On the geostrophic system of the Chukchi and Beaufort Seas from multi-mission satellite altimetry

Satellite radar altimetry provides basin-wide observations of sea surface height in the rapidly changing Arctic Ocean, where harsh conditions and remote access limit in-situ measurements. In this study, we developed and analyzed a dataset of dynamic ocean topography (DOT) and geostrophic currents in the Pacific Arctic, based on multi-mission radar altimetry (cross-calibrated Envisat, SARAL, and CryoSat-2). The use of the state-of-the-art lead-detection algorithms and a novel approach for sea surface height retrieval in ice-covered regions enabled an improved temporal and spatial resolution (10d/8km) over 2002–2024. Careful processing, along with validation against mooring data and comparison with the drifter data, allowed to observe not only interannual and seasonal, but also reliable synoptic variability of the sea level and associated geostrophic flow in the Chukchi and Beaufort Seas. We associate the eastward geostrophic flow along the Alaskan coast with the surface signature of the Beaufort Shelfbreak Jet, known to be surface-intensified from mid-summer to early autumn. Stronger eastward flow develops in the absence of northerly winds, opposing the flow, coinciding with the periods of the weaker anticyclonic circulation of the Beaufort Gyre (BG). Such conditions were more common and persisted later into autumn over the last decade, with pronounced October peaks (2012–2016), coupled with the smaller area and lower DOT of the BG. In response to shifted atmospheric patterns, the eastward geostrophic flow has been extended further towards the Canadian archipelago and observed later into the season, e.g., even in November 2012. In this study, we showcase the synoptic-scale response of geostrophic circulation features in the region to varying atmospheric conditions.     «

Satellite radar altimetry provides basin-wide observations of sea surface height in the rapidly changing Arctic Ocean, where harsh conditions and remote access limit in-situ measurements. In this study, we developed and analyzed a dataset of dynamic ocean topography (DOT) and geostrophic currents in the Pacific Arctic, based on multi-mission radar altimetry (cross-calibrated Envisat, SARAL, and CryoSat-2). The use of the state-of-the-art lead-detection algorithms and a novel approach for sea sur...     »