Average seawater temperature at 500m depth
in °C for the 1991 - 2020 climate normal period.

Climate normals, defined as 30-year averages of data by the World
Meteorological Organization (WMO), provide long-term means for
initializing models, environmental studies, checking in situ
observations, etc.

Comparing new observations to the most recent climate normal allows
one to assess whether or not current observations are within the
statistical norm in the context of the most recent 30-year
climatological background. Additional applications, such as
initializing boundary conditions for climate models or assessing
remotely sensed observations, also require a more recent
climatology.

=== Original Data Source ===
World Ocean Atlas 2023, Volume 1: Temperature.

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.

Citation:
Locarnini, R. A., O. K. Baranova, A. V. Mishonov,
T. P. Boyer, J. R. Reagan, D. Dukhovskoy, D. Seidov,
H. E. Garcia, C. Bouchard, S. Cross, C. R. Paver, and Z. Wang,
2023. World Ocean Atlas 2023, Volume 1: Temperature. A. Mishonov
Technical Ed. NOAA Atlas NESDIS (in preparation).

Citation URL:
https://www.ncei.noaa.gov/products/world-ocean-atlas