Warming of Atlantic Water in three west Spitsbergen fjords: recent patterns and century-long trends

• Published in: Polar Research
• Main Authors: Bloshkina, Ekaterina V., Pavlov, Alexey K., Filchuk, Kirill
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norwegian Polar Institute 2021
• Subjects: Atlantification; Svalbard; Isfjorden; Grønfjorden; water masses; climate change; Billefjorden; Isfjord*; Polar Research; Spitsbergen
• Online Access: https://polarresearch.net/index.php/polar/article/view/5392; https://doi.org/10.33265/polar.v40.5392

We investigated the recent warming of summer Atlantic Water in relation to the century-long trends in maximum temperature in three west Spitsbergen fjords: Isfjorden, Grønfjorden and Billefjorden. On the basis of repeated along-fjord transects in late summer 2003–2019, we found that the warming has been pronounced not only in the outer but also in the inner domain of Isfjorden, where the presence of waters of Atlantic origin was registered more frequently after 2011 compared to early 2000s. Furthermore, Atlantic waters occurred more frequently in the bottom layers in the inner part of the fjord. In all the investigated fjords, the year 2014 was the warmest and saltiest during the period 2003–2019, which is consistent with previous reports for other west Spitsbergen fjords. In 2014, the mean temperature and salinity in Isfjorden and Grønfjorden exceeded 4.9 °C and 34.7 (in Billefjorden, 4.0 °C and 34.67, respectively). With the new data for 2010–19, we extended the time-series of maximum Atlantic Water temperature in Isfjorden and Grønfjorden, covering 1912–2009, reported previously by Pavlov et al. 2013. For the period 1912–2019, the average long-term trend of Atlantic Water maximum temperature is 0.25 °C/decade and 0.22 °C/decade in the outer part of Isfjorden and Grønfjorden, respectively. In the first two decades of the 21st century, the warming trend is steeper compared to the 20th century, 0.78 °C/decade in Isfjorden and 0.56 °C/decade in Grønfjorden, highlighting the strength of the ongoing ‘Atlantification’ of west Spitsbergen fjords.