Influences of the Great Whirl on surface chlorophyll <i>a</i> concentration off the Somali Coast in 2017

Lingxing Dai; Bing Han; Shilin Tang; Chuqun Chen; Yan Du

doi:10.1007/s13131-021-1740-3

Volume 40 Issue 11

Nov. 2021

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Lingxing Dai, Bing Han, Shilin Tang, Chuqun Chen, Yan Du. Influences of the Great Whirl on surface chlorophyll a concentration off the Somali Coast in 2017[J]. Acta Oceanologica Sinica, 2021, 40(11): 79-86. doi: 10.1007/s13131-021-1740-3

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Lingxing Dai, Bing Han, Shilin Tang, Chuqun Chen, Yan Du. Influences of the Great Whirl on surface chlorophyll a concentration off the Somali Coast in 2017[J]. Acta Oceanologica Sinica, 2021, 40(11): 79-86. doi: 10.1007/s13131-021-1740-3

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Influences of the Great Whirl on surface chlorophyll a concentration off the Somali Coast in 2017

doi: 10.1007/s13131-021-1740-3

Lingxing Dai^{1, 2},
Bing Han^{1, 3},
Shilin Tang^{1, 3},
Chuqun Chen^{1, 2, 3},
Yan Du^{1, 2, 3
,
,}

1.
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, and China-Pakistan Joint Research Center on Earth Sciences, Chinese Academy of Sciences, Guangzhou 510301, China
2.
University of Chinese Academy of Sciences, Beijing 100049, China
3.
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China

Funds: The National Natural Science Foundation of China under contract Nos 41830538 and 42090042; the Chinese Academy of Sciences Fund under contract Nos XDA15020901, 133244KYSB20190031, ZDRW-XH-2019-2, ISEE2021PY02 and ISEE2021ZD01; Guangdong Basic and Applied Basic Research Fund under contract No. 2020A1515010498; the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) Fund under contract Nos GML2019ZD0303 and 2019BT02H594.

More Information

Corresponding author: E-mail: duyan@scsio.ac.cn
Received Date: 2020-09-03
Accepted Date: 2020-09-25

Available Online: 2021-06-24

Publish Date: 2021-11-30

Abstract

Abstract

The general features of the Great Whirl (GW) off the Somali Coast in 2017 and its influences on chlorophyll a (Chl a) concentration were studied by using satellite data and model outputs. Results show that GW, which initiated at 7°N, 53°E on June 13, had a lifetime of 153 d with an average amplitude of 16 cm and an average radius of 205 km. After the formation of GW, the concentration of Chl a in the interior of GW showed a downward trend throughout its life cycle, except in early July and mid-October. In early July, the Chl a blooms in the interior of GW were attributed to the combined effect of three processes. They are eddy horizontal transportation, the deepening of the mixed layer caused by the monsoon and eddy pumping, and the upward transportation of nutrients caused by eddy-induced Ekman pumping. In October, the Chl a blooms were probably due to the weakening of GW. During the period, water exchange occurred more frequently across the eddy, thus phytoplanktons were imported into the interior of GW.
- Great Whirl,
- chlorophyll a,
- mixed-layer,
- eddy-induced Ekman pumping,
- summer monsoon

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References(39)

References

[1]	Atlas R, Hoffman R N, Ardizzone J, et al. 2011. A Cross-Calibrated, Multiplatform ocean surface wind velocity product for meteorological and oceanographic applications. Bulletin of the American Meteorological Society, 92(2): 157–174. doi: 10.1175/2010BAMS2946.1
[2]	Beal L M, Donohue K A. 2013. The Great Whirl: Observations of its seasonal development and interannual variability. Journal of Geophysical Research: Oceans, 118(1): 1–13. doi: 10.1029/2012JC008198
[3]	Brock J C, McClain C R, Luther M E, et al. 1991. The phytoplankton bloom in the northwestern Arabian Sea during the southwest monsoon of 1979. Journal of Geophysical Research: Oceans, 96(C1): 20623–20642
[4]	Chelton D B, Schlax M G, Samelson R M. 2011. Global observations of nonlinear mesoscale eddies. Progress in Oceanography, 91(2): 167–216. doi: 10.1016/j.pocean.2011.01.002
[5]	D’Ovidio F, De Monte S, Penna A D, et al. 2013. Ecological implications of eddy retention in the open ocean: a Lagrangian approach. Journal of Physics A Mathematical and Theoretical, 46(25): 254023. doi: 10.1088/1751-8113/46/25/254023
[6]	Falkowski P G, Ziemann D, Kolber Z, et al. 1991. Role of eddy pumping in enhancing primary production in the ocean. Nature, 352(6330): 55–58. doi: 10.1038/352055a0
[7]	Fischer J, Schott F A, Stramma L. 1996. Currents and transports of the Great Whirl-Socotra Gyre system during the summer monsoon, August 1993. Journal of Geophysical Research: Oceans, 101(C2): 3573–3587. doi: 10.1029/95JC03617
[8]	Garçon V C, Oschlies A, Doney S C, et al. 2001. The role of mesoscale variability on plankton dynamics in the North Atlantic. Deep- Sea Research Part II:Topical Studies in Oceanography, 48(10): 2199–2226. doi: 10.1016/S0967-0645(00)00183-1
[9]	Gaube P, Mcgillicuddy D J Jr, Chelton D B, et al. 2014. Regional variations in the influence of mesoscale eddies on near ‐ surface chlorophyll. Journal of Geophysical Research: Oceans, 119(12): 8195–8220. doi: 10.1002/2014JC010111
[10]	Halpern D. 2002. Offshore Ekman transport and Ekman pumping off Peru during the 1997–1998 El Niño. Geophysical Research Letters, 29(5): 1075
[11]	Jensen T G. 1991. Modeling the seasonal undercurrents in the Somali Current system. Journal of Geophysical Research: Oceans, 96(C12): 22151–22167. doi: 10.1029/91JC02383
[12]	Kara B A, Rochford P A, Hurlburt H E. 2003. Mixed layer depth variability over the global ocean. Journal of Geophysical Research: Oceans, 108(C3): 3079. doi: 10.1029/2000JC000736
[13]	Kawamiya M. 2001. Mechanism of offshore nutrient supply in the western Arabian Sea. Journal of Marine Research, 59(5): 675–696. doi: 10.1357/002224001762674890
[14]	Lévy M, Shankar D, André J M, et al. 2007. Basin-wide seasonal evolution of the Indian Ocean’s phytoplankton blooms. Journal of Geophysical Research: Oceans, 112(C12): C12014. doi: 10.1029/2007JC004090
[15]	Lee C M, Jones B H, Brink K H, et al. 2000. The upper-ocean response to monsoonal forcing in the Arabian Sea: seasonal and spatial variability. Deep-Sea Research Part II: Topical Studies in Oceanography, 47(7–8): 1177–1226
[16]	Letelier R M, Karl D M, Abbott M R, et al. 2000. Role of late winter mesoscale events in the biogeochemical variability of the upper water column of the North Pacific Subtropical Gyre. Journal of Geophysical Research: Oceans, 105(C12): 28723–28739. doi: 10.1029/1999JC000306
[17]	Liao Xiaomei, Du Yan, Zhan Haigang, et al. 2014. Summertime phytoplankton blooms and surface cooling in the western south equatorial Indian Ocean. Journal of Geophysical Research: Oceans, 119(11): 7687–7704. doi: 10.1002/2014JC010195
[18]	Liao Xiaomei, Zhan Haigang, Du Yan. 2016. Potential new production in two upwelling regions of the western Arabian Sea: Estimation and comparison. Journal of Geophysical Research: Oceans, 121(7): 4487–4502. doi: 10.1002/2016JC011707
[19]	Madec G. 2008. NEMO Ocean Engine. Paris: France: Institut Pierre-Simon Laplace (IPSL), 1288–1619
[20]	Madec G, Imbard M. 1996. A global ocean mesh to overcome the North Pole singularity. Climate Dynamics, 12(6): 381–388. doi: 10.1007/BF00211684
[21]	Mahadevan A. 2014. Ocean Science: eddy effects on biogeochemistry. Nature, 506(7487): 168–169. doi: 10.1038/nature13048
[22]	McCreary J P, Kundu P K. 1988. A numerical investigation of the somali current during the southwest monsoon. Journal of Marine Research, 46(1): 25–58. doi: 10.1357/002224088785113711
[23]	McCreary J P, Murtugudde R, Vialard J, et al. 2009. Biophysical processes in the indian ocean. In: Wiggert J D, ed. Indian Ocean Biogeochemical Processes and Ecological Variability. Washington, D C: American Geophysical Union
[24]	McGillicuddy D J Jr. 2016. Mechanisms of physical-biological-biogeochemical interaction at the oceanic mesoscale. Annual Review of Marine Science, 8: 125–159. doi: 10.1146/annurev-marine-010814-015606
[25]	McGillicuddy D J Jr, Anderson L A, Doney S C, et al. 2003. Eddy-driven sources and sinks of nutrients in the upper ocean: results from a 0.1 resolution model of the North Atlantic. Global Biogeochemical Cycles, 17(2): 1035
[26]	McGillicuddy D J Jr, Robinson A R, Siegel D A, et al. 1998. Influence of mesoscale eddies on new production in the Sargasso Sea. Nature, 394(6690): 263–266. doi: 10.1038/28367
[27]	Melzer B A, Jensen T G, Rydbeck A V. 2019. Evolution of the great whirl using an Altimetry-Based eddy tracking algorithm. Geophysical Research Letters, 46(8): 4378–4385. doi: 10.1029/2018GL081781
[28]	Oschlies A, Garçon V. 1998. Eddy-induced enhancement of primary production in a model of the North Atlantic Ocean. Nature, 394(6690): 266–269. doi: 10.1038/28373
[29]	Pujol M I, Faugère Y, Taburet G, et al. 2016. DUACS DT2014: the new multi-mission altimeter data set reprocessed over 20 years. Ocean Science, 12(5): 1067–1090. doi: 10.5194/os-12-1067-2016
[30]	Renault L, Dewitte B, Marchesiello P, et al. 2012. Upwelling response to atmospheric coastal jets off central Chile: A modeling study of the October 2000 event. Journal of Geophysical Research: Oceans, 117(C2): C02030
[31]	Risien C M, Chelton D B. 2008. A global climatology of surface wind and wind stress fields from eight years of QuikSCAT scatterometer data. Journal of Physical Oceanography, 38(11): 2379–2413. doi: 10.1175/2008JPO3881.1
[32]	Schott F A, Jürgen F, Garternicht U, et al. 1997. Summer monsoon response of the Northern Somali Current, 1995. Geophysical Research Letters, 24(21): 2565–2568. doi: 10.1029/97GL00888
[33]	Schott F A, McCreary J P Jr. 2001. The monsoon circulation of the Indian Ocean. Progress in Oceanography, 51(1): 1–123. doi: 10.1016/S0079-6611(01)00083-0
[34]	Siegel D A, McGillicuddy D J Jr, Fields E A. 1999. Mesoscale eddies, satellite altimetry, and new production in the Sargasso Sea. Journal of Geophysical Research: Oceans, 104(C6): 13359–13379. doi: 10.1029/1999JC900051
[35]	Siegel D A, Peterson P, McGillicuddy D J Jr, et al. 2011. Bio-optical footprints created by mesoscale eddies in the Sargasso Sea. Geophysical Research Letters, 38(13): L13608
[36]	Schott F A, Xie Shangping, McCreary J P Jr. 2009. Indian Ocean circulation and climate variability. Reviews of Geophysics, 47(1): RG1002
[37]	Wiggert J D, Hood R R, Banse K, et al. 2005. Monsoon-driven biogeochemical processes in the Arabian Sea. Progress in Oceanography, 65(2–4): 176–213
[38]	Wirth A, Willebrand J, Schott F A. 2002. Variability of the Great Whirl from observations and models. Deep-Sea Research Part II: Topical Studies in Oceanography, 49(7–8): 1279–1295
[39]	Young D K, Kindle J C. 1994. Physical processes affecting availability of dissolved silicate for diatom production in the Arabian Sea. Journal of Geophysical Research: Oceans, 99(C11): 22619–22632. doi: 10.1029/94JC01449