Greenland, Iceland and Norwegian Seas Regional Climatology Version 3

What is the GINS Regional Climatology?

The GINS RC v3 is a set of seven decadal mean fields for temperature and salinity within the 50°N to 85°N and 45°W to 15°E domain comprised of the Greenland, Iceland, and Norwegian Seas and adjacent areas of the northern North Atlantic and Arctic Oceans. 

The seven decadal temperature and salinity climatologies use all available data in WOD23 from 1955 to 2022. 

There are six 10-year (1955–1964, 1965–1974, 1975–1984, 1985–1994, 1995–2004, 2005–2014) climatologies and one eight-year (2015–2022) climatology that were calculated for annual, seasonal, and monthly time periods. Seasons are as follows: Winter (January–March), Spring (April–June), Summer (July–September), and Fall (October–December).

An all-data climatology was computed by averaging all seven decadal climatologies and represents the long-term mean state of the ocean in the GINS region over the 1955–2022 time frame.

Decadal climatologies included in the GINS RC v3 are comprised of objectively analyzed temperature and salinity fields, and additional parameters including: 

• Statistical means
• Number of observations
• Standard deviations
• Standard errors of the mean
• Statistical mean minus analyzed
• Seasonal minus annual climatology
• Grid points

This is the first quality-controlled regional climatology of the GINS region with up to 1/10°x1/10° spatial resolution and seasonal/monthly temporal resolution for both temperature and salinity for seven consecutive decades.

How were the fields in this product analyzed?

Seasonal and annual fields are based on complete monthly analyses of all three horizontal grids (1°x1°, 1/4°x1/4°, and 1/10°x1/10°), which are computed by averaging seven decadal monthly analyses from 1955 to 2022. Seasonal fields at all depths above 1500 meters are computed from the average of the three months comprising each season (e.g., January, February and March for winter), while annual mean fields are computed by averaging the four seasonal fields at all depths. 

The annual analysis of measurements below 1500 meters is the mean of the four seasonal analyses, and only shows annual and seasonal fields (the monthly fields are not shown below 1500m depth). Annual, seasonal, and monthly fields for the seven individual decades are presented on 1°x1° and 1/4°x1/4° and  1/10°x1/10° grids. For the aggregated ocean climate state between 1955 and 2022 (i.e., the 'all averaged decades'), annual, seasonal and monthly fields are also shown for all three resolutions.

What are high resolution fields, and how do I use them?

Higher spatial resolution grids provide major advantages over coarser grids  (Seidov et al., 2016). They reveal more outliers and, more importantly, enable more well sustained gridded field structures because of the significantly shorter radius of influence in the objective analysis procedure, especially in regions with sharp gradients of the essential oceanographic parameter (e.g. temperature, salinity, etc.).

In the GINS subpolar latitudes, mesoscale elements of hydrographic fields are easier to recognize on maps with 1/10°x1/10° resolution. They are better preserved in the generated climatological fields, which makes high-resolution climatologies more valuable for ocean modeling and for ocean climate change analysis (Seidov et al., 2017, Mishonov et al., 2024b).

It is important to note that the high-resolution monthly temperature and salinity data coverage on the 1/10°x1/10° grid has more gaps than seasonal and annual timespans. In general, all high-resolution analyzed fields should be reviewed carefully before use in mission-critical   applications.

You should always review the data distribution and statistical mean arrays before using high-resolution analyzed temperature and salinity fields or their climatological means. Moreover, the monthly maps of objectively analyzed data on 1/10°x1/10° may show irregularities which are too strong in some regions with fewer profiles (more data gaps) and are, in our view, artefacts caused by interpolation and plotting. These cases are uncommon, but it's important to carefully review fields with these kinds of irregularities.

Area 

From 45°W to 15°E longitudes and from 50°N to 84.5°N latitudes

Temporal Resolution

All data from the WOD23 for the GINS domain were used to calculate seven decadal climatologies within the following time periods: 1955–1964; 1965–1974; 1975–1984; 1985–1994; 1995–2004; 2005–2014; and 2015–2022. The all-data climatology was calculated by averaging the seven individual decades listed above (see World Ocean Database 2023 Introduction).

Each decadal climatology consists of:

• Annual Fields: Computed as 4-seasons averages
• Seasonal Fields: Winter (Jan.-Mar.), Spring (Apr.-Jun.), Summer (Jul.-Sep.), Fall (Oct.-Dec.) computed as 3-month averages
• Monthly Fields

Spatial Resolution

The annual, seasonal, and monthly fields are all available on 1°x1°, 1/4°x1/4°, 1/10°x1/10° grids.

Vertical (Ocean Depth) Resolution

• Annual and Seasonal Fields: Calculated from 0 to 4000 m depth on 87 standard levels (from the sea surface to the maximum depth in the GINS domain)
• Monthly Fields: Calculated from 0 to 1500 m depth on 57 standard levels

Standard depth levels in the GINS regional climatology are the same as in the WOA23 (see Table 3 in the WOA23 documentation, doi: 10.25923/a78k-gq49 ).

Additional Fields

• Statistical means
• Number of observations
• Standard deviations
• Standard errors of the mean
• Statistical mean minus analyzed
• Seasonal minus annual climatology
• Grid points

Units

• Temperature Units: °C
• Salinity: Unitless on the Practical Salinity Scale-1978 [PSS].

Bathymetry 

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

Calculation Methods

The calculation methods used to create mean climatological fields are described in detail in the following publications: 

• Temperature: Locarnini et al., 2024
• Salinity: Reagan et al., 2024. 

Additional details regarding high-resolution climatological calculations can be found in Boyer et al., 2005. Radii of influence for the objective analysis procedure, including the 1/10° grid resolution.

GINS Regional Climatology Publications

• 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. International Journal of Climatology, 25(7), 931-945.
• Levitus, S., (1982): Climatological Atlas of the World Ocean. NOAA Professional Paper 13, 173 pp., U.S. Gov. Printing Office, Rockville, MD. ftp://ftp.library.noaa.gov/noaa_documents.lib/NOAA_professional_paper/NOAA_paper_13.pdf
• Locarnini, R.A., A.V. Mishonov, O.K. Baranova, J.R. Reagan, T.P. Boyer, D. Seidov, Z. Wang, H.E. Garcia, C. Bouchard, S.L. Cross, C.R. Paver, and D. Dukhovskoy (2024). World Ocean Atlas 2023, Volume 1: Temperature. A. Mishonov Technical Ed. NOAA Atlas NESDIS 89, doi: 10.25923/54bh-1613
• Mishonov A.V., T. P. Boyer, O. K. Baranova, C. N. Bouchard, S. Cross, H. E. Garcia, R.  A. Locarnini, C. R. Paver, J. R. Reagan, Z. Wang, D. Seidov, A. I. Grodsky, J. G. Beauchamp, (2024a): World Ocean Database 2023. C. Bouchard, Technical Ed., NOAA Atlas NESDIS 97, 206 pp., doi: 10.25923/z885-h264
• Reagan, J.R., D. Seidov, Z. Wang, D. Dukhovskoy, T.P. Boyer, R.A. Locarnini, O.K. Baranova, A.V. Mishonov, H.E. Garcia, C. Bouchard, S.L. Cross, and C.R. Paver (2024) World Ocean Atlas 2023, Volume 2: Salinity. A. Mishonov, Technical Editor, NOAA Atlas NESDIS 90, doi: 10.25923/70qt-9574
• Seidov, D., O.K. Baranova, T. Boyer, S.L. Cross, A.V. Mishonov, A.R. Parsons (2016). Northwest Atlantic Regional Ocean Climatology. NOAA Atlas NESDIS 80, Tech. Ed.: A.V. Mishonov. Silver Spring, MD, 56 pp. doi:10.7289/V5/ATLAS-NESDIS-80.
• Seidov, D., A. Mishonov, J. Reagan, and R. Parsons, 2017: Multidecadal variability and climate shift in the North Atlantic Ocean, Geophys. Res. Let., 44(10), 4985-4993, doi:10.1002/2017GL073644.
• Mishonov, A. V., Seidov, D., Baranova, O. K., Bouchard, C., Boyer, T. P., Cross, S. L., Larsen, K., Nyadjro, E. S., Parsons, A. R., Weathers, K. (2024b). High-Resolution Regional Ocean Climatologies with the Northwest Atlantic as an Example: A Review. Journal of Marine Science Research and Oceanography, 7(1), pp 01-32. https://dx.doi.org/10.33140/JMSRO.07.01.01