Decadal variation of ocean heat content and tropical cyclone activity over the Bay of Bengal

Nath, Sankar; Kotal, S. D.; Kundu, Prabir Kumar

doi:10.1007/s12040-015-0651-0

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…Geopotential height denotes the actual height of the pressure surface above mean sea level and basically indicates the position of trough and ridge in the middle troposphere (500 hPa). Negative geopotential height anomalies (low heights) indicate the trough or cyclones at mid‐tropospheric level (Nath et al, ). Composite plots of 500 hPa geopotential heights anomalies clearly indicate the distinct large scale patterns with positive anomalies during El Niño and negative anomalies during La Niña years consistent with the below normal and above normal TCs frequency (Figure a,b).…”

Section: Resultsmentioning

confidence: 99%

Tropical cyclone activity over Bay of Bengal in relation to El Niño‐Southern Oscillation

Bhardwaj

Pattanaik

Singh

2019

Intl Journal of Climatology

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The present paper investigates the impact of El Niño‐Southern Oscillation (ENSO) on the Bay of Bengal tropical cyclone (TC) activity and associated alterations in environmental conditions during post‐monsoon (October–December) season for a period of 44 years (1972–2015). The analysis reveals that the post‐monsoon season TCs frequency, accumulated cyclone energy (ACE) and power dissipation index (PDI) values are negatively correlated with the Niño 3.4 sea surface temperature (SST) anomalies (significant at the 95% confidence level). La Niña years are characterized by more frequent and intense cyclonic events compared with El Niño years. The mean ACE and PDI values are approximately two times higher in La Niña than El Niño years. The mean number of TC days per year is also higher in La Niña (7.64 days) than El Niño (3.68 days) years (significant at 95% confidence level). In addition, a significant shift in genesis locations, tracks and landfalling locations of TCs has been observed under different ENSO phases. The mean genesis location of TCs have shifted eastward with tendency of more recurving tracks in La Niña than El Niño years. The presence of strong convective activity, reduced vertical wind shear, high SST (≥28°C), enhanced mid‐tropospheric relative humidity and low‐level cyclonic circulation aids the TCs formation and strengthening during La Niña and vice‐versa in El Niño conditions.

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Section: Resultsmentioning

confidence: 99%

Tropical cyclone activity over Bay of Bengal in relation to El Niño‐Southern Oscillation

Bhardwaj

Pattanaik

Singh

2019

Intl Journal of Climatology

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“…They found that the translational speed (TS) of cyclonic disturbances over the BoB ranged from 6.4 to 9.6 km h −1 over the first four decades , and over the recent decade (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), this has increased to 17.6 km h −1 . Nath et al (2016) have also studied decadal variations of ocean heat content and TC activity over the BoB during the 1955-2013 periods. According to Rajeevan et al (2013), epochal variation in the storm's atmospheric VWS anomalies and oceanic heat content contributed to more violent TCs occurring during the most recent epoch (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011) than during the earlier epoch (1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992).…”

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confidence: 99%

Interdecadal variability of the pre-monsoon cyclone characteristics over the Bay of Bengal

Jena,

Pattnaik

2024

Environ. Res.: Climate

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The low-pressure systems intensified to cyclones prior to the onset of the Indian summer monsoon season over the North Indian Ocean (NIO) are referred to as pre-monsoon season (PMS) cyclones. Climate change is amplifying the pre-monsoon cyclone landscape, fostering more frequent and intense storms with altered tracks, resulting in heightened risks for coastal communities and economies. This study investigates the interdecadal variations in tropical cyclone (TC) and key large-scale atmospheric parameters that influence the characteristics of cyclones, including track, frequency over the Bay of Bengal (BoB) during the pre-monsoon season from 60 years of data. The large-scale atmospheric parameters are analysed by calculating climatological anomalies. It is noted that the frequency of cyclones making landfall over the eastern Indian coastal landmass has increased in the recent decade compared to the past five decades. Compared to the past fifty years, the percentage frequency has increased in the recent ten years by 50%. At the low level, stronger easterlies are dominant and upper-level jet streams shift to lower latitudes, indicating that the path of cyclones has shifted from the north (N)-northeast (NE) to the northwest (NW), i.e., towards the east Indian coastal landmass, over the recent decade. In contrast to the previous five decades, an unusual low-pressure region has emerged over the NW India and Pakistan regions, creating a favourable path for cyclones moving towards the Indian region in recent decade. Cyclones have been more intense in the recent decade than they were in the previous five decades, according to the rise in low- and mid-level specific humidity (SPH) and temperature over the BoB.

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“…studies have indicated that during the past decades, the SST has been increasing in the World Ocean and individual ocean basins (Ting et al, 2009;Large and Yeager, 2012;Reid and Beaugrand, 2012;Krokos et al, 2019;Noori et al, 2019;Hereher, 2020;Pisano et al, 2020;Garcia-Soto et al, 2021;Al Senafi, 2022) and that the same has been happening for the OHC (Levitus et al, 2000;Willis et al, 2004;Nagamani et al, 2016;Nath et al, 2016;Cheng et al, 2017;Storto et al, 2019). Belkin (2009) performed a study on large marine ecosystems and suggested a rapid warming rate for the period 1982-2006, which was stronger in small marginal seas.…”

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confidence: 99%

Contribution of surface and lateral forcing to the Arabian Gulf warming trend

Vasou,

Krokos,

Langodan

et al. 2024

Front. Mar. Sci.

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The contribution of surface and lateral forcing to the observed Arabian Gulf warming trend is studied based on the results of a high-resolution (1/100°, 60 vertical layers) MIT general circulation model (MITgcm) covering the period 1993–2021. The model validation against available observations reveals that the simulation satisfactorily reproduces the main features of the Arabian Gulf’s dynamics and their variability. We show that the heat content of the Arabian Gulf generally follows the reported variability of sea surface temperature, with significant increasing trends of 0.1 × 107 J m−3 and 0.2°C per decade. The interannual variability of the heat content is dominated by the surface heat fluxes, while the long-term warming of the basin is primarily driven by lateral fluxes. The analyses of the heat exchanges through the Strait of Hormuz indicate a pronounced upward trend in the transported heat toward the Arabian Gulf, which is associated with an increase in both the volume and temperature of the exchanged waters. Considering the inflow and outflow in the Strait separately, the temperature increase is more prominent in the inflowing waters; however, the dominant factor driving the rising trend in heat content exchanges is the increase in the volume of waters being exchanged. This implies that the observed warming of the Arabian Gulf during the investigated period is directly related to the acceleration of its overturning circulation.

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Decadal variation of ocean heat content and tropical cyclone activity over the Bay of Bengal

Cited by 7 publications

References 24 publications

Tropical cyclone activity over Bay of Bengal in relation to El Niño‐Southern Oscillation

Tropical cyclone activity over Bay of Bengal in relation to El Niño‐Southern Oscillation

Interdecadal variability of the pre-monsoon cyclone characteristics over the Bay of Bengal

Contribution of surface and lateral forcing to the Arabian Gulf warming trend

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