Environmental Thematic Maps and Graphics:
Winter sea surface salinity departures (2005 to 2017) from the climate normal reference period at quarter degree grid

The title of this map is “Winter sea surface salinity departures (2005 to 2017) from the climate normal reference period at quarter degree grid.” This map provides a detailed visual representation of the average winter surface salinity change of Canada’s oceans.

On the page, there are three maps and two legends to the upper left and right. The first map (top) displays all of Canada, the second map (left) displays the West Coast, and the third map (right) displays the East Coast. On the maps there are small numbers corresponding to marine ecoregions.

The maps show the gridded change in salinity with shades of green, yellow, orange and red. The first legend (left) lists the map labels and corresponding marine ecoregions. On the second legend (right) salinity is measured using the Practical Salinity Scale (PSS). The legend contains eight categories: ≥1 (forest green), 0.5 to < 1 (deep green), 0.1 to < 0.5 (sage green), 0 to < 0.1 (light green), -0.1 to <0 (yellow), -0.5 to < -0.1 (pale orange), -1 to < -0.5 (orange), < -1 (red). The legend contains two boundary categories: fine dashed lines indicate provincial boundaries and fine black lines indicate marine ecoregion boundaries.

The maps show that compared to the 1981 to 2010 climate normal reference period, the 2005 to 2017 average winter sea surface salinity generally decreased in most of the Arctic, Pacific marine ecoregions, and Gulf of St. Lawrence and increased in the Strait of Georgia, coastal waters north of the Northwest territories, off the coast of Labrador, and southern Scotian Shelf.

Notes: The climate normal is the three-decade average of climatological variables from 1981 to 2010. Winter data are from January to March. Data are reported using the unitless Practical Salinity Scale (PSS), for more information please see http://salinometry.com/pss-78/ . Data for salinity in the Arctic Ocean are sparser than in other regions. In particular, winter salinity data are more scarce and the modelling methods used could result in artificially high salinities for this season in some regions of the Arctic Ocean.

Sources:
Zweng, M. M., et al., 2018. World Ocean Atlas 2018: Volume 2: Salinity. A. Mishonov Technical Ed., NOAA Atlas NESDIS 82, 50 pp., https://www.nodc.noaa.gov/OC5/SELECT/woaselect/woaselect.html (accessed May 31st 2020).