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

Estimate of the influence of river flow on the variability of salinity, based on a simple box model that only uses USGS river flow for input (top panel). We compare this to daily-measured (or better) depth-averaged salinity as measured by the ORCA moorings. Near-surface values are excluded to reduce transient, short-timescale variability in the observations. Comparison to adjusted river flow anomalies for a particular basin (lower panel) shows the influence of flow anomalies on salinity.

The estimates of salinity variance due to river freshwater input are considered "low-end" or minimum estimates because of the simplicity of the model and associated errors. A more advanced model, for example, might better approximate the lag between river flow changes, mixing intensity, and upper water column response.

Station Data

Climatology and anomaly values are calculated for various stations in Puget Sound. To view this information, you can select from the station(s) below.