Response mechanism of the surface chlorophyll concentration to ENSO cycle influenced by North Equatorial Countercurrent during autumn and winter transition period in the tropical western Pacific
-
摘要: 在厄尔尼诺−南方涛动（El Niño Southern-Oscillation, ENSO）的发生、发展中，北赤道逆流（ North Equatorial Countercurrent, NECC ）也有明显的年际变化，但北赤道逆流的变化如何影响海洋水文生态条件的变化过程尚不清楚。本文以位于热带西太平洋的北赤道逆流影响区为研究海区，分析了2006−2022年ENSO循环期间研究区不同阶段秋冬转换期水文生态气候条件的变化特征。结果表明，北赤道逆流源区及其路径上存在海表叶绿素浓度高值条带，这是由北赤道逆流从其源区携带的和新几内亚海岸潜流携带的营养物质共同影响下形成的，棉兰老冷穹上升流也会对其营养盐供给产生较大影响。厄尔尼诺事件发生时，热带西太平洋西风事件增多，北赤道逆流增强，大量表层水东移，研究区海平面降低，深水向浅层补给增加，深层冷水上抬，共同增强的北赤道逆流、新几内亚海岸流、新几内亚海岸潜流和棉兰老冷穹上升流将更多的养分从水平和垂直层面输送到海面，导致海面叶绿素浓度和原位有机碳总量显著增加。拉尼娜事件发生时，北赤道逆流影响区生态水文气候条件变化与厄尔尼诺事件发生时的变化特征几乎相反，但其变化程度弱于厄尔尼诺时期，共同减弱的北赤道逆流、新几内亚海岸潜流和棉兰老冷穹上升流使从水平和垂直层面输送到海面的养分显著减少，导致海面叶绿素浓度和原位有机碳总量显著降低。本文提出了北赤道逆流影响区水文生态气候条件演化对厄尔尼诺事件和拉尼娜事件的响应机制模型，这有利于进一步分析ENSO循环在局地生态效应和水文气候演化中的作用，对认识全球气候变化对物质循环的影响具有重要意义。
-
关键词:
- 北赤道逆流 /
- 厄尔尼诺−南方涛动（ ENSO ） /
- 海洋环境要素 /
- 热带西太平洋
Abstract: There are also obvious inter-annual variations of the North Equatorial Countercurrent (NECC) during the occurrence and development of the El Niño-Southern Oscillation (ENSO), but its changing process in hydroecological conditions and response mechanism influenced by ENSO cycle are still unclear. Taking the NECC affected area in the tropical western Pacific as the study area, this paper analyzes the characteristics of the changes of hydroecoclimatic conditions at different stages during the ENSO cycle during autumn and winter transition period from 2006 to 2022. Results reveal that there are high chlorophyll concentration bands in the NECC source area and its path, which are formed by the combined influence of nutrients carried by the NECC from its source area and the New Guinea coastal Undercurrent. The upwelling of the Mindanao Dome also has a great influence on the nutrient supply. When El Niño events occurred, the westerly wind events in the tropical western Pacific increased, the NECC strengthened, a large amount of surface water moved eastward, the sea level in the study area decreased, the deep water recharge to the shallow layer increased, and the deep cold water rose. The jointly enhanced NECC, New Guinea Coastal Current, New Guinea Coastal Undercurrent and Mindanao Dome upwelling transport more nutrients to the sea surface from both horizontal and vertical levels, resulting in significant increases in surface chlorophyll concentration and primary organic carbon production by all types of phytoplankton. When La Niña events occurred, the changes of ecohydroclimatic conditions in the NECC affected area are almost opposite to those during El Niño events, but the degree of change is weaker than that during El Nino events. The combined weakening of the NECC, the New Guinea coastal undercurrent and the Mindanao Dome upwelling significantly reduce the nutrients delivered to the sea surface from the horizontal and vertical levels. The chlorophyll concentration and primary organic carbon production by all types of phytoplankton decreased significantly. This paper proposes a model of the response mechanism of the evolution of hydroecoclimatic conditions in the NECC affected area to El Niño and La Niña events, which is conducive to further analysis of the role of ENSO cycle in local ecological effects and hydroclimatic evolution. It has important significance for understanding the impact of global climate change on the material cycle. -
图 1 研究区地理位置概况和洋流格局
NEC. 北赤道流；MC. 棉兰老流；KC. 黑潮；NECC. 北赤道逆流；SEC. 南赤道流；NGCC. 新几内亚沿岸流；MD. 棉兰老冷穹；ME. 棉兰老冷涡；HE. 哈马黑拉暖涡；MUC. 棉兰老潜流；NEUCs. 北赤道潜流；NGCUC. 新几内亚沿岸潜流；图中红色矩形框所示为北赤道逆流影响区（2°～8°N，127°～150°E）
Fig. 1 Geographical location and ocean current pattern of the study area
NEC. North Equatorial Current; MC. Mindanao Current; KC. Kuroshio Current; NECC. North Equatorial Counter Current; SEC. South Equatorial Current; NGCC. New Guinea Coastal Current; MD. Mindanao Dome; ME. Mindanao Eddy; HE. Halmahera Eddy; MUC. Mindanao Undercurrent; NEUCs. North Equatorial Undercurrents; NGCUC. New Guinea Coastal Undercurrent; the red rectangle represents the NECC affected area (2°−8°N, 127°−150°E)
图 2 2006−2022年海洋Niño指数（ONI）曲线分布
红色阴影和蓝色阴影分别代表不同的ENSO阶段
Fig. 2 The variations of the Oceanic Niño Index (ONI) during 2006−2022
Red and blue shades represent different ENSO stages, respectively
图 3 2006−2022年秋冬转换期北赤道逆流影响区海表面高度异常（SLA，a）、海表面温度异常（SSTA，b）、海表盐度异常（SSSA，c）、海表面水平流速异常（ZVA，d）、降水量（PA，e），原位有机碳总量异常（INTPA，f）和海表叶绿素a浓度异常（SChl aA，g）变化曲线和柱形图
红色阴影和蓝色阴影分别对应图2中不同ENSO阶段
Fig. 3 The variations curve and column chart of the sea level anomaly (SLA, a), sea surface temperature anomaly (SSTA, b), sea surface salinity anomaly (SSSA, c), zonal velocity anomaly (ZVA, d), precipitation anomaly (PA, e), primary organic carbon production by all types of Phytoplankton anomaly (INTPPA, f) and surface Chl a anomaly (SChl aA) during autumn and winter transition period during 2006−2022 in the NECC affected area
Red and blue shades represent different ENSO stages in Fig. 2, respectively
图 4 2006−2022年秋冬转换期北赤道逆流影响区海表面流速和海表叶绿素a浓度平面分布
箭头长度代表流速的大小
Fig. 4 Horizontal distribution of surface velocity and surface Chl a during autumn and winter transition period in 2006−2022 in the NECC affected area
The arrow length represents the size of surface velocity
图 5 2006−2022年秋冬转换期北赤道逆流影响区海表面流速异常和海表叶绿素a浓度异常平面分布
东向流速代表海表面流速正异常，西向流速代表海表面流速负异常，箭头长度代表异常值的大小
Fig. 5 Horizontal distribution of surface velocity anomaly and surface Chl a anomaly during autumn and winter transition period during 2006−2022 in the NECC affected area
The east velocity represents the positive surface velocity anomaly, and the west velocity represents the negative surface velocity anomaly, the arrow length represents the size of surface velocity
-
[1] Hu Dunxin, Wu Lixin, Cai Wenju, et al. Pacific western boundary currents and their roles in climate[J]. Nature, 2015, 522(7556): 299−308. doi: 10.1038/nature14504 [2] Wang Fan, Wang Jianing, Guan Cong, et al. Mooring observations of equatorial currents in the upper 1 000 m of the western Pacific Ocean during 2014[J]. Journal of Geophysical Research: Oceans, 2016, 121(6): 3730−3740. doi: 10.1002/2015JC011510 [3] Radenac M H, Léger F, Singh A, et al. Sea surface chlorophyll signature in the tropical Pacific during eastern and central Pacific ENSO events[J]. Journal of Geophysical Research: Oceans, 2012, 117(C4): C04007. [4] Hou Xueyan, Dong Qing, Xue Cunjin, et al. Seasonal and interannual variability of chlorophyll- a and associated physical synchronous variability in the western tropical Pacific[J]. Journal of Marine Systems, 2016, 158: 59−71. doi: 10.1016/j.jmarsys.2016.01.008 [5] Lim H G, Dunne J P, Stock C A, et al. Attribution and predictability of climate-driven variability in global ocean color[J]. Journal of Geophysical Research: Oceans, 2022, 127(10): e2022JC019121. doi: 10.1029/2022JC019121 [6] Lim H G, Dunne J P, Stock C A, et al. Oceanic and atmospheric drivers of Post-El-Niño chlorophyll rebound in the equatorial Pacific[J]. Geophysical Research Letters, 2022, 49(5): e2021GL096113. doi: 10.1029/2021GL096113 [7] Yuan Dongliang, Zhang Zhichun, Chu P C, et al. Geostrophic circulation in the tropical North Pacific Ocean based on Argo profiles[J]. Journal of Physical Oceanography, 2014, 44(2): 558−575. doi: 10.1175/JPO-D-12-0230.1 [8] Zhao Jun, Li Yuanlong, Wang Fan. Dynamical responses of the West Pacific North Equatorial Countercurrent (NECC) system to El Niño events[J]. Journal of Geophysical Research: Oceans, 2013, 118(6): 2828−2844. doi: 10.1002/jgrc.20196 [9] Tan Shuwen, Zhou Hui. The observed impacts of the two types of El Niño on the North Equatorial Countercurrent in the Pacific Ocean[J]. Geophysical Research Letters, 2018, 45(19): 10493−10500. [10] 陈永利, 官聪, 赵永平, 等. ENSO相联系的热带太平洋上层海洋异常环流[J]. 海洋与湖沼, 2020, 51(5): 967−977.Chen Yongli, Guan Cong, Zhao Yongping, et al. ENSO-related upper-layer ocean circulation anomaly in the tropical Pacific Ocean[J]. Oceanologia et Limnologia Sinica, 2020, 51(5): 967−977. [11] Messié M, Radenac M H. Seasonal variability of the surface chlorophyll in the western tropical Pacific from SeaWiFS data[J]. Deep-Sea Research Part I Oceanographic Research Papers, 2006, 53(10): 1581−1600. doi: 10.1016/j.dsr.2006.06.007 [12] Nava H, López N, Ramírez-García P, et al. Contrasting effects of the El Niño 2015−16 event on coral reefs from the central Pacific coast of Mexico[J]. Marine Ecology, 2021, 42(2): e12630. doi: 10.1111/maec.12630 [13] Timmermann A, An S I, Kug J S, et al. El Niño-Southern Oscillation complexity[J]. Nature, 2018, 559(7715): 535−545. doi: 10.1038/s41586-018-0252-6 [14] Codispoti L A, Flagg C N, Swift J H. Hydrographic conditions during the 2004 SBI process experiments[J]. Deep-Sea Research Part II: Topical Studies in Oceanography, 2009, 56(17): 1144−1163. doi: 10.1016/j.dsr2.2008.10.013 [15] Cullen J J. The deep chlorophyll maximum: comparing vertical profiles of chlorophyll- a[J]. Canadian Journal of Fisheries and Aquatic Sciences, 1982, 39(5): 791−803. doi: 10.1139/f82-108 [16] Eppley R W, Swift E, Redalje D G, et al. Subsurface chlorophyll maximum in August-September 1985 in the CLIMAX area of the North Pacific[J]. Marine Ecology Progress Series, 1988, 42: 289−301. doi: 10.3354/meps042289 [17] Kashino Y, Ishida A, Hosoda S. Observed ocean variability in the Mindanao Dome Region[J]. Journal of Physical Oceanography, 2011, 41(2): 287−302. doi: 10.1175/2010JPO4329.1 [18] Zhao Jun, Li Yuanlong, Wang Fan. Seasonal variation of the surface North Equatorial Countercurrent (NECC) in the western Pacific Ocean[J]. Chinese Journal of Oceanology and Limnology, 2016, 34(6): 1332−1346. doi: 10.1007/s00343-016-5119-9 [19] Christian J R, Murtugudde R, Ballabrera-Poy J, et al. A ribbon of dark water: phytoplankton blooms in the meanders of the Pacific North Equatorial Countercurrent[J]. Deep Sea Research Part II: Topical Studies in Oceanography, 2004, 51(1/3): 209−228. [20] Kuroda Y. Variability of currents off the northern coast of New Guinea[J]. Journal of Oceanography, 2000, 56(1): 103−116. doi: 10.1023/A:1011122810354 [21] Kaneko I, Takatsuki Y, Kamiya H, et al. Water property and current distributions along the WHP-P9 section (137°−142°) in the western North Pacific[J]. Journal of Geophysical Research: Oceans, 1998, 103(C6): 12959−12984. doi: 10.1029/97JC03761 [22] Cane M A. The evolution of El Niño, past and future[J]. Earth & Planetary Science Letters, 2005, 230(3–4): 0–240. [23] Chen Dake, Lian Tao, Fu Congbin, et al. Strong influence of westerly wind bursts on El Niño diversity[J]. Nature Geoscience, 2015, 8(5): 339−345. doi: 10.1038/ngeo2399 [24] Gao Wei, Wang Zhenyan, Huang Haijun. Variations of the Eco-Hydro-Climatic environment response to the 2015/2016 super El Niño event in the Mindanao dome upwelling system[J]. Journal of Ocean University of China, 2022, 21(1): 69−80. doi: 10.1007/s11802-022-4695-x [25] Gao Wei, Wang Zhenyan, Zhang Ronghua, et al. Variability of the Mindanao Dome upwelling system during ENSO event from 2010 to 2015[J]. Deep Sea Research Part I: Oceanographic Research Papers, 2022, 189: 103875. doi: 10.1016/j.dsr.2022.103875 [26] Gorgues T, Menkes C, Slemons L, et al. Revisiting the La Niña 1998 phytoplankton blooms in the equatorial Pacific[J]. Deep-Sea Research Part I: Oceanographic Research Papers, 2010, 57(4): 567−576. doi: 10.1016/j.dsr.2009.12.008 -
下载:
点击查看大图
计量
- 文章访问数: 94
- HTML全文浏览量: 47
- PDF下载量: 28
- 被引次数: 0
