Scale-1978 [PSS], oxygen units are ml/l, phosphate, nitrate, and silicate units are micromoles/liter.

Data used: All data from the area found in the World Ocean Database (WOD) as of the end of 2010. For a description of this dataset, please see World Ocean Database 2009 Introduction (pdf, 3.40 MB).

Bathymetry used: For the one-degree and 1/4-degree climatologies, the mean value within a grid square from the ETOPO2 was used. For the 1/10th-degree climatologies, the mean value within a grid square from the ETOPO1 was used.

Method: The method followed for calculation of the mean climatological fields is as detailed in the following publications: Temperature: Locarnini et al., 2010, Salinity: Antonov et al., 2010, Oxygen: Garcia, et al., 2010a, Phosphate, Silicate, Nitrate: Garcia et al.., 2010b.

Additional details on the 1/4 degree climatological calculation are found in Boyer et al., 2005.

The table from this publication giving radius of influence for the analysis procedure can be filled out with values for the 1/10th degree procedure as follows:

Data formats: data are presented in a comma separated value (csv) format which gives lat/lon of the center of a grid box and the value at each depth in that grid box. Data are also presented in an ArcGIS compatible format and in netCDF.