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DOI | 10.1007/s00382-019-04758-5 |
Impact of freshwater release in the Mediterranean Sea on the North Atlantic climate | |
Swingedouw, Didier1; Colin, Christophe2; Eynaud, Frederique1; Ayache, Mohamed1; Zaragosi, Sebastien1 | |
2019-10-01 | |
发表期刊 | CLIMATE DYNAMICS
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ISSN | 0930-7575 |
EISSN | 1432-0894 |
出版年 | 2019 |
卷号 | 53页码:3893-3915 |
文章类型 | Article |
语种 | 英语 |
国家 | France |
英文摘要 | Sediment cores from the Mediterranean Sea have evidenced several periods of Sapropel deposition, which can be explained by events of anoxic bottom conditions. An explanation for such events calls for a very stratified sea, possibly related with freshwater input through increased precipitations and runoff discharges. It has been suggested that such a stratified Mediterranean Sea may in turn weaken the Atlantic meridional overturning circulation (AMOC) through changes in the Mediterranean overflow water (MOW). Nevertheless, models used to establish this result were relatively simple and the mechanisms leading to such an impact remained elusive. To improve on those previous studies, we analyse the impact of different freshwater releases with rates of 0.2, 0.1, 0.05 and 0.02 Sv (1 Sv = 106 -m3/s) in the Mediterranean Sea using the IPSL-CM5A-LR model in a few multi-centennial simulations. We focus the analysis on the impact of a decrease in the MOW on the large-scale Atlantic circulation. We find a consistent change in horizontal currents in the upper Atlantic Ocean in all simulations in the first century, with a large enhancement of the northward current west of Rockall in the northeast Atlantic. Concerning the AMOC response, we identify three different processes that impact its fate. The first is related to changes in geostrophic currents at depth induced by the disappearance of the MOW, which tends to weaken the AMOC. On the contrary, the second enhances the AMOC and is associated with the increase in northward currents in the horizontal upper circulation. The last process is due to the spread of surface freshwater anomalies out of the Mediterranean Sea that freshens the North Atlantic convection sites and weakens the AMOC. Depending on the rate of the freshwater release, the strength and balance of these three processes are different. For rates larger than 0.05 Sv, we observe a strong reduction of the AMOC, while for lower rates, we notice an enhancement in the upper cell. The climatic response follows that of the upper AMOC with a warming of the North Atlantic for rates lower than 0.05 Sv and a cooling for higher rates. Given that past estimates of freshwater release in the Mediterranean Sea indicate rates lower than 0.05 Sv, we argue that Sapropel events may have enhanced of the upper AMOC and warmed of the North Atlantic. |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000489753900011 |
WOS关键词 | AZORES CURRENT ; OUTFLOW WATER ; LABRADOR SEA ; ICE MODEL ; SAPROPEL ; OCEAN ; CIRCULATION ; OVERFLOW ; SURFACE ; CADIZ |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/187200 |
专题 | 气候变化 |
作者单位 | 1.Univ Bordeaux, OASU, EPOC, CNRS,UMR 5805, Allee Geoffroy St Hilaire, F-33615 Pessac, France; 2.Univ Paris Saclay, Univ Paris Sud, Lab GEOsci Paris Sud GEOPS, CNRS,UMR 8148, Batiment 504, F-91405 Orsay, France |
推荐引用方式 GB/T 7714 | Swingedouw, Didier,Colin, Christophe,Eynaud, Frederique,et al. Impact of freshwater release in the Mediterranean Sea on the North Atlantic climate[J]. CLIMATE DYNAMICS,2019,53:3893-3915. |
APA | Swingedouw, Didier,Colin, Christophe,Eynaud, Frederique,Ayache, Mohamed,&Zaragosi, Sebastien.(2019).Impact of freshwater release in the Mediterranean Sea on the North Atlantic climate.CLIMATE DYNAMICS,53,3893-3915. |
MLA | Swingedouw, Didier,et al."Impact of freshwater release in the Mediterranean Sea on the North Atlantic climate".CLIMATE DYNAMICS 53(2019):3893-3915. |
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