Antarctic Circumpolar Current (ACC)

Assembled from 61 blocks · 2 evidence · 88 related

1. Story
2. The largest current on Earth and the only one that circles the globe without meeting a coastline. Driven by the strongest sustained westerlies on the planet and unblocked by land, it runs eastward around Antarctica and connects the Atlantic, Pacific and Indian basins into one system — which is what makes a global overturning circuit possible at all. Continuous measurements in Drake Passage from 2007 to 2011 gave a mean transport of 173.3 Sv, the sum of a mean barotropic component of 45.6 ± 8.9 Sv and a baroclinic component of 127.7 Sv relative to zero at the seafloor. That total is about 30 per cent larger than the 134 Sv figure that had served as the benchmark for climate models for decades.
3. Knowledge
4. Atlantic Meridional Overturning Circulation (AMOC)
5. Antarctic Circumpolar Current (ACC)
6. Southern Ocean
7. Drake Passage
8. Connections
9. Antarctica
10. Antarctic Polar Front (Antarctic Convergence)
11. Atlantic Meridional Overturning Circulation (AMOC)
12. Drake Passage
13. Southern Ocean
14. Drake Passage
15. A circumpolar current becomes possible
16. Drake Passage is measured and the ACC turns out to be larger
17. Gulf Stream
18. Thermohaline Circulation
19. Antarctic Circumpolar Current (ACC)
20. North Atlantic Deep Water (NADW)
21. RAPID-MOCHA-WBTS Array at 26.5°N
22. Overturning in the Subpolar North Atlantic Program (OSNAP)
23. Meridional Ocean Heat Transport
24. The RAPID array begins continuous AMOC measurement at 26.5°N
25. OSNAP moves the engine room out of the Labrador Sea
26. IPCC AR6 assesses AMOC decline as very likely and collapse as unlikely this century
27. A statistical early-warning analysis puts an AMOC collapse mid-century
28. A physics-based early warning signal is proposed
29. Twenty-two years of continuous AMOC observation
30. Antarctic Circumpolar Current (ACC)
31. Antarctic Circumpolar Current (ACC)
32. A circumpolar current becomes possible
33. Drake Passage is measured and the ACC turns out to be larger
34. Antarctic Blue Whale (B. m. intermedia)
35. Antarctic Summer Feeding Migration
36. South Georgia
37. Southern Ocean Whale Sanctuary
38. Seasonal Krill Aggregation
39. The factory ship Lancing takes a stern slipway south
40. The Antarctic blue whale catch reaches its all-time peak
41. The Southern Ocean Whale Sanctuary is adopted
42. Dedicated Antarctic Blue Whale Project voyages
43. Baleen whale consumption is re-measured, and the krill paradox sharpens
44. The only published Antarctic blue whale satellite tracks are released as data
45. Antarctic Krill (Euphausia superba)
46. Arctic Tern (Sterna paradisaea)
47. CCAMLR is agreed at Canberra
48. A long-term decline in krill density is linked to winter sea ice
49. CCAMLR adopts the Ross Sea marine protected area
50. Antarctic sea ice reaches a record low, a year after the previous one
51. Antarctic Circumpolar Current (ACC)
52. Antarctica
53. Thermohaline Circulation
54. North Atlantic — Grand Banks approaches
55. Weddell Sea
56. A circumpolar current becomes possible
57. Antarctic meltwater is projected to slow the abyssal cell
58. A physics-based early warning signal is proposed
59. Evidence
60. Continuous Drake Passage observations from 2007 to 2011 give a mean ACC transport of 173.3 Sv — barotropic 45.6 ± 8.9 Sv plus baroclinic 127.7 Sv relative to zero at the seafloor — about 30 per cent above the canonical benchmark value. Figures taken from search summaries of the abstract; the article is on a blocked publisher domain.
61. The timing of ACC onset is contested: this paper places the modern ACC in the late Miocene, while other studies place onset near the Eocene–Oligocene transition (~34 Ma), at ~31 Ma from foraminiferal and neodymium evidence, at ~30 Ma from Tasmanian gateway–westerly alignment, and at ~24 Ma from flow-speed and water-mass homogeneity records. The disagreement is stated, not resolved; none of the papers was fetched.