Impact of Indian ocean dipole on the coastal upwelling features off the southwest coast of India

Nigam, Tanuja; Pant, Vimlesh; Prakash, Kumar Ravi

doi:10.1007/s10236-018-1152-x

Cited by 19 publications

(4 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The IOD exhibits a distinct seasonal phase-locking feature, developing in the summer, peaking in the fall, and declining rapidly in the winter (Annamalai et al, 2003(Annamalai et al, , 2005. During the positive IOD (pIOD) events, weaker southwest monsoon winds reduced the Somali Coastal Current, resulting in decreased coastal upwelling off the coasts of Oman and Somali, and higher SST in the southwestern Arabian Sea (Nigam et al, 2018;Saji & Yamagata, 2003). In contrast, the negative IOD (nIOD) events exhibited stronger southwest monsoon winds, which enhanced Somali Coastal Current, leading to increased coastal upwelling off the coasts of Oman and Somali, and shoaling of thermocline in the southwestern Arabian Sea (Thushara & Vinayachandran, 2020).…”

Section: 1029/2023gl104226mentioning

confidence: 99%

Dynamical Response of the Arabian Sea Oxygen Minimum Zone to the Extreme Indian Ocean Dipole Events in 2016 and 2019

Zhang,

Ma,

Chai

2023

Geophysical Research Letters

View full text Add to dashboard Cite

The Indian Ocean Dipole (IOD) plays a crucial role in shaping local and global environments, yet its effects on interannual variability of the Arabian Sea oxygen minimum zone (ASOMZ) remains poorly understood. Here, we used a coupled physical‐biogeochemical model to investigate the dynamical response of the ASOMZ to extreme negative (2016) and positive (2019) IOD events. Our findings revealed that the suboxic area of the ASOMZ reduced (expanded) by ∼27% (∼28%) after the negative (positive) IOD event. Compared to the 2019 pIOD event, approximately 2.5 times more oxygen‐rich water was delivered into the Arabian Sea during the 2016 nIOD event, replenishing dissolved oxygen (DO) consumed by intensified upwelling‐induced enhanced remineralization of particulate organic matter (POM), thereby increasing the DO concentration in the Gulf of Aden. Conversely, more POM from the western Arabian Sea was transported to the central Arabian Sea, leading to a subsequent decrease in DO concentration there.

show abstract

Section: 1029/2023gl104226mentioning

confidence: 99%

Dynamical Response of the Arabian Sea Oxygen Minimum Zone to the Extreme Indian Ocean Dipole Events in 2016 and 2019

Zhang,

Ma,

Chai

2023

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…To quantify the relative contribution of atmospheric heating and ocean dynamic processes to the interannual variability in the SCP's SST, the heat budget of the mixed layer was calculated. According to Nigam et al [47], the formula is as follows:…”

Section: Heat Budget Of the Mixed Layermentioning

confidence: 99%

Interannual Variabilities of the Southern Bay of Bengal Cold Pool Associated with the El Niño–Southern Oscillation

Feng

Qiu

et al. 2022

Remote Sensing

View full text Add to dashboard Cite

The southern Bay of Bengal (BOB) cold pool (SCP) plays an important role in the regional climate fluctuation of the BOB. However, the interannual variability in the SCP is still unknown. Multisource satellite remote sensing data and assimilation have been applied to explore the interannual variability in the SCP and its relationship with El Niño–Southern Oscillation (ENSO) events for the period 1982–2020. The anomalous SST of the SCP in the summer following the peak phase (i.e., winter) of the ENSO was closely related to the ENSO events. El Niño (La Niña)-induced the warm (cold) anomaly of the SCP starting from May and persisted throughout August with a peak value appearing in June during the El Niño (La Niña) decaying years. In the El Niño decaying years, the southwest monsoon current (SMC) was weakened, forced locally by the weakening southwesterly wind and remotely by the easterly wind anomaly at the equator associated with El Niño. The El Niño-related weakening SMC and the associated less cold advection led to the warm anomaly of the SCP. In addition, El Niño-related atmospheric heating also made a comparable contribution to the evolution of the SCP’s SST. In the early stage (15 May to 10 June), its contribution to the warming of the SCP was much larger than that of the SMC, whereas from mid-June to August, it reversed to have a cooling effect and partially offset the advection heating induced by the SMC on the SCP. In the La Niña decaying years, similar oceanic and atmospheric processes operated but in an opposite way.

show abstract

“…The coupled physical-biogeochemical model has been set-up over the Indian Ocean (IO) basin (30 • N-30 • S and 30 • E-120 • E) (Seelanki et al, 2021) with a 1/4 • horizontal grid resolution and 40 vertical sigma layers using a Regional Ocean Modelling System (ROMS) version 3.7 (Haidvogel et al, 2008). Many studies (Jana et al, 2015;Chakraborty et al, 2018;Nigam et al, 2018;Sandeep and Pant, 2018;Dandapat et al, 2020) used the ROMS model to understand the processes and temporal and spatial variability over the NIO (such as, AS and BoB) region. The bathymetry in the model domain is adopted from the 2-min Gridded Global Relief Data (ETOPO2) (Smith and Sandwell, 1997).…”

Section: Modelmentioning

confidence: 99%

An Evaluation of the Impact of Pandemic Driven Lockdown on the Phytoplankton Biomass Over the North Indian Ocean Using Observations and Model

Seelanki

Pant

2021

Front. Mar. Sci.

Self Cite

View full text Add to dashboard Cite

The unprecedented nationwide lockdown due to the ‘coronavirus disease 2019’ (COVID-19) affected humans and the environment in different ways. It provided an opportunity to examine the effect of reduced transportation and other anthropogenic activities on the environment. In the current study, the impact of lockdown on chlorophyll-a (Chl-a) concentration, an index of primary productivity, over the northern Indian Ocean (IO), is investigated using the observations and a physical-biogeochemical model. The statistics of model validation against observations shows a correlation coefficient of 0.85 (0.89), index of agreement as 0.90 (0.91). Root mean square error of 0.45°C (0.50°C) for sea surface temperature over the Bay of Bengal (BoB) (Arabian Sea, AS) is observed. The model results are analyzed to understand the upper-oceanic physical and biological processes during the lockdown. A comparison of the observed and model-simulated data during the lockdown period (March–June, 2020) and pre-pandemic period (March–June, 2019) shows significant differences in the physical (temperature and salinity) and biogeochemical (Chl-a concentration, nutrient concentration, and dissolved oxygen) parameters over the western AS, western BoB, and regions of Sri Lanka. During the pandemic, the reduced anthropogenic activities lead to a decrease in Chl-a concentration in the coastal regions of western AS and BoB. The enhanced aerosol/dust transport due to stronger westerly winds enhanced phytoplankton biomass in the western Arabian Sea (WAS) in May–June of the pandemic period.

show abstract

Impact of Indian ocean dipole on the coastal upwelling features off the southwest coast of India

Cited by 19 publications

References 55 publications

Dynamical Response of the Arabian Sea Oxygen Minimum Zone to the Extreme Indian Ocean Dipole Events in 2016 and 2019

Dynamical Response of the Arabian Sea Oxygen Minimum Zone to the Extreme Indian Ocean Dipole Events in 2016 and 2019

Interannual Variabilities of the Southern Bay of Bengal Cold Pool Associated with the El Niño–Southern Oscillation

An Evaluation of the Impact of Pandemic Driven Lockdown on the Phytoplankton Biomass Over the North Indian Ocean Using Observations and Model

Contact Info

Product

Resources

About