Demonstrating the asymmetry of the Indian Ocean Dipole response in regional earth system model of CORDEX-SA

Mishra, Alok Kumar; Kumar, Pankaj; Dubey, Aditya Kumar; Jha, Sanjeev; Sein, Dmitry V.; Cabos, William

doi:10.1016/j.atmosres.2022.106182

Cited by 5 publications

(5 citation statements)

References 52 publications

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“…This convergence leads to an increase in precipitation across the Indian region. Numerous studies have shown this teleconnection between ENSO and the IOD with dry/wet conditions over India [32,33]. Furthermore, in the absence of IOD occurrences, the subsidence over the Indian subcontinent generated by ENSO is substituted by a convergence induced by the IOD.…”

Section: Of 20mentioning

confidence: 93%

Impacts of Sea Surface Temperature Variability in the Indian Ocean on Drought Conditions over India during ENSO and IOD Events

Kumar,

Chu,

Anand

2024

JMSE

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The characteristics of terrestrial droughts are closely linked to simultaneous fluctuations in climatic factors, notably influenced by sea surface temperature (SST). This study explores the response of vegetation photosynthesis, indicated by solar-induced chlorophyll fluorescence (SIF), in India during the summer monsoon period (JJAS) under drought conditions. Notably, statistically significant associations between SST variations in the tropical Indian Ocean and land-based drought responses (precipitation, temperature, soil moisture, and SIF) were observed, which were attributed to atmospheric teleconnections. The positive phases of El Niño and the Indian Ocean Dipole (IOD) significantly impacted SST, triggering severe droughts in India in 2009 and 2015. The results revealed that positive SST anomalies weaken monsoon flow during the onset period, reducing moisture transmission to the Indian subcontinent. In 2009, the precipitation anomaly showed severe drought conditions (<−1.5) primarily in the northwest, central northeast, and west-central subregions, respectively, with soil moisture deficit and reduced photosynthetic activity (indicated by negative SIF anomalies) mirroring precipitation anomalies. In 2015, moderate to severe drought conditions affected regions primarily in the west-central and peninsular areas, with corresponding consistency in SIF anomalies and soil moisture deficits. These conditions led to decreased photosynthetic rates and negative SIF anomalies observed across India. The findings provide insights for predicting droughts and understanding ecosystem impacts across India amidst rapidly changing climate conditions in the Indian Ocean region.

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Section: Of 20mentioning

confidence: 93%

Impacts of Sea Surface Temperature Variability in the Indian Ocean on Drought Conditions over India during ENSO and IOD Events

Kumar,

Chu,

Anand

2024

JMSE

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“…The model components have been coupled using the Ocean–Atmosphere Sea Ice Soil coupler that exchanges the information between REMO‐HD‐MPIOM at 1 day intervals, whereas information is shared every 3 hr between REMO and MPIOM. More details about the model integration and detailed dynamics can be obtained from the literature (Dubey & Kumar, 2023; Kumar et al ., 2022; Mishra et al ., 2021b; Mishra et al ., 2022; Saharwardi et al ., 2022; Sein et al ., 2015; Sein et al ., 2020; Sein et al ., 2022).…”

Section: Methodsmentioning

confidence: 99%

Analyzing future marine cold spells in the tropical Indian Ocean: Insights from a regional Earth system model

Dinesh,

Kumar,

Mishra

et al. 2024

Quart J Royal Meteoro Soc

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In this study, a future projection of marine cold spells (MCSs) over the tropical Indian Ocean is made using a fully coupled regional Earth system model, namely ROM, under two representative concentration pathways (RCPs): RCP4.5 and RCP8.5. In both RCPs, the future MCS properties have been estimated across three distinct time intervals: the near future (NF; 2010–2039), the middle future (MF; 2040–2069), and the far future (FF; 2070–2099). The future MCS computations were examined with respect to fixed historical baseline periods and varying baseline periods. MCSs were frequent, intense, and prolonged during the historical period. ROM effectively simulated these historical MCS metrics and their trends and outperformed the forcing general circulation model as well as the multimodel ensemble mean of Coupled Model Intercomparison Project phase 5 models. In the future, MCSs will cease to occur in ∼13% (4%), ∼56% (66%) and ∼69% (93%) of the area of the tropical Indian Ocean in the NF, MF, and FF respectively under the RCP4.5 (RCP8.5) scenario using a fixed historical baseline period. This departure of MCSs led to the disappearance of events, first identified over the Arabian Sea in both RCPs. The decrease in net heat flux and increase in wind speed contribute to the genesis and severity of MCS events. Further, during the El Niño regime, the MCS events dramatically decrease due to the basin‐wide warming, but during the La Niña phase, the MCS intensity and spatial range increase. This study further investigates the sensitivity of MCSs with the choice of baseline period. Adopting varying baseline periods over time does not result in the disappearance of MCSs but does produce declining trends in MCS activity, highlighting the need for careful consideration in choosing a baseline period.

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“…However, it is computationally expensive, and alternatively, high-resolution RESM can be used at a less computational cost. Various RESM having varying complexities have been developed and employed to explore the understanding of atmospheric and oceanic variability over different regions of the globe and suggest improvements (Sein et al, 2015;Wang et al, 2015;Dubey et al, 2021;Mishra et al, 2021aMishra et al, , 2021bSaharwardi et al, 2021;Kumar et al, 2022;Mishra et al, 2022aMishra et al, , 2022bMishra et al, , 2022c. Kumar et al (2022) demonstrated that dynamical and thermodynamical processes including the upper tropospheric circulation associated with the Indian summer monsoon employing the same model used in this study.…”

Section: Introductionmentioning

confidence: 99%

“…However, it is computationally expensive, and alternatively, high‐resolution RESM can be used at a less computational cost. Various RESM having varying complexities have been developed and employed to explore the understanding of atmospheric and oceanic variability over different regions of the globe and suggest improvements (Sein et al ., 2015; Wang et al ., 2015; Dubey et al ., 2021; Mishra et al ., 2021a, 2021b; Saharwardi et al ., 2021; Kumar et al ., 2022; Mishra et al ., 2022a, 2022b, 2022c). Kumar et al .…”

Section: Introductionmentioning

confidence: 99%

Regional earth system model for CORDEX‐South Asia: A comparative assessment of RESM and ESM over the tropical Indian Ocean

Kumar

Mallick

Mishra

et al. 2022

Intl Journal of Climatology

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Understanding climate variability requires good quality high resolution spatially and temporally varying ocean fields due to its decisive role in regulating the region's climate, including the Indian summer monsoon. In this regard, we employed a new high-resolution regional earth system model (RESM), namely ROM over CORDEX South Asia. We demonstrated the performance of the RESM and its added value over the global earth system model, namely MPI-ESM, in simulating the hydrographic characteristics and associated mechanism over the tropical Indian Ocean (TIO). ROM shows better skill than MPI-ESM in simulating the near-surface and subsurface characteristics of the ocean. However, larger added values are noticed for subsurface (>350 m) thermal structure. MPI-ESM's cold sea surface temperature (SST) bias is reduced in ROM which is associated with weaker winds, anomalous cyclonic wind stress curl, enhanced stratifications, and a shallower mixed layer, resulting in greater upper-ocean heating. The reduced SST bias is also consistent with improved ocean meridional heat transport (OMHT) in ROM. For example, reduced southward export of OMHT over the Arabian Sea increases the surface warming by 4%, reducing the RMSE by 0.2-0.6 C and becoming closer to observation. The anomalous cyclonic wind stress curl, in turn, caused mixed layer stratifications in the western Indian Ocean. The advective heat transfer from the south-eastern Indian Ocean to the western Indian Ocean reduced oceanic cooling by vertical processes, overcame the cooling by the net loss of surface heat fluxes, and favoured the TIO's surface warming.

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Demonstrating the asymmetry of the Indian Ocean Dipole response in regional earth system model of CORDEX-SA

Cited by 5 publications

References 52 publications

Impacts of Sea Surface Temperature Variability in the Indian Ocean on Drought Conditions over India during ENSO and IOD Events

Impacts of Sea Surface Temperature Variability in the Indian Ocean on Drought Conditions over India during ENSO and IOD Events

Analyzing future marine cold spells in the tropical Indian Ocean: Insights from a regional Earth system model

Regional earth system model for CORDEX‐South Asia: A comparative assessment of RESM and ESM over the tropical Indian Ocean

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