Tiger, unwittingly find themselves in a magical pond where fish get powers when they reach adulthood. However, it does highlight the need for climate researchers to consider the effects of both short-term interannual variability and longer-term mechanisms to understand the implications of a warmer future reducing, or even collapsing, AABW formation.In the animated series Weird Waters (now streaming on Peacock!), two fishy friends, BZ and I.M. It also does not account for seasonal variations in meltwater input, which freshens saline water, or ice shelf cavities. While this research shows a correlation between wind and DSW (subsequently AABW) formation, the scientists do note that the effect of tides have not been included within the simulations, which are known to contribute to a reduction in AABW formation, this being a 10% and 30% decrease in the Weddell and Ross Seas respectively. This occurred in the Weddell Sea when strong surface water mass transport in 1962, 19 led to enhanced AABW formation during the 1960s, 1980s and from the late 1990s to mid 2000s. When there are particularly strong downwelling events of dense and saline DSW, then the models show higher AABW export from the region for up to 10 years thereafter. Within the Ross Sea, the researchers found that with greater sea ice formation, the flux of DSW into AABW increased, though this wasn't consistent across all four regions. Seasonality is also shown to be a factor in AABW formation and transport, with austral winter (occurring in the southern hemisphere June to August) seeing the greatest downwelling of surface waters, compared to none or very little in the summer.ĭuring sea ice formation, brine is rejected into the ocean, increasing salinity and contributing to surface waters being transformed to depth. Therefore, as sea ice grows, more salt is expelled into the oceans, increasing the amount available to form dense, saline AABW.įour Antarctic regions showing the transport of surface water to depth (red colour scale), as well as the flow of tracer dyes (green colour scale) away from them, indicating AABW currents. This creates polynyas, which are exposed to the full force of cold Antarctic air, thus encouraging sea ice formation at a much faster rate. The former scenario was found to have strong impacts on ocean circulation for up to a decade thereafter, while the latter results from the narrower East Antarctic shelf causing rapid export of Deep Sea Water (DSW) that prevents accumulation at depth.Ī posited cause of this increased AABW formation from the Weddell and Ross Seas is weaker polar easterly winds, or even complete reversal to westerlies, which reduce the amount of sea ice being transported into the area, therefore leaving more open ocean. 2023ĪABW reservoir export from the Weddell and Ross Seas can last up to two years, while for Prydz Bay and the Adélie Coast it is less than a year. Map of the four regions of Antarctica featured in this study, with darker colours indicating peak areas of surface water being transported to depth. ![]() These models, reported in the Journal of Geophysical Research: Oceans, consider how changes in sea ice transport, melting of land-based ice and coastal winds impact AABW. ![]() Researchers at the University of New South Wales, Australia, simulated the formation and migration of AABW over a 60-year period from four regions around Antarctica (the Weddell and Ross Seas, Prydz Bay and the Adélie Coast) based upon ocean-sea ice models. This salt concentrates in the ocean, making the sea water denser so that it sinks, drawing warmer and more buoyant offshore sea water to the area in a continuous cycle known as thermohaline circulation. It also affects the global climate and sea level rise, which impacts coastal communities.ĪABW forms as a consequence of cold polar winds bringing sea ice into the region, the formation of which expels salt into the ocean (sea ice has a salinity of approximately 5‰, compared to 34.5‰ of the surrounding sea water). This has consequences for ocean temperatures, ventilation and nutrient distribution to the surface, affecting marine ecosystems and the diverse organisms they support. However, in recent decades AABW has become warmer, less saline and has declined in volume.
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