Estimation of Atlantic Water transit times in East Greenland fjords using a 233U-236U tracer approach

Water mass composition and transit times of outflowing waters from the Arctic Ocean can reflect changes polar climate ocean circulation upstream. In this study we apply a novel approach using anthropogenic uranium tracers ( 233 U 236 U), combined with salinity, nutrients (nitrate phosphate) to estimate Atlantic passing through into East Greenland fjords. Polar Surface (PSW, typically found in surface ~150 m fjords) dominant source is European reprocessing plants (63%) while (AAW, directly below PSW these it much less (26%) signal dominated by global fallout contribution. Here isolate U/ ratios use temporal development discharges for entering exiting as either or AAW on Shelf. PSW, which flows fjords shelf, has time between 6 14 years entrance (Barents Sea Opening, 74°N, 19°E). The AAW, entrained upwelling subglacial discharge inner parts fjords, order 24–25 since Barents Sea. findings indicate potential U- trace Ocean. method offers independent estimates compare models indicates lag documented recent change properties water leaving upstream processes contributing changes. • Novel dominates (63%). Much contribution Transit 6–14 years.