Arctic Ocean water mass transformation in S-T coordinates
(English)Article in journal (Refereed) Submitted
In this paper, water mass transformations in the Arctic Ocean are studied using a new salinity-temperature (S–T) framework, which builds on earlier work by Walin (1977, 1982). The framework, presented in Hieronymus et al. (2014), allows the water mass transformations to be succinctly quantified by computing the surface and internal diffusive fluxes in S–T coordinates. Here, we show how the method can be applied to a specific oceanic region, in our case the Arctic Ocean, by including the advective exchange of water masses across the interior boundaries of the region. Based on a simulation with a global ocean-circulation model, we examine the importance of various parameterized mixing processes and surface fluxes for the transformation of water across isohaline and isothermal surfaces in the Arctic Ocean. The model-based results reveal a broadly realistic Arctic Ocean where the inflowing Atlantic and Pacific waters are primarily cooled and freshened before exiting back to the North Atlantic. In the model, the water mass transformation in the T-direction is primarily accomplished by the surface heat flux. However, the surface freshwater flux plays a minor role for the transformation of water towards lower salinities, which is mainly driven by down- gradient mixing of salt in the interior ocean. Near the freezing line, the seasonal melt and growth of sea ice influences the transformation pattern.
Oceanography, Hydrology, Water Resources
Research subject Atmospheric Sciences and Oceanography
IdentifiersURN: urn:nbn:se:su:diva-107562OAI: oai:DiVA.org:su-107562DiVA: diva2:748443