Environmental Thematic Maps and Graphics:
Summer sea surface salinity departures from climate normal reference period at a quarter degree grid

The title of this map is “Summer sea surface salinity departures (2005 to 2017) from climate normal reference period at a quarter degree grid.” This map provides a detailed visual representation of the average summer 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 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 summer sea surface salinity decreased the most in the Strait of Georgia. Salinity decreased in the Southern Shelf, southern Offshore Pacific, southern Gulf of St. Lawrence and the deepest areas of the Scotian and Newfoundland shelves, and increased in eastern Hudson Bay. The Arctic marine ecoregions had mixed areas of salinity increase and decrease.

Notes: The climate normal is the three-decade average of climatological variables from 1981 to 2010. Summer data are from July to September. 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.

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).