Evaporative dense water formation and cross‐shelf exchange over the northwest Australian inner shelf

摘要

High‐resolution surveys of oceanographic and atmospheric conditions made during the\udwinter over the inner shelf off northwest Australia are used to examine the coastal ocean\udresponse to large outgoing heat and freshwater fluxes. Relatively cool, low‐humidity air\udblows off the Australian continent out over the tropical continental shelf, resulting in a large\udmean latent heat flux (−177Wm−2) that overwhelms insolation and, along with the outgoing\udlong‐wave radiation, results in substantial net cooling (−105 W m−2) and evaporative\udfreshwater flux (0.6 cm d−1). The inner shelf is characterized by increasingly cool, salty,\udand dense waters onshore, with a strong front near the 25 m isobath. The front is evident\udin satellite sea surface temperature (SST) imagery along the majority of the northwest\udAustralian shelf, exhibiting a complex filamentary and eddy structure. Cross‐shelf buoyancy\udfluxes estimated from the mean, two‐dimensional heat and salt budgets are comparable\udto parameterizations of cross‐shelf eddy driven fluxes; however, the same fluxes can be\udachieved by cross‐shelf transports in the bottom boundary layer of about 0.5 m2 s−1 (and an\udoverlying return flow).