Tyler D. Hennon
Daniel Monson
Robert M. Suryan
Rob W. Cambell
Steven J. Baird
Kristine Holderied
Thomas J. Weingartner
Seth L. Danielson
2022
<div id="abstracts" class="Abstracts u-font-serif"><div id="abs0010" class="abstract author" lang="en"><div id="abssec0010"><p id="abspara0010">Surface and subsurface moored buoy, ship-based, remotely sensed, and reanalysis datasets are used to investigate thermal variability of northern Gulf of Alaska (NGA) nearshore, coastal, and offshore waters over synoptic to century-long time scales. NGA sea surface temperature (SST) showed a larger positive trend of 0.22 ± 0.10 °C per decade over 1970–2021 compared to 0.10 ± 0.03 °C per decade over 1900–2021. Over synoptic time scales, SST covariance between two stations is small (<10%) when separation exceeds 100 km, while stations separated by 500 km retain 50% of their co-variability for seasonal and longer fluctuations. Relative to<span> </span><i>in situ</i><span> </span>sensor data, remotely sensed SST data has limited accuracy in some NGA settings, capturing 60–70% of the daily SST anomaly in coastal and offshore waters, but often <25% nearshore. North Pacific and NGA leading modes of SST variability leave 25–50% of monthly variance unresolved. Analysis of the 2014–2016 Pacific marine heatwave shows that NGA coastal surface temperatures warmed contemporaneously with offshore waters through 2013, but deep inner shelf waters (200–250 m) exhibited delayed warming. Offshore surface waters cooled from 2014 to 2016, while shelf waters continued to warm from the combined effects of local air-sea and advective heat fluxes. We find that annually averaged Sitka air temperature is a leading predictor (r<sup>2</sup> = 0.37, p < 0.05) for following-year NGA coastal water column temperature. Our results can inform future environmental monitoring designs, assist forward-looking projections of marine conditions, and show the importance of<span> </span><i>in situ</i><span> </span>measurements for nearshore studies that require knowledge of thermal conditions over time scales of days and weeks.</p></div></div></div>
application/pdf
10.1016/j.dsr2.2022.105155
en
Elsevier
Temperature variations in the northern Gulf of Alaska across synoptic to century-long time scales
article