Morrison A K, Hogg A McC, England M H, Spence P
Research School of Earth Sciences and ARC Centre of Excellence for Climate Extremes, Australian National University, Canberra, Australia.
Climate Change Research Centre and ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, Australia.
Sci Adv. 2020 May 1;6(18):eaav2516. doi: 10.1126/sciadv.aav2516. eCollection 2020 May.
Poleward transport of warm Circumpolar Deep Water (CDW) has been linked to melting of Antarctic ice shelves. However, even the steady-state spatial distribution and mechanisms of CDW transport remain poorly understood. Using a global, eddying ocean model, we explore the relationship between the cross-slope transports of CDW and descending Dense Shelf Water (DSW). We find large spatial variability in CDW heat and volume transport around Antarctica, with substantially enhanced flow where DSW descends in canyons. The CDW and DSW transports are highly spatially correlated within ~20 km and temporally correlated on subdaily time scales. Focusing on the Ross Sea, we show that the relationship is driven by pulses of overflowing DSW lowering sea surface height, leading to net onshore CDW transport. The majority of simulated onshore CDW transport is concentrated in cold-water regions, rather than warm-water regions, with potential implications for ice-ocean interactions and global sea level rise.
温暖的绕极深层水（CDW）向极地的输运与南极冰架的融化有关。然而，即使是CDW输运的稳态空间分布及其机制仍知之甚少。利用一个全球涡旋海洋模型，我们探究了CDW的跨坡输运与下沉的致密陆架水（DSW）之间的关系。我们发现，南极洲周围CDW的热量和体积输运存在很大的空间变异性，在DSW于峡谷中下沉的地方，水流显著增强。CDW和DSW的输运在约20公里范围内具有高度的空间相关性，并且在亚日时间尺度上具有时间相关性。以罗斯海为例，我们表明这种关系是由DSW溢出脉冲降低海面高度驱动的，从而导致CDW的净向岸输运。模拟的大部分CDW向岸输运集中在冷水区域，而非温水区域，这对冰 - 海洋相互作用和全球海平面上升可能具有影响。
