Transport and thermohaline variability in Barrow Canyon on the Northeastern Chukchi Sea Shelf

We used a 5 year time series of transport, temperature, and salinity from moorings at the head of Barrow Canyon to describe seasonal variations and construct a 37 year transport hindcast. The latter was developed from summer/winter regressions of transport against Bering-Chukchi winds. Seasonally, the regressions differ due to baroclinicity, stratification, spatial, and seasonal variations in winds and/or the surface drag coefficients. The climatological annual cycle consists of summer downcanyon (positive and toward the Arctic Ocean) transport of approximate to 0.45 Sv of warm, freshwaters; fall (October-December) upcanyon transport of approximate to-0.1 Sv of cooler, saltier waters; and negligible net winter (January-April) mass transport when shelf waters are saline and near-freezing. Fall upcanyon transports may modulate shelf freezeup, and negligible winter transports could influence winter water properties. Transport variability is largest in fall and winter. Daily transport probability density functions are negatively skewed in all seasons and seasonal variations in kurtosis are a function of transport event durations. The latter may have consequences for shelf-basin exchanges. The climatology implies that the Chukchi shelf circulation reorganizes annually: in summer approximate to 40% of the summer Bering Strait inflow leaves the shelf via Barrow Canyon, but from fall through winter all of it exits via the western Chukchi or Central Channel. We estimate a mean transport of approximate to 0.2 Sv; approximate to 50% less than estimates at the mouth of the canyon. Transport discrepancies may be due to inflows from the Beaufort shelf and the Chukchi shelfbreak, with the latter entering the western side of the canyon.