What Caused the Extreme Indian Ocean Dipole Event in 2019?

2020 ◽  
Vol 47 (11) ◽  
Author(s):  
Bo Lu ◽  
Hong‐Li Ren
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Indian Ocean Dipole Event

scholarly journals A biological Indian Ocean Dipole event in 2019

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wei Shi ◽  
Menghua Wang
Keyword(s):  
Biological Activity ◽  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Infrared Imaging ◽  
Equatorial Indian Ocean ◽  
The West ◽  
Indian Ocean Dipole Event ◽  
Chl A ◽  
Positive Indian Ocean Dipole ◽  
Dipole Response

AbstractThe 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−3 in 2019 in comparison to the climatology Chl-a of ~ 0.3 mg m−3 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.

Inter-basin and Multi-time Scale Interactions in generating the 2019 Extreme Indian Ocean Dipole

2021 ◽  
pp. 1-39
Author(s):  
Lei Zhang ◽  
Weiqing Han ◽  
Zeng-Zhen Hu
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Intraseasonal Oscillation ◽  
Tropical Indian Ocean ◽  
Forecast Model ◽  
Tropical Pacific ◽  
Boreal Summer ◽  
Indian Ocean Dipole Event ◽  
Easterly Wind ◽  
Western Tropical Pacific

AbstractAn unprecedented extreme positive Indian Ocean Dipole event (pIOD) occurred in 2019, which has caused widespread disastrous impacts on countries bordering the Indian Ocean, including the East African floods and vast bushfires in Australia. Here we investigate the causes for the 2019 pIOD by analyzing multiple observational datasets and performing numerical model experiments. We find that the 2019 pIOD is triggered in May by easterly wind bursts over the tropical Indian Ocean associated with the dry phase of the boreal summer intraseasonal oscillation, and sustained by the local atmosphere-ocean interaction thereafter. During September-November, warm sea surface temperature anomalies (SSTA) in the central-western tropical Pacific further enhance the Indian Ocean’s easterly winds, bringing the pIOD to an extreme magnitude. The central-western tropical Pacific warm SSTA is strengthened by two consecutive Madden Julian Oscillation (MJO) events that originate from the tropical Indian Ocean. Our results highlight the important roles of cross-basin and cross-timescale interactions in generating extreme IOD events. The lack of accurate representation of these interactions may be the root for a short lead time in predicting this extreme pIOD with a state-of-the-art climate forecast model.

Role of a Cyclonic Eddy in the 7000-Year-Old Mentawai Coral Reef Death During the 1997 Indian Ocean Dipole Event

2010 ◽  
Vol 7 (2) ◽  
pp. 296-300 ◽  
Author(s):  
P R C Rahul ◽  
P S Salvekar ◽  
B K Sahu ◽  
Shailesh Nayak ◽  
T Srinivas Kumar
Keyword(s):  
Coral Reef ◽  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Cyclonic Eddy ◽  
Indian Ocean Dipole Event

A Unique Feature of the 2019 Extreme Positive Indian Ocean Dipole Event

2020 ◽  
Vol 47 (18) ◽  
Author(s):  
Guojian Wang ◽  
Wenju Cai ◽  
Kai Yang ◽  
Agus Santoso ◽  
Toshio Yamagata
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Unique Feature ◽  
Indian Ocean Dipole Event ◽  
Positive Indian Ocean Dipole

scholarly journals Ecological Vulnerability of Coral Reef Ecosystem in Wakatobi National Park During Indian Ocean Dipole Event

2020 ◽  
Vol 27 (1) ◽  
pp. 57
Author(s):  
Hawis H. Madduppa ◽  
Alan F. Koropitan ◽  
Ario Damar ◽  
Beginer Subhan ◽  
Muhammad Taufik ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Coral Reefs ◽  
Adaptive Capacity ◽  
Indian Ocean Dipole ◽  
Coral Cover ◽  
Indian Ocean Dipole Event ◽  
Ecological Vulnerability ◽  
Climate Exposure ◽  
Hard Coral Cover ◽  
Site Adaptability

This research examines coral reefs vulnerability which threatening its existences and functions by climate change. The ecological vulnerability in Wakatobi (Wangi-wangi, Kaledupa, Tomia, and Binongko) was assessed during Indian Ocean Dipole (IOD) event in 2016. Climate exposure was determined using sea surface temperature, chlorophyll-a concentration, and wind speed magnitude; sensitivity was determined using coral susceptibility, fish susceptibility, and macroalgae primary productivity rate; then adaptive capacity was developed by hard coral cover, coral size distribution, coral richness, fish biomass, herbivore diversity, and herbivore grazing relative to algal production. The values of Exposure, Sensitivity, and Adaptive capacity in Wakatobi were 0.93±0.02, 0.42±0.18, and 0.44±0.10, respectively. Site specific vulnerability scores ranged from 0.52 to 1.60 (mean 0.92±0.26). Binongko was the least vulnerable than other islands. Tomia was observed as the least adaptive capacity and Wangi-wangi was the most bleaching incidents. These results could help coral reefs monitoring priority during the event and then when the event is gone by focusing on the marked islands and sites. Sites that were observed as more vulnerable is urgently need a management strategy to overcome the vulnerability status in the future, such as increasing site adaptability.

scholarly journals Phytoplankton blooms induced/sustained by cyclonic eddies during the Indian Ocean Dipole event of 1997 along the southern coasts of Java and Sumatra

2008 ◽  
Vol 5 (5) ◽  
pp. 3905-3918 ◽  
Author(s):  
P. Rahul Chand Reddy ◽  
P. S. Salvekar
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
State Of The Art ◽  
Sea Surface ◽  
Phytoplankton Blooms ◽  
Indian Ocean Dipole Event ◽  
Indonesian Archipelago ◽  
The Indian Ocean ◽  
The Tropics ◽  
Sst Anomalies

Abstract. The Indonesian archipelago is the gateway in the tropics connecting two oceans (Pacific and the Indian Ocean) and two continents (Asia and Australia). During the Indian Ocean Dipole 1997, record anomalous and unanticipated upwelling had occurred along the southern coasts of Java and Sumatra causing massive phytoplankton blooms. But the method/mode/process for such anomalous upwelling was not known. Using monthly SeaWifs chlorophyll-a anomalies, TOPEX Sea Surface Height (SSH) anomalies, Sea Surface Temperatures (SST) and currents from a state-of-the-art OGCM, we report the presence of a series of cyclonic eddies along southern coasts of Sumatra and Java during November, December 1997 and January 1998. Upwelling caused by these cyclonic eddies, as also supported by the SSH and SST anomalies, has been responsible for the phytoplankton blooms to persist and dissipate during the 3 months (November, December 1997 and January 1998).

Sign in / Sign up

Export Citation Format

Share Document