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JMA's global ocean heat content data

Updated on 20 Feb. 2023
Japan Meteorological Agency

Data on annual mean anomalies of global ocean heat content (OHC) are available for download.

Data description

Global OHC anomalies are calculated from monthly temperature analysis and monthly climatological salinity data.
Temperatures are analyzed objectively on monthly 1° grids for 26 levels at depths of 0 – 2000 m.
The analysis is based on in situ observations only.
The gridded OHC values are computed by vertically integrating the heat content for each level (0 – 2000 m). For more details, see the reference (Ishii et al., 2017).


Data are in ASCII format.
All values are stored as annual mean OHC anomalies from the 1991 – 2020 average in 1019 J.
Errors indicate one standard deviation.
Missing data are set to the value given in the header (-9.9999). The grids represent areas of 1°×1°.
The data array consists of 180 rows and 360 columns.
The cell in the first column of the first row shows the value for the grid box at (0.5°E, 89.5°N).
The cell in the second column of the first row shows the value for the grid box at (1.5°E, 89.5°N).
The cell in the 360th column of the 180th row shows the value for the grid box at (0.5°W, 89.5°S).


The first line of each record is a header indicating the relevant attribute. The header format is as follows:

# Year Month Day Row Column Missing Lon-Lat at (1,1) and Lon-Lat at (360,180) Unit
# 1980 null null 180 360 Missing = -9.9999 (1, 1) = (0.5E, 89.5N) and (360,180) = (0.5W, 89.5S) Unit: 10**19J

The second and third columns (i.e., the month and day) in the header are "null."

Sample program

ohcsample.ZIP - a sample Fortran90 program source file for reading data (179.5°E, 0.5°N) from specific years compressed in ZIP format.

Data file download

Each decade is archived in one file.
All files are compressed in ZIP format, and all file sizes are less than around 1 MB.

OHC1 standard deviation error
1955 – 1959 ohc_1955_1959.ZIP ohc_err_1955_1959.ZIP
1960 – 1969 ohc_1960_1969.ZIP ohc_err_1960_1969.ZIP
1970 – 1979 ohc_1970_1979.ZIP ohc_err_1970_1979.ZIP
1980 – 1989 ohc_1980_1989.ZIP ohc_err_1980_1989.ZIP
1990 – 1999 ohc_1990_1999.ZIP ohc_err_1990_1999.ZIP
2000 – 2009 ohc_2000_2009.ZIP ohc_err_2000_2009.ZIP
2010 – 2019 ohc_2010_2019.ZIP ohc_err_2010_2019.ZIP
2020 – last ohc_2020_last.ZIP ohc_err_2020_last.ZIP


The following citation should be included when these data are used:
Ishii, M., Y. Fukuda, H. Hirahara, S. Yasui, T. Suzuki, and K. Sato, 2017: Accuracy of Global Upper Ocean Heat Content Estimation Expected from Present Observational Data Sets. SOLA, Vol. 13, 163 – 167, doi:10.2151/sola.2017-030.