Puget Sound Metrics
What causes salinity to change?
This metric shows how buoy salinity observations (orange line) vary compared to climatology (gray line) and a model that estimates the salinity changes only due to the influence of rivers and rain (blue lines). If the modeled changes in salinity parallel or track the salinity observations, this means that rivers and rain explain most of the variability in salinity. Offsets between model and observations are due to the accumulated influence of changes in the salinity of water entering Puget Sound and/or model errors and limitations. If the model line is below (or above) the observations, this suggests that the oceanic input waters were saltier (or fresher) than average over time. Click on different basins to see their information. Read More
Changes in Puget Sound salinity can have profound impacts on estuarine circulation as well as water column stratification, both of which can drive ecological processes. For instance, the strength of stratification can influence when or whether phytoplankton bloom. Since salinity in Puget Sound can change from differences in its oceanic source water or from freshwater input into Puget Sound such as from rivers, precipitation, and groundwater, there is often uncertainty about the causes of salinity change.
Here we created a simple salt conservation model that captures the salinity variability that is due to changes in rivers and rain. By comparing the model salinity to observed UW/NANOOS ORCA buoy salinity, we can gauge what is causing the salinity anomalies---that is, changes in freshwater input, changes in oceanic source water, or both.