An inverse modeling study of circulation in the Eastern Bering Sea during 2007–2010

Abstract

A two‐way nested 4d‐variational data assimilation system is implemented in the Eastern Bering Sea (EBS) to investigate changes in circulation and thermodynamic state for a 3.8 year period. Assimilated observations include data from 19 moorings deployed on the shelf and in the Bering Strait, 1705 hydrographic stations occupied during eight surveys, and remotely sensed sea surface temperature and sea surface height (SSH) data. Validation of the presented 4dVar reanalysis against the output of two sequential data‐assimilative systems (the Bering Ecosystem Study ice‐ocean Modeling and Assimilation System (BESTMAS) and the Arctic Cap Nowcast‐Forecast System (ACNFS)) has shown that the product is more consistent with the observed transports in the Bering Strait and in the EBS interior both in terms of their magnitude and time variability. Analysis of the data‐optimized solution quantifies a sequence of wind‐forced events that resulted in the anomalous heat and freshwater transports through the Bering Strait, including a 28 day long flow reversal that occurred in November 2009 and carried Siberian Coastal Current water down to the Gulf of Anadyr. Lagrangian study of the Arctic‐bound Pacific waters indicates the extreme importance of the cross‐shelf exchange along the path of the Bering Slope Current and quantifies the spectrum of residence times for the waters entering EBS through Unimak Pass and through Aleutian passages. Residence times in the EBS cold pool are diagnosed to be 2–3 times longer than those in the surrounding waters.

Forum for Arctic Modeling and Observational Synthesis (FAMOS): Past, current, and future activities

“…[], 37— Panteleev et al . [], 38—B. Rudels (Arctic Ocean Stability: The effects of local cooling, oceanic heat transport, freshwater input and sea ice melt with special emphasis on the Nansen Basin, J. Geophys.…”

“…Finally on the topic of ocean circulation, Panteleev et al . [] present a comprehensive study in this issue of the Bering Sea circulation; their study is based on the Four‐Dimensional Variational Data Assimilation (4‐DVAR) technique integrated with satellite sea‐surface temperature and sea‐surface height data, plus extensive in situ mooring and hydrographic station observations. Specifically, the Bering Strait water transport anomalies for two wind forcing events were scrutinized using Lagrangian analysis of water particles.…”