Winter Arctic Outflow Winds Cause Upper Ocean Cooling and Reoxygenation in a Temperate Canadian Fjord

Arctic outflow winds bring cold air from the continent to the coastline through mountain passes. Using observational data and a 2-D model, we show that a February 2019 outflow event caused the upper 100 m in Bute Inlet, British Columbia (within the traditional territory of the Homalco Nation) to cool up to 1.9 & DEG;C and gain up to 4.1 mLL(-1) of oxygen. The cold, oxygenated water persisted for almost 1 year within the 1,023-1,023.5 kgm(-3) isopycnal range (& SIM;50-150 m). Atmospheric (from 1929 to 2022) and oceanographic (from 1951 to 2022) data showed a statistically significant relationship between continental air temperature at Tatlayoko Lake and temperature and oxygen in Bute Inlet. This local mechanism that counters some effects of climate change could create a biological refugium as surrounding waters warm and lose oxygen at a faster rate. The number of outflow events decreased from 1951 to 2018, and increased since.

Automated summary

Using observational data and a 2-D model, this study demonstrates the impact of an Arctic outflow event in February 2019 on water temperature and oxygen levels in Bute Inlet, British Columbia. The findings suggest that this local mechanism might counteract the effects of climate change and create a refuge for marine life. Moreover, the frequency of outflow events has shown a recent increase.