Arctic | Climate and Oceanography MASTER’S POSTER PRESENTATION Volume transport of the Alaskan Coastal Current in late summer Presenter: Yasamin Bayley , ysb5@cornell.edu Phyllis Stabeno , phyllis.stabeno@noaa.gov, NOAA Pacific Marine Environmental Laboratory Michael Sigler , mikesigler8@gmail.com, Shoals Marine Lab Calvin Mordy , calvin.w.mordy@noaa.gov, CICOES, University of Washington, Seattle, WA, United States The Chukchi Sea is a shallow sea that connects the Bering Sea to the Beaufort Sea. Water is transported northward through the Bering Strait, into the Chukchi Sea and out to the Beaufort Sea primarily through Barrow and Herald Canyon. There are generally three distinct water masses in the Chukchi Sea: the Alaskan Coastal Water (ACW) which is warmer, fresher and is derived from river runoff, the Anadyr Water which is colder and saltier, and lastly the Bering Sea Water which is an intermediate composition. The warmer, fresher ACW is carried by the Alaskan Coastal Current (ACC). Understanding the transport of these water masses is important to understanding seasonal oceanography that impacts local Chukchi ecosystems. The strength and timing of ACC in the late summer months and its water is known to impact ice algal communities, as well as other key species. We analyzed data from ADCP moorings, CTD and nutrient samples over a 9-year period (2011-2020) to quantify the volume of ACW across the DBO3 transect off Point Hope. Cross sectional area of ACW varies over the 9 years from 2.2 x 10^5 to 1.2 x 10^6 m^2. Currents (from ADCPs) are well correlated with the winds. Strong southward winds over a period of a few days, weaken the northward velocity of the ACC and cause a divergence (spreading out) of the ACW due to upwelling. The occurrence of warmer, nutrient- poor water offshore may be the result of melt water or upwelling that splits the ACW and pushes this water offshore. This water is no longer a part of the well-formed Alaskan Coastal Current. We quantify the range of variability in salt (including nutrients) and temperature in the ACW during the last 9 years during late summer and early fall. This finding is important to understand mixing dynamics and seawater chemistry that impacts the rapidly changing ecosystem in the Chukchi Sea. Further analysis is underway to quantify the change in the volume of Alaskan Coastal Water northward due to southward wind events that cause upwelling, and assess nutrient variability in ACW.
Alaska Marine Science Symposium 2023 118
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