|
ИСТИНА |
Войти в систему Регистрация |
ИСТИНА ИНХС РАН |
||
Modelled response of Arctic and North Atlantic thermohaline structure and circulation to the prolonged unidirectional atmospheric forcing over the Arctic Oceanстатья
- Авторы: Ivanov V.V., Gusev A., Diansky N., Sukhonos P.
- Журнал: Climate Dynamics
- Год издания: 2024
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- DOI: 10.1007/s00382-024-07239-6
- Аннотация: In this model study, we address the probability of rapid reorganization of thermohaline structure and circulation in the Arctic (AO) and North Atlantic (NA) oceans under the prolonged unidirectional atmospheric forcing over the AO. The relevance of such investigation is dictated by the presence of huge volume of surplus fresh water accumulated in the Beaufort Gyre (BG) of the Canada Basin for the past 30 years due to extremal sea ice melting and increased river runoff. In hypothetical case of rapid release to the NA, this fresh water volume may at least cause strong salinity anomaly similar to the Great Salinity Anomaly in the 1970s. Taking into account that the subpolar NA is the key locus of the deep water formation feeding the southward branch of the Atlantic Meridional Overturning Circulation (AMOC), the excess freshening at the ocean surface may negatively affect the AMOC intensity. To check up the validity of this hypothesis, we carried out the two idealized model experiments with opposite atmospheric forcings over the AO: the so-called “cyclonic” one, which favours intensive NA–AO water exchange, and the “anticyclonic” one, which impedes such an exchange. We chose the two actual years with extremal forcings (1989 as a cyclonic one, and 2004 as an anticyclonic one) and artificially applied them for the 10-year period assuming that such a duration is at the margin of physical realism. Our major finding, within the limitations of numerical experiments on the OGCM (Ocean General Circulation Model) INMOM (Institute of Numerical Mathematics Ocean Model), shows that anomalously long preservation of “cyclonic” forcing over the AO is able to substantially rearrange salinity in the upper ocean layer. However, it may not trigger massive “instant” outflow of freshwater through the Fram and Denmark Straits, since a large portion of accumulated in the BG freshwater spreads around the AO following the surface circulation pattern without reaching the Fram Strait. However, the tendency of the upper ocean layer freshening in the subpolar NA due to freshwater flushing from the AO is confirmed.
- Добавил в систему: Иванов Владимир Владимирович