Salish Sea ORCA buoy observations over the last decade: warmer and saltier than normal anomalies and their persistence

• Main Authors: Newton, Jan, Carini, Roxanne
• Format: Text
• Language: English
• Published: Western CEDAR 2022
• Subjects: Admiralty Inlet; Carr; Ocean acidification; Orca
• Online Access: https://cedar.wwu.edu/ssec/2022ssec/allsessions/188; https://cedar.wwu.edu/context/ssec/article/3350/viewcontent/208_0b0d1500d5154fa19bbe7f452c0d3748.pdf

Profiling buoys take frequent (one to four times per day) measurements of water properties over the full water column. This allows characterization of short and long-term processes, including deep-water renewal events, surface influence of river runoff and heating, and tracking water mass properties. There are currently six ORCA (Oceanic Remote Chemical Analyzer) moorings in Puget Sound supported primarily by NANOOS and the Washington Ocean Acidification Center: South Hood Canal (Twanoh), central Hood Canal (Hoodsport), Dabob Bay, Admiralty Inlet (Hansville), Main Basin (Point Wells), and Southern Puget Sound (Carr Inlet). Profiling ORCA buoys have been operating in Puget Sound for over 10-15 years, depending on location. Anomalies of the real-time data (collected daily) compared to the long-term climatology illustrate times of higher than normal sea temperatures associated with marine heat waves, and times of higher than normal salinities associated with summer droughts. However, warm and salty anomalies have persisted in some years when those respective forcings (heat waves, summer droughts) were not occurring. We examine the record to elucidate annual differences and highlight basin differences in these signals. In the last six years, only 2020 and 2017 did not have predominantly warmer than average seawater temperatures. Higher than average salinities during summer have been noted for all years since 2014, except 2017. Temperature variations reflect the diverse oceanographic characteristics of Puget Sound’s sub-basins. Hood Canal, with strongly stratified waters, slow circulation, and deep water flushed by annual renewal, responds to atmospheric forcing differently than the Main Basin, which has stronger mixing that intensifies as this water feeds South Sound. Utilizing this longer view, we highlight emerging patterns and generalities in the anomalies, as well as sharp differences.