AON observations in the Eurasian and Makarov Basins target changes in the Arctic Ocean

Abstract:

The pan-Arctic boundary current provides the largest input of water, heat, and salt into the Arctic Ocean. Recent observations captured strong changes in the Eurasian and Makarov basins (EMB); understanding the transition requires tracing the intensity of this major subsurface transport system. Responding to urgent needs for a long-term observation system for understanding rapid high-latitude climate change, an EMB observational network is implemented as an element of the Arctic Observing Network (AON). The overarching goal of this AON program is to compile a cohesive picture of the state and transformations of water masses (particularly, Atlantic Water, AW) in the EMB. NABOS (=Nansen and Amundsen Basins Observational System) was the predecessor of this AON program. Observations provided by the program were critical for understanding the large-scale structure and temporal variability of an oceanic boundary current. Fourteen years long observations were instrumental for documenting all stages of the AW warming providing evidence for the anomalous state of the ocean in the 2000s. For example, the prevailing anticyclonic circulation in 2008-10 over the central Laptev Sea slope was documented — a deviation from the classical shallow-to-right circulation paradigm. This program naturally complements the existing AON infrastructure in a synergistic way working hand-in-hand with other elements of the AON, which is vital for interpreting and assessing polar climate change.