Environmental Thematic Maps and Graphics:
Sea surface salinity departures (2005 to 2017) from the climate normal reference period, by depth class, marine ecoregion and season

The title of this map is “Sea surface salinity departures (2005 to 2017) from the climate normal reference period, by depth class, marine ecoregion and season.” This map provides a visual representation of the average annual and seasonal surface salinity change of Canada’s oceans.

On the page, there are five maps and a legend to the upper left. The first map (top right) displays average annual surface salinity change, the second map (middle left) displays average spring surface salinity change, the third map (middle right) displays average summer surface salinity change, the fourth map (bottom left) displays average fall surface salinity change and the fifth map (bottom right) displays average winter surface salinity change.

The maps show the change in salinity with shades of green, yellow, orange and red 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 three boundary categories: fine dashed lines indicate provincial boundaries, fine black lines indicate marine ecoregion boundaries and fine grey lines indicate marine depth classes.

The maps show that, compared to the 1981 to 2010 climate normal reference period, the 2005-2017 average annual and seasonal sea salinity generally decreased in the Arctic, Gulf of St. Lawrence and on the West Coast, and increased in Hudson Bay, Western Arctic and East Coast.

Notes: The climate normal is the three-decade average of climatological variables from 1981 to 2010. Winter data are from January to March with other seasons following sequentially. 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.

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