Puget Sound Metrics
How does weather affect Puget Sound's temperature?
This metric shows when the atmosphere is warming or cooling Puget Sound. By comparing observations to the average, we can see excursions in either case. Above average warming (orange area) indicates when Puget Sound is receiving more than normal heat, and the converse indicated by blue area. A second plot shows how the accumulation of this warming or cooling would change the water temperature in the absence of other influences. Because of the dominant influence of solar radiation, i.e. sunshine, on heating, water stratification, and phytoplankton bloom formation, we include two plots for just this quantity as well. We look at two different general regions in Puget Sound (north and central) because of consistent differences we've seen between the two locations.
With this metric, we can evaluate the cause of temperature changes: A strong correlation of observed seawater temperature anomalies with those in surface heating indicate that temperature anomalies are mostly being driven locally, and not due to source water changes; a weak correlation would suggest source water changes are driving the Puget Sound temperature anomalies. Read More
Water temperature changes in Puget Sound can be driven by both source water changes and changes in the local rate of heating or cooling by the atmosphere, just as salinity is affected by source waters and local freshwater input. This metric tracks the anomalies in the heat that enters or leaves Puget Sound through the water's surface. This quantity is known as the total surface heat flux, which combines four different heat flux terms: 1) the shortwave (solar) and 2) longwave (infra-red) radiative heat fluxes and the 3) latent (from evaporation) and 4) sensible (from air-sea temperature differences) surface fluxes. Summing the anomalies in this heating rate over time gives an indication of the heat lost or gained through the surface, presented as a temperature anomaly (for a given water column thickness). Many PSEMP groups observe temperatures and calculate anomalies, but the cause of the changes has not been known.
Map showing data sources for heat flux calculations with cross-hatching indicating the two general regions for the flux estimates, i.e. North Puget Sound and Central Puget Sound.