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Northern North Pacific (NNP) Regional Climatology
Please note that this version of the regional climatology will be updated to include new data and improve the information section.

Overview: A set of analyzed temperature and salinity fields was computed for the NNP domain to assess long-term climatological tendencies in this important region of the North Pacific Ocean. The set is comprised of the objectively analyzed temperature and salinity fields as well as some additional parameters that may be useful for applied climate studies. These additional parameters include simple statistical means, data distributions, standard deviations, standard errors of the mean, observed minus analyzed, and seasonal minus annual distributions for both temperature and salinity. These parameters were computed using all data available in the World Ocean Database released in 2013 (WOD13). The maps and data are available for viewing and downloading. Since publication of the Climatological Atlas of the World Ocean (Levitus, 1982), objectively analyzed fields of essential oceanographic parameters, such as temperature, salinity, oxygen, etc., are traditionally referred to as "ocean climatology".

Area: The NNP domain is encompassed between 120.0°W and 155.0°E longitudes and between 50.0°N and 69°N latitudes.

Temporal resolution:

  1. All data from the WOD13 for the NNP domain were used to calculate six decadal climatologies within the following time periods: 1955-1964; 1965-1974; 1975-1984; 1985-1994; 1995-20014; 2005-2012. The all averaged decades climatology was calculated by averaging six individual decades listed above (see World Ocean Database 2013 Introduction).
  2. Each decadal climatology consists of
    1. Annual (computed as 12 months averages);
    2. Seasonal: Winter (Jan.-Mar.), Spring (Apr.-Jun.), Summer (Jul.-Sep.), Fall (Oct.-Dec.) computed as 3-months averages;
    3. Monthly fields.

Spatial resolution:

  1. Annual and seasonal fields are available on 1°x1°, 1/4°x1/4°, and 1/10°x1/10° latitude/longitude grids.
  2. Monthly fields are available on a 1°x1° and a 1/4°x1/4° grids only.

Vertical resolution:

  1. All annual and seasonal fields were calculated from 0 to 5500 m depth on 102 standard levels;
  2. All monthly fields were calculated from 0 to 1500 m on 57 standard levels.
Standard depth levels in the NWA regional climatology are the same as in the WOA13 (see Table 3 in the WOA13 documentation).

Objectives: Higher spatial resolutions – here the 1/10°x1/10° grid – provide major advantages in the areas where such resolutions are feasible and supported by data availability. The quality control on a higher-resolution grid reveals more outliers than an analysis on coarser grids. More importantly, with the significantly shorter radius of influence in the objective analysis procedure, the structure of the gridded fields is far better sustained, especially in regions with sharp gradients of the essential oceanographic parameter (temperature and salinity).

Units: Temperature units are °C. Salinity is unitless on the Practical Salinity Scale-1978.

Data: All data from WOD13 were used to generate the NWA mean and decadal climatologies. The description of employed datasets can be found in World Ocean Database 2013 Introduction.

Bathymetry: For all three grid resolutions, mean depth values at the center of a grid square with the respective resolution were extracted from the ETOPO2 World Ocean bathymetry.

Methods: The methods followed for calculating mean climatological fields are described in details in the following publications: Temperature: Locarnini et al., 2013, Salinity: Zweng et al., 2013.

Additional details on high-resolution climatological calculations are found in Boyer et al., 2005.

The updated table from (Boyer et al., 2005) provides radii of influence for the analysis procedure as follows:

Pass1° radius of influence1/4° radius of influence1/10° radius of influence
1892 km321 km253 km
2669 km267 km198 km
3446 km214 km154 km

Data formats:
Data are distributed in several formats:

  1. Comma Separated Values (CSV) format which gives latitudes and longitudes of the center of a grid box and the value at each depth in that grid box;
  2. ArcGIS shape-file format;
  3. netCDF format.

All procedures used for generating the NNP, al., 2012), Greenland-Iceland-Norwegian Seas (Seidov et al., 2013), and Northwest Atlantic (Seidov et al., 2016) regional climatologies are similar. A pilot study using the Arctic Regional Climatology has been recently published in a special issue of the Progress in Oceanography (Seidov et al., 2015).


Boyer, T., S. Levitus, H. Garcia, R. A. Locarnini, C. Stephens, J. Antonov, 2005: Objective analyses of annual, seasonal, and monthly temperature and salinity for the world ocean on a 0.25 degree grid. Int. J. Clim., 25, 931-945.

Boyer, T. P., J. I. Antonov, O. K. Baranova, C. Coleman, H. E. Garcia, A. Grodsky, D. R. Johnson, R. A. Locarnini, A. V. Mishonov,T. D. O'Brien, C. R. Paver, J. R. Reagan, D. Seidov, I. V. Smolyar, M. M. Zweng, 2013: World Ocean Database 2013. Sydney Levitus, Ed.; Alexey Mishonov, Technical Ed.; NOAA Atlas NESDIS 72, 209 pp.

Boyer, T.P., O.K. Baranova, M. Biddle, D.R. Johnson, A.V. Mishonov, C. Paver, D. Seidov and M. Zweng, 2012: Arctic Regional Climatology, Regional Climatology Team, NOAA/NCEI (

Levitus, S., 1982: Climatological Atlas of the World Ocean, NOAA Professional Paper 13, U.S. Gov. Printing Office, Rockville, M.D., 190 pp.

Locarnini, R. A., A. V. Mishonov, J. I. Antonov, T. P. Boyer, H. E. Garcia, O. K. Baranova, M. M. Zweng, C. R. Paver, J. R. Reagan, D. R. Johnson, M. Hamilton, and D. Seidov, 2013: World Ocean Atlas 2013, Volume 1: Temperature. S. Levitus, Ed., A. Mishonov Technical Ed.; NOAA Atlas NESDIS 73, 40 pp.

Seidov, D., O.K. Baranova, M. Biddle, T.P. Boyer, D.R. Johnson, A.V. Mishonov, C. Paver and M. Zweng, 2013: Greenland-Iceland-Norwegian Seas Regional Climatology, Regional Climatology Team, NOAA/NCEI (

Seidov, D., J. I. Antonov, K. M. Arzayus, O. K. Baranova, M. Biddle, T. P. Boyer, D. R. Johnson, A. V. Mishonov, C. Paver and M. M. Zweng, 2015: Oceanography North of 60°N from World Ocean Database, Progress in Oceanography, v 132, p. 153-173; doi:10.1016/j.pocean.2014.02.

Seidov, D., O.K. Baranova, D.R. Johnson, T.P. Boyer, A.V. Mishonov and A.R. Parsons (2016), Northwest Atlantic Regional Climatology, Regional Climatology Team, NOAA/NCEI (, dataset doi:10.7289/V5RF5S2Q.

Zweng, M. M, J. R. Reagan, J. I. Antonov, R. A. Locarnini, A. V. Mishonov, T. P. Boyer, H. E. Garcia, O. K. Baranova, D. R. Johnson, D. Seidov and M. M. Biddle, 2013: World Ocean Atlas 2013, Volume 2: Salinity. S. Levitus, Ed., A. Mishonov Technical Ed.; NOAA Atlas NESDIS 74, 39 pp.