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World Ocean Atlas 2001 (five-degree objectively analyzed fields and statistics)

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Instructions for downloading and reading GZIP compressed data files. If you have problems downloading the data, you may try to ftp data using the following address:
This is a searchable WOA01 inventory table. Where: a = annual, s = seasonal, m = monthly.
To download the data click on button of your choice.
Number of
Unanalyzed mean Standard deviation Standard error ALL FIELDS
Time period Time period Time period Time period Time period Time period
Variables a s m a s m a s m a s m a s m
Dissolved oxygen
Apparent oxygen utilization
Percent oxygen saturation

Data are organized by variable. Within each variable directory, the data are stored by time period: annual, seasonal, and monthly. Each time period directory contains the following file types:

  • Analyzed mean fields (an) - one-degree all-data objectively analyzed mean. For temperature, salinity, and oxygen, an denotes an average of either the 12 monthly analyses (used to compute the annual analysis at and above 1500 meters), the 3 monthly analyses (used for the seasonal analyses), or the 4 seasonal analyses (used for the annual analysis below 1500 meters). For nutrients and chlorophyll data, an denotes the average of the 4 seasonal analyses. For annual at and above 1500 meters, this is the average of the 12 monthly analyses, for annual below 1500 meters, this is the average of the 4 seasonal analyses, for seasonal means this is the average of the appropriate 3 monthly analyses that comprise each season)
  • Seasonal or monthly fields minus annual fields (ma) - one-degree seasonal and monthly analyzed mean minus annual analyzed fields
  • Grid point fields (gp) - one-degree number of grid points which contain data within the radius of influence for each grid box
  • Data distribution field (dd) - one-degree and five-degree geographic distribution of data used in analysis
  • Standard deviation field (sd) - one-degree and five-degree standard deviation from the mean
  • Standard error of the mean (se) - one-degree and five-degree standard error of the mean
  • Means (mn) - one-degree and five-degree unanalyzed means for all data used in analysis
  • Unanalyzed minus analyzed (oa) - analyzed field subtracted from the one-degree unanalyzed (raw) means

Data files have the following naming conventions:


[v] = variable:
t = temperature
s = salinity
o = dissolved oxygen
x = percent oxygen saturation
a = apparent oxygen utilization
p = phosphate
n = nitrate
i = silicate
c = chlorophyll
z = zooplankton biomass

[tp] = time period:
00 = all data annual
13 - 16 = seasons (starting with 13 = Winter (Jan-Mar))
01 - 12 = months (starting with 01 = January)

[ft] = file type:
an = all-data analyzed mean
dd = number of observations
sd = standard deviation of data
se = standard error of the mean of data
mn = raw (unanalyzed) mean of data
oa = unanalyzed (raw) mean minus analyzed field
ma = seasonal or monthly fields minus annual fields
gp = number of grid points containing data within the radius of influence around present grid point

[g] = grid size:
1 = one-degree square file
5 = five-degree square file

  Last modified:    Thu, 23-Apr-2015 19:57 UTC
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