Variations of the Pacific-Origin Summer Waters in the Chukchi Borderland, Arctic Ocean

Abstract:

We have conducted intensive Arctic summertime surveys in recent 5 years to examine temporal variations and spatial distributions of the Pacific-origin Summer Water (PSW) in the Chukchi Borderland (CBL), Arctic Ocean. With the Korean icebreaker Araon, these expeditions lasted for 21 days in 2011, 45 days in 2012, 13 days in 2013, and 25 days in 2014, mostly July to August. It is understood that heat transport of the PSW to CBL is one of the key processes to comprehend the rapid sea ice reduction and changes in water column structure in the Pacific sector of the Arctic Ocean. We present recent features of PSW’s variations identified from our Arctic cruise data using CTD/XCTD, LADCP, and other measurements. In 2011 summer, the PSW appeared to exist in the eastern flank of the Chukchi Plateau and its signal diminished gradually toward the west. In 2012 summer, the PSW tended to mainly pass through the vicinity of the Northwind Ridge and extended toward the west. In 2013 summer, the PSW with 0.29° C and 30.68 psu was found in the center of the Chukchi Plateau and its layer deepened slightly toward the east. During the cruises in 2011, 2012, and 2013, the PSW was identified in the west of 175° W where it had never been observed previously. In addition, how the spreading of PSW’s pathway and distribution of temperature maximum layer do have an influence on rapid sea ice retreat will be discussed.