NOAA National Environmental Satellite, Data, and Information Service, Center for Satellite Applications and Research, E/RA3, 5830 University Research Ct., College Park, MD, 20740, USA.
CIRA at Colorado State University, Fort Collins, CO, 80523, USA.
Sci Rep. 2021 Jan 28;11(1):2452. doi: 10.1038/s41598-021-81410-5.
The 2019 positive Indian Ocean Dipole (IOD) event in the boreal autumn was the most serious IOD event of the century with reports of significant sea surface temperature (SST) changes in the east and west equatorial Indian Ocean. Observations of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) between 2012 and 2020 are used to study the significant biological dipole response that occurred in the equatorial Indian Ocean following the 2019 positive IOD event. For the first time, we propose, identify, characterize, and quantify the biological IOD. The 2019 positive IOD event led to anomalous biological activity in both the east IOD zone and west IOD zone. The average chlorophyll-a (Chl-a) concentration reached over ~ 0.5 mg m in 2019 in comparison to the climatology Chl-a of ~ 0.3 mg m in the east IOD zone. In the west IOD zone, the biological activity was significantly depressed. The depressed Chl-a lasted until May 2020. The anomalous ocean biological activity in the east IOD zone was attributed to the advection of the higher-nutrient surface water due to enhanced upwelling. On the other hand, the dampened ocean biological activity in the west IOD zone was attributed to the stronger convergence of the surface waters than that in a normal year.
2019 年秋季北印度洋正位相印度洋偶极子（IOD）事件是本世纪最严重的一次 IOD 事件，报告称赤道东、西印度洋海表温度（SST）发生了显著变化。利用 2012 年至 2020 年间搭载在“苏玛尼”国家极轨伙伴卫星（SNPP）上的可视红外成像辐射计套件（VIIRS）观测数据，研究了在 2019 年正位相 IOD 事件之后发生在赤道印度洋的显著生物偶极子响应。我们首次提出、识别、描述和量化了生物 IOD。2019 年正位相 IOD 事件导致东IOD 区和西 IOD 区都出现了异常的生物活动。与东 IOD 区的气候学叶绿素-a（Chl-a）浓度约为 0.3 mg/m 相比，2019 年的平均 Chl-a 浓度达到了约 0.5 mg/m。在西 IOD 区，生物活动显著受到抑制。这种抑制性的 Chl-a 持续到 2020 年 5 月。东 IOD 区异常的海洋生物活动归因于上升流增强导致的高营养表层海水的平流。另一方面，西 IOD 区海洋生物活动的减弱归因于表层海水的辐合比正常年份更强。
