peetfran quarraliah pansofee
Helen Drewski
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The World Ocean Atlas 2023 Dissolved Oxygen, Apparent Oxygen Utilization, and Dissolved Oxygen Saturation version 1.0 (released Feb. 2024) has been updated to version 1.1 as of May 30, 2024. A small change to the profiling float O2 data adjustment was made to allow for internal consistency with other independent types of O2 observations.
The World Ocean Atlas (WOA) is a collection of objectively analyzed, quality controlled temperature, salinity, oxygen, phosphate, silicate, and nitrate means based on profile data from the World Ocean Database (WOD). It can be used to create boundary and/or initial conditions for a variety of ocean models, verify numerical simulations of the ocean, and corroborate satellite data.
A new version of the WOA is released in conjunction with each major update to the WOD, the largest collection of publically available, uniformly formatted, quality controlled subsurface ocean profile data in the world.
A "normal" is defined by the World Meteorological Organization (WMO) as the 30-year average of data for a particular variable, calculated for a uniform time period. Normals provide long-term means for initializing models, environmental studies, checking in situ observations, etc.
Normals establish a baseline that can help researchers determine whether or not current observations are within the statistical norm in the context of the most recent 30-year climatological background.
analysis.for
FORTRAN program to print out a 10x10 degree latitude-longitude area from a user requested file
analysis.c
C program to print out a 10x10 degree latitude-longitude area from a user requested file
analysis.exe
DOS executable version of the "analysis.for" program
analysis_64.exe
64 bit executable version of the "analysis.for" program
anlyxyz.for
FORTRAN program which writes the entire 360x180 degree latitude-longitude grid into a comma-separated-value output file
anlyxyz_64.exe
64 bit executable version of the "anlyxyz.for" program
WOA 2018WOA18 was released September 30, 2018. It includes approximately 3 million new oceanographic casts added to the WOD, as well as renewed and updated quality control. The WOA18 temperature and salinity fields were released preliminarily to crowd source quality assurance from the WOA user community, which has successfully identified suspect features in previous releases.
WOA 2013World Ocean Atlas 2013 version 2 (WOA13 V2) contains objectively analyzed 1 climatological fields of in situ temperature, salinity, dissolved oxygen, Apparent Oxygen Utilization (AOU), percent oxygen saturation, phosphate, silicate, and nitrate at standard depth levels for annual, seasonal, and monthly compositing periods for the World Ocean. It also includes associated statistical fields of observed oceanographic profile data interpolated to standard depth levels on 5, 1, and 0.25 grids.
WOA 2009World Ocean Atlas 2009 (WOA09) is a set of objectively analyzed (1 grid) climatological fields of in situ temperature, salinity, dissolved oxygen, Apparent Oxygen Utilization (AOU), percent oxygen saturation, phosphate, silicate, and nitrate at standard depth levels for annual, seasonal, and monthly compositing periods for the World Ocean. It also includes associated statistical fields of observed oceanographic profile data interpolated to standard depth levels on both 1 and 5 grids.
Cite as: Levitus, Sydney; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2013). NODC Standard Product: World Ocean Atlas 2009 (NCEI Accession 0094866). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. -page/bin/iso?id=gov.noaa.nodc:0094866. Accessed [date].
WOA 2005World Ocean Atlas 2005 (WOA05) is a set of objectively analyzed (1 grid) climatological fields of in situ temperature, salinity, dissolved oxygen, Apparent Oxygen Utilization (AOU), percent oxygen saturation, phosphate, silicate, and nitrate at standard depth levels for annual, seasonal, and monthly compositing periods for the World Ocean. It also includes associated statistical fields of observed oceanographic profile data interpolated to standard depth levels on both 1 and 5 grids.
Levitus, Sydney; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2013). NODC Standard Product: World ocean atlas 2005 (4 disc set) (NCEI Accession 0097967). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. -page/bin/iso?id=gov.noaa.nodc:0097967. Accessed [date].
WOA 2001The World Ocean Atlas 2001 (WOA01) contains ASCII data of statistics and objectively analyzed fields for one-degree and five-degree squares generated from World Ocean Database 2001 observed and standard level flagged data.
The ocean variables included in the atlas are: in-situ temperature, salinity, dissolved oxygen, apparent oxygen utilization, percent oxygen saturation, dissolved inorganic nutrients (phosphate, nitrate, and silicate), chlorophyll at standard depth levels, and plankton biomass sampled from 0 - 200 meters.
Levitus, Sydney; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2013). NODC Standard Product: World Ocean Atlas 2001 (6 disc set) (NCEI Accession 0095600). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. -page/bin/iso?id=gov.noaa.nodc:0095600. Accessed [date].
The temperature anomaly fields calculated in conjunction with "Warming of the World Oceans" (Science, 2000) have a systematic error for years 1997 and 1998. Sippican started distributing XBT recording software with the Hanawa et al. (1995) depth equation as default in August, 1996. We were unaware of this and continued to apply a depth correction to XBT profiles from all T4, T6, and T7 XBT probes, which was necessary due to errors in the original default depth equation used on Sippican XBT software. The result of applying the depth correction to profiles which used the Hanawa depth equation was calculated depths deeper than the actual depths. In regions where temperature decreases with increasing depth, this resulted in the appearance of "warmer" water at these depths. Although the new Sippican software was not (and is still not) universally distributed, sufficient numbers of XBTs in 1997 and 1998 were recorded with this software to artificially inflate the positive temperature anomalies for these years.
This error does not affect the conclusions of the Science paper, since years 1997 and 1998 were not used to calculate the rate of change of ocean heat content. However, the 1997 and 1998 yearly temperature anomaly fields were made available online. Thus we recommend that people who downloaded these data and used them in their studies should revise their results using the updated temperature anomaly fields.
The differences between each scale are small (on the order of 0.01C) and should not have dramatic effect on the climatological means, except possibly at very deep depths. Salinity values are on the Practical salinity scale (PSS-78). Pre-1978 salinity values converted from conductivity may have used a different salinity scale. Pre-conductivity salinities use the Knudsen method.
Temperature and salinity are based on a mean climatological field from 1955-2017 (the average of six decadal climatological means). Oxygen, phosphate, silicate, and nitrate climatological means pull from every year in the database (1900s to present).
Climatologies are long-term means calculated from large, varied datasets that include measurements taken with different instruments and capture methods. These varying calibration standards, along with factors like data sparsity and time bias (some areas have more measurements in specific subset of the overall time span) make it difficult to provide a simple accuracy assessment.
We ensure accuracy in other ways, like storing the most accurate temperature readings possible (3 digits past the decimal point). We also provide standard deviation and standard error of the mean fields to contextualize the spread of values in any geographic area over the long term.
The Pacific, Indian, and Atlantic basin masks are available in the heat content netCDF files accessible from Global Ocean Heat and Salt Content. South encompasses all latitudes (box centers) -89.5 to -0.5. If netCDF is not convenient, we have a full basin mask (all depths) in a comma-separated file for the WOA which follows the same boundaries, but must be manipulated somewhat. Use just the surface level. The list of codes corresponding to the basins are found in appendix one (page 11) of the WOA Documentation.
Access vertical temperature and salinity profiles through WOAselect. The program will generate a data display graphic that includes links in the top left corner for comma delimited ASCII and ArcGIS shapefiles. These files contain standard depths for the chosen geographic area for the given variable and time period. Download temperature and salinity climatologies separately, and download each month separately. Alternatively, download a full set (monthly, seasonal, annual) of mean fields for each variable in WOA18 data and select the area from these gridded fields.
Standard deviation, standard error, and data distribution are calculated from all the data in the WOA, while the climatological mean (and the statistical mean) for January are average values for Jan. 1955-1964, Jan. 1964-75, ... Jan. 2015-18, the standard deviation values are the standard deviation of all Jan. data regardless of year.
The analysis procedure addresses this problem by using a fairly large radius of influence (880km for the first pass) and using seasonal values as the first guess for each month (annual values for each season), so the analyzed value and decadal means still reflect a six decadal balance in most cases. Note that standard deviation, standard error of the mean, and data distribution fields for the decadal averages are not averages of the six decadal fields. The standard deviation field associated with the decadal averaged objectively analyzed field is actually an all-data (all time period) field. There are standard deviation fields for each of the six decades that demonstrate the different standard deviations between each decade - but the standard deviation field provided with the decadal averaged field can be skewed in some areas, especially the southern Hemisphere, toward the Argo era.
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