The Agulhas Return Current (ARC) is an ocean current in the South Indian Ocean. The ARC contributes to the water exchange between oceans by forming a link between the South Atlantic Current and the South Indian Ocean Current.[1] It can reach velocities of up to 4 knots (7.4 km/h; 4.6 mph) and is therefore popular among participants in trans-oceanic sailing races.[2]
The Agulhas Return Current (ARC) meanders east from the southern tip of Africa
The Agulhas Current follows the continental shelf of the African east-coast, pass through the Agulhas Passage until it leaves the Agulhas Bank and reaches the Agulhas Basin south of South Africa. From there it retroflects almost completely back into the south Indian Ocean as the ARC, and only a smaller part, known as Agulhas leakage, is shed into the South Atlantic.[3]
The water mass loses a lot of heat at the Agulhas Retroflection, up to 200 W/m3 (0.0076 hp/cu ft), while evaporation and precipitation change the composition of the upper layers. The ARC, therefore, has another composition than the Agulhas Current proper.[3] It also loses velocity from 110–75 cm/s (43–30 in/s) and volume transport from 70 to 54 million m³/s. Furthermore, all traces of Indian Tropical Surface Water are gone.[4]
Having left the retroflection, the ARC meanders east between 36°S and 41°S.[5] These meanders were described as Rossby waves in 1970[6] and are known to shed cold eddies equatorward and enhance the primary productivity at the Subtropical Front.[7] The ARC makes a large, quasi-permanent northward meander around the Agulhas Plateau after which it loses more velocity and volume by leakage into the South Indian subtropical gyre. Over the Crozet Basin the last remnants of the ARC are gone.[4] As it enters the Crozet Basin at 53°E, the transport of the ARC is 35 Sv, most of which is recirculated northward before reaching the Kerguelen-Amsterdam Passage.[8] The current east of the Crozet Basin, at 66°E-70°E, is called the South Indian Ocean Current and lacks the distinctive features of the ARC.[4]
Boebel, O.; Rossby, T.; Lutjeharms, J.; Zenk, W.; Barron, C. (2003). "Path and variability of the Agulhas Return Current" (PDF). Deep-Sea Research Part II: Topical Studies in Oceanography. 50 (1): 35–56. doi:10.1016/S0967-0645(02)00377-6. Retrieved 15 May 2015.
Harris, T. F. W. (1970). "Planetary-type Waves in the South West Indian Ocean". Nature. 227 (5262): 1043–1044. doi:10.1038/2271043a0. S2CID 4166656.
Lutjeharms, J. R. E.; Ansorge, I. J. (2001). "The Agulhas return current" (PDF). Journal of Marine Systems. 30 (1): 115–138. doi:10.1016/s0924-7963(01)00041-0. Retrieved 15 May 2015.
Lutjeharms, J.; Ansorge, I.; Gründlinch, M.; Ballegooyen, R., van; Weeks, C.; Machu, E.; Boebel, O. (2004). "Comment on "New Global Drifter Data Set Available"". Eos, Transactions American Geophysical Union. 85 (19): 188. Bibcode:2004EOSTr..85..188K. doi:10.1029/2004EO190010.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Park, Y.-H.; Gamberoni, L.; Charriaud, E. (1993). "Frontal structure, water masses, and circulation in the Crozet Basin". Journal of Geophysical Research. 98 (C7): 12361–12385. Bibcode:1993JGR....9812361P. doi:10.1029/93JC00938.
Rouault, M.; Penven, P.; Pohl, B. (2009). "Warming in the Agulhas Current system since the 1980s". Geophysical Research Letters. 36 (12): L12602. Bibcode:2009GeoRL..3612602R. doi:10.1029/2009GL037987.
October 21, 2023
agulhas, return, current, ocean, current, south, indian, ocean, contributes, water, exchange, between, oceans, forming, link, between, south, atlantic, current, south, indian, ocean, current, reach, velocities, knots, therefore, popular, among, participants, t. The Agulhas Return Current ARC is an ocean current in the South Indian Ocean The ARC contributes to the water exchange between oceans by forming a link between the South Atlantic Current and the South Indian Ocean Current 1 It can reach velocities of up to 4 knots 7 4 km h 4 6 mph and is therefore popular among participants in trans oceanic sailing races 2 The Agulhas Return Current ARC meanders east from the southern tip of Africa Contents 1 Oceanography 2 References 2 1 Notes 2 2 SourcesOceanography EditThe ARC originates from the Agulhas Current the western boundary current of the Indian Ocean at the Agulhas Retroflection south of Africa and flows east along the Subtropical Front roughly around 39 S north of the Antarctic Circumpolar Current 2 The Agulhas Current follows the continental shelf of the African east coast pass through the Agulhas Passage until it leaves the Agulhas Bank and reaches the Agulhas Basin south of South Africa From there it retroflects almost completely back into the south Indian Ocean as the ARC and only a smaller part known as Agulhas leakage is shed into the South Atlantic 3 The water mass loses a lot of heat at the Agulhas Retroflection up to 200 W m3 0 0076 hp cu ft while evaporation and precipitation change the composition of the upper layers The ARC therefore has another composition than the Agulhas Current proper 3 It also loses velocity from 110 75 cm s 43 30 in s and volume transport from 70 to 54 million m s Furthermore all traces of Indian Tropical Surface Water are gone 4 Having left the retroflection the ARC meanders east between 36 S and 41 S 5 These meanders were described as Rossby waves in 1970 6 and are known to shed cold eddies equatorward and enhance the primary productivity at the Subtropical Front 7 The ARC makes a large quasi permanent northward meander around the Agulhas Plateau after which it loses more velocity and volume by leakage into the South Indian subtropical gyre Over the Crozet Basin the last remnants of the ARC are gone 4 As it enters the Crozet Basin at 53 E the transport of the ARC is 35 Sv most of which is recirculated northward before reaching the Kerguelen Amsterdam Passage 8 The current east of the Crozet Basin at 66 E 70 E is called the South Indian Ocean Current and lacks the distinctive features of the ARC 4 References EditNotes Edit Lutjeharms amp Ansorge 2001 Abstract p 35 a b Boebel et al 2003 Introduction pp 35 37 a b Lutjeharms amp Ansorge 2001 Introduction pp 115 117 a b c Lutjeharms amp Ansorge 2001 Conclusions pp 135 136 Rouault Penven amp Pohl 2009 Harris 1970 Lutjeharms et al 2004 Park Gamberoni amp Charriaud 1993 Abstract Sources Edit Boebel O Rossby T Lutjeharms J Zenk W Barron C 2003 Path and variability of the Agulhas Return Current PDF Deep Sea Research Part II Topical Studies in Oceanography 50 1 35 56 doi 10 1016 S0967 0645 02 00377 6 Retrieved 15 May 2015 Harris T F W 1970 Planetary type Waves in the South West Indian Ocean Nature 227 5262 1043 1044 doi 10 1038 2271043a0 S2CID 4166656 Lutjeharms J R E Ansorge I J 2001 The Agulhas return current PDF Journal of Marine Systems 30 1 115 138 doi 10 1016 s0924 7963 01 00041 0 Retrieved 15 May 2015 Lutjeharms J Ansorge I Grundlinch M Ballegooyen R van Weeks C Machu E Boebel O 2004 Comment on New Global Drifter Data Set Available Eos Transactions American Geophysical Union 85 19 188 Bibcode 2004EOSTr 85 188K doi 10 1029 2004EO190010 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Park Y H Gamberoni L Charriaud E 1993 Frontal structure water masses and circulation in the Crozet Basin Journal of Geophysical Research 98 C7 12361 12385 Bibcode 1993JGR 9812361P doi 10 1029 93JC00938 Rouault M Penven P Pohl B 2009 Warming in the Agulhas Current system since the 1980s Geophysical Research Letters 36 12 L12602 Bibcode 2009GeoRL 3612602R doi 10 1029 2009GL037987 Retrieved from https en wikipedia org w index php title Agulhas Return Current amp oldid 1051904851, wikipedia, wiki, book, books, library,
