Genesis and Trends in Marine Heatwaves Over the Tropical Indian Ocean and Their Interaction With the Indian Summer Monsoon

Saranya, J S; Roxy, Mathew Koll; Dasgupta, Panini; Anand, Ajay

doi:10.1029/2021jc017427

Cited by 54 publications

(39 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a previous study [24], the north BOB is noted as the region displaying a high rate of increases in MHW days and frequency during Indian summer monsoon seasons. However, the trend and interannual variability of the BOB MHWs during the climatological warmest season lack investigations, which is the motivation of the present study.…”

Section: Discussion and Summarymentioning

confidence: 84%

“…The close correlation between the local mean SST and MHW days and frequency suggest that the background monthly mean atmospheric and oceanic conditions caused by climate change are important for the formation of MHWs. The heat budget analyses conducted by, for example, Li and Wang [22] and Saranya et al [24] are required to fully unravel the physical processes of the BOB MHWs occurring at different locations and during different seasons. The linear trend caused by global warming has not fully emerged for the warm season MHWs in the BOB in recent decades, but once the background temperatures significantly changes, it would fuel more powerful and devastating MHWs.…”

Section: Discussion and Summarymentioning

confidence: 99%

“…El Niño events may associate with the diversity of local atmospheric and oceanic condition changes during different El Niño events. The negative phase of NAO is also suggested to coincide with MHW occurrences in the Indian Ocean [24]. The detailed relationship between the BOB MHWs and typical climate modes has not been systematically studied.…”

Section: Interannual Variability Of the Bob Mhwsmentioning

confidence: 99%

“…Climate modes play an important role in modulating the variability of MHWs, but the dominant modes substantially vary across regions. Generally, MHWs are closely associated with the El Niño and Southern Oscillation (ENSO), the Indian Ocean basin mode (IOB) and dipole mode (IOD) and the Pacific Decadal Oscillation (PDO) in Indo-Pacific regions [19][20][21][22][23][24][25][26]. The North Atlantic Oscillation (NAO) is also shown to be connected with the formation of Indian Ocean MHWs [13,24].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the BOB suffers powerful and deadly tropical cyclones as it supplies warm SSTs and high humidity year-around. Additional extreme and prolonged warming beyond the high SSTs can cause severe disasters in marine ecosystems, such as the 2010 Andaman sea MHW [28], and may even regulate the Indian summer monsoon [24] and cyclone activities. However, the BOB MHWs during the last decades have lacked systematic and in-depth investigations, with their evolution features in recent decades remaining unclear.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

The Trend and Interannual Variability of Marine Heatwaves over the Bay of Bengal

Gao

Liu

et al. 2022

Atmosphere

View full text Add to dashboard Cite

Marine heatwaves (MHWs) are long-lasting extreme oceanic warming events that can cause devastating effects on warm-water corals and associated ecosystems. The linear trend and interannual variability of MHWs over the Bay of Bengal (BOB) during 1982–2020 are investigated by a high-resolution daily sea surface temperature (SST) dataset. In regions where warm-water coral reefs are concentrated, annual MHW days and frequency significantly increase during 1982–2020, at rates exceeding that of the global mean. The coldest boreal winter season witnesses significant and steady increase trends in MHW days and frequency. In contrast, the trend is insignificant in the climatological warmest season (March to June) south of 15° N in the BOB, mainly due to large interannual variability. El Niño and Southern Oscillation (ENSO) dominates the interannual variability of BOB MHWs, which are highly consistent with the evolution of the mean SST. The negative phase of North Atlantic Oscillation (NAO) also modulates the occurrences of MHWs, especially over the northeastern BOB. The two climate modes synergistically explain about 50~70% of the interannual variances in the BOB’s MHWs. Correlation analysis reveals that south of 15° N in the BOB, the effect of El Niño on MHWs is evident from the boreal autumn of its developing phase to the boreal summer of its decaying phase, along with limited influence from NAO. However, in the northeast of the BOB, the effect of El Niño merely emerges from April to August of its decaying stage. In comparison, boreal winter-to-spring NAO exerts a strong control over March-to-June MHWs in the northeastern BOB. The results suggest that various climate modes may jointly or separately influence MHWs at certain seasons and locations, which is important for the seasonal prediction of MHWs. Indeed, when combining the Niño3.4 mature winter index and boreal winter-to-spring NAO index to build a regression model, it is more effective in reproducing the BOB’s MHW frequency compared to the Niño3.4 index alone.

show abstract

Section: Discussion and Summarymentioning

confidence: 84%

Section: Discussion and Summarymentioning

confidence: 99%

Section: Interannual Variability Of the Bob Mhwsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Trend and Interannual Variability of Marine Heatwaves over the Bay of Bengal

Gao

Liu

et al. 2022

Atmosphere

View full text Add to dashboard Cite

show abstract

Climatology and variability of wind speeds along the southwest coast of India derived from Climate Forecast System Reanalysis winds

Abdulla

Aboobacker

Shanas

et al. 2022

Intl Journal of Climatology

View full text Add to dashboard Cite

Wind climate along the southwest coast of India (Kerala coast) has been analysed using 41 years of Climate Forecast System Reanalysis (CFSR) winds to delineate long-term trends and variability. The study reveals significant decreasing trends in annual mean wind speeds, of the order of −2.0 to −2.5 cmÁs −1 Áyear −1 , for the period 1979-2019. Southwest monsoon has contributed the highest weakening trends (−3.0 to −4.0 cmÁs −1 Áyear −1 ) due to significant decrease in the southwesterly/westerly wind speeds. The wind climate and trends during the northeast monsoon and premonsoon seasons have been characterized largely by the prevalence of sea breeze and shamal-makran wind systems. We find that the intensity of both sea breeze and shamal-makran wind systems reduces from north to south along the Kerala coast, which is in consistent with the earlier studies. Decadal oscillations in wind speeds, driven by the decadal variability in large-scale atmosphere-ocean circulations, are evident.Recent changes in the frequency of occurrence of Indian Ocean Dipole in the Indian Ocean have determined the overturning trends since 2010, and resulted in increasing trends in the current decade along the central and northern coasts of Kerala. Furthermore, interannual variability in wind speeds has been linked to the El Niño-Southern Oscillations (ENSO) and Indian Ocean Dipole (IOD).

show abstract

Comparative changes in seasonal marine heatwaves and cold spells over the Tropical Indian Ocean during recent decades and disentangling the drivers of highly intense events

Dinesh,

Mishra,

Dubey

et al. 2023

Intl Journal of Climatology

View full text Add to dashboard Cite

The unprecedented increase in the Sea Surface Temperature (SST) in the warming climate yield stress to the system and pose severe threats to the marine ecosystem. Marine Heatwaves (MHWs) and Marine Cold Spells (MCSs) are two extreme events related to SST variability. For better management of ocean productivity, marine ecosystem, marine services, and fisheries, the understanding of seasonal discrepancies rather than annual documentation of MHWs and MCSs metrics is more utilitarian. This study documents the decadal changes in the MHWs and MCSs over the Tropical Indian Ocean (TIO) for all seasons. Additionally, highly intense events (based on intensity and duration) are identified and demonstrate the associated drivers. During the past two decades (1982–1990, 1991–2000), the MCSs were more frequent than MHWs in every season. However, in the recent two decades (2001–2010, 2011–2020), TIO become more prone to MHWs with considerably more frequent and prolonged events in JJAS months. Moreover, MCSs are disappearing from the TIO. It was noted that the choice of baseline period has an impact on the magnitude of MHWs and MCSs changes, but the spatial pattern (regions with high/low magnitude MHWs and MCSs) stays fairly constant in all baseline period sensitivity checks. The investigation of highly intense events reveals that MHWs and MCSs are produced and sustained by the same drivers when they are at their opposing edges. In general, the coherence effort from winds, net heat fluxes (shortwave radiation, longwave radiation, latent heat flux, and sensible heat flux), mixed level depth, and mean sea level pressure contribute to the genesis of seasonal MHWs or MCSs events. Additionally, in some cases, a single driver (e.g., wind) may also play a crucial role in these extreme events. The remote climate modes of variability, such as El Niño–Southern Oscillation, also contribute significantly to the MHWs and MCSs. El Niño (La Niña) events not only increase the spatial coverage of MHWs (MCSs) but also increases the intensity.

show abstract

Genesis and Trends in Marine Heatwaves Over the Tropical Indian Ocean and Their Interaction With the Indian Summer Monsoon

Cited by 54 publications

References 40 publications

The Trend and Interannual Variability of Marine Heatwaves over the Bay of Bengal

The Trend and Interannual Variability of Marine Heatwaves over the Bay of Bengal

Climatology and variability of wind speeds along the southwest coast of India derived from Climate Forecast System Reanalysis winds

Comparative changes in seasonal marine heatwaves and cold spells over the Tropical Indian Ocean during recent decades and disentangling the drivers of highly intense events

Contact Info

Product

Resources

About