Articles | Volume 18, issue 4
Ocean Sci., 18, 953–978, 2022
Ocean Sci., 18, 953–978, 2022
Research article
06 Jul 2022
Research article | 06 Jul 2022

Causes of the 2015 North Atlantic cold anomaly in a global state estimate

Rachael N. C. Sanders et al.

Data sets

Synopsis of the ECCO central production global ocean and sea-ice state estimate ECCO Consortium, I. Fukumori, O. Wang, I. Fenty, G. Forget, P. Heimbach, and R. Ponte

Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century ( N. Rayner, D. E. Parker, E. Horton, C. K. Folland, L. V. Alexander, D. Rowell, E. Kent, and A. Kaplan

EN.4.2.2 data Met Office Hadley Centre

Short summary
In 2015, record low temperatures were observed in the North Atlantic. Using an ocean model, we show that surface heat loss in December 2013 caused 75 % of the initial cooling before this "cold blob" was trapped below the surface. The following summer, the cold blob re-emerged due to a strong temperature difference between the surface ocean and below, driving vertical diffusion of heat. Lower than average surface warming then led to the coldest temperature anomalies in August 2015.