Comparison of mixed layer depth and barrier layer thickness for the Indian Ocean using two different climatologies

Vissa, Naresh Krishna; Satyanarayana, A. N. V.; Kumar, B. Prasad

doi:10.1002/joc.3635

Cited by 25 publications

(14 citation statements)

References 29 publications

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“…During the same period Yu and McPhaden () also reported the absence of barrier layer from RAMA buoy (15°N/ 90°E) observations. Observed features are consistent with the pre‐monsoon barrier layer climatological fields of BoB (Thadathil et al, ; Vissa et al, ). The absence of barrier layer supports strong turbulent mixing Wang et al () and further leads to sea surface cooling.…”

Section: Resultssupporting

confidence: 84%

“…The monthly climatology during April to May was taken from high spatial resolution (0.25° × 0.25°) COA developed for the Indian Ocean which utilizes ARGO data (e.g. Prasad Kumar et al, ; Vissa et al, ). ARGO gridded data at 10 days interval with 1° spatial resolution generated from individual ARGO profiles using objective analysis method (Udaya Bhaskar et al ) during 2002–2009 for the month of April is utilized in this study.…”

Section: Methodsmentioning

confidence: 99%

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Response of oceanic cyclogenesis metrics forNARGIScyclone: a case study

Vissa

Satyanarayana

Kumar

2013

Atmospheric Science Letters

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In this study, variability of two oceanic cyclogenesis metrics, tropical cyclone heat potential (TCHP) and effective oceanic layer for cyclogenesis (EOLC) in the Bay of Bengal (BoB) during NARGIS cyclone is investigated. EOLC represents the geopotential thickness of near surface stratified layer forms because of the spread of low salinity waters due to fresh water influx from rivers and precipitation. Climatological fields of TCHP and EOLC reveal that NARGIS translated towards the region of higher EOLC as seen in the observations. A maximum daily sea surface cooling of 2• C is observed along the right and rear side of NARGIS track.

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Section: Resultssupporting

confidence: 84%

Section: Methodsmentioning

confidence: 99%

Response of oceanic cyclogenesis metrics forNARGIScyclone: a case study

Vissa

Satyanarayana

Kumar

2013

Atmospheric Science Letters

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“…On 15-16 December, the BLT thinned to 45 m because of the ML deepening associated with the second peak of the surface wind speed exceeding 8 m/s. On 16-17 December, however, the MLD shallowed again, resulting in the BL thickening up to 85 m. This value is very large compared with those found in previous statistical studies (Drushka et al 2014;Sato et al 2004Sato et al , 2006Vissa et al 2013a).…”

Section: Resultsmentioning

confidence: 45%

Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign

Moteki

Katsumata

Yoneyama

et al. 2018

Prog Earth Planet Sci

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The drastic thickening of the barrier layer in the marginal sea off the western coast of Sumatra during the passage of the Madden-Julian oscillation (MJO) observed during December 2015 is investigated. Before the MJO arrival, the halocline above a depth of 20 m was very strong, and the barrier layer thickness was 5-10 m based on R/V Mirai observations. During the MJO forcing of 13-16 December, the isothermal layer drastically deepened from 20 to 100 m. Meanwhile, the mixed layer deepening lagged behind the isothermal layer deepening by 1 day, and the barrier layer underwent dramatic thickening to 60 m within 24 h. An evaluation of the vertical salinity gradient tendency showed that the dramatic thickening of the barrier layer was due to the vertical oceanic mixing by the atmospheric MJO forcing and the vertical stretching by the oceanic downwelling coastal Kelvin wave intruding from the open ocean. In addition, an evaluation of the vertical temperature gradient tendency showed that the temperature inversion in the barrier layer formed by losing heat to the atmosphere due to the MJO forcing and downward advection of the temperature gradient due to the downwelling Kelvin wave resulting in the dramatic isothermal layer deepening. One of the important factors in the drastic barrier layer thickening was the atmospheric external forcing and the oceanic internal wave being in phase. The downwelling oceanic Kelvin wave continuously lowered the thermocline from the middle of November to the end of December, and the salinity stratification in the vicinity of the thermocline was continuously mitigated by the vertical stretching. Under such conditions, the MJO forcing caused vertical mixing of the freshwater with strong salinity stratification and temperature stratification near the surface. The combination of the two distinct processes caused the drastic thickening of the barrier layer, and the barrier layer thickness reached a maximum of 85 m 5 days after the MJO arrival.

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“…Contrastingly, the BLT is smaller during the pre‐monsoon (∼12–17 m) as compared to the post‐monsoon season (∼22–33 m), owing to the large cooling (in terms of negative TCHPA) in the pre‐monsoon season (refer to Figure c–f). These results are consistent with earlier studies (Sengupta et al ., ; Vissa et al ., ).…”

Section: Resultsmentioning

confidence: 97%

The response of ocean parameters to tropical cyclones in the Bay of Bengal

Busireddy

Ankur

Osuri

et al. 2019

Quart J Royal Meteoro Soc

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The Bay of Bengal (BoB) exhibits notable seasonal variations in tropical cyclone heat potential (TCHP), barrier layer thickness (BLT) and sea‐surface temperature (SST). These parameters also undergo profound changes in the presence of tropical cyclones (TCs). The composite structures of these ocean parameters as a function of the season of TC formation, intensity, and translation speed are unknown and are developed in the present study. Composite structures are examined based on 1,222 instantaneous samples from 83 TCs during 2003–2016 using INCOIS‐GODAS analyses. A BLT of 10–30 m and TCHP of 40–80 kJ/cm2 favours TC intensification in the central BoB. The multivariate regression of BLT and TCHP appears to be better for TC intensity up to 64 knots and is highly underestimated for the stronger TCs (>64 knots). The TC right‐rear sector experiences significant changes in TCHP anomaly (TCHPA) as the intensity increases. The TCHPA ranges ∼10–15, ∼20–25 and ∼25–30 kJ/cm2 when a TC is at Cyclone Storm (CS), Severe Cyclonic Storm (SCS) and Very SCS (VSCS) stages respectively. The maximum TCHPA is generally aligned along the TC track during the post‐monsoon season. Slow‐moving TCs produce maximum TCHPA cooling of ∼20 kJ/cm2 within 250 km storm radius in the rear sector, while it is less and away from the storm centre for normal and fast‐movers. The seasonal changes showed opposite relations between BLT and TCHP from pre‐ to post‐monsoon seasons during the TC intensification. TC‐induced SST cooling is maximum (∼0.5–1.2 °C) in the inner core for the strong (VSCS and above) and slow‐moving TCs. The cooling decreases with an increase in the translation speed and is more pronounced in the pre‐monsoon season. This study provides a baseline to verify and understand the limitations of the models, and also develop a climatological perspective of BoB TCs.

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Comparison of mixed layer depth and barrier layer thickness for the Indian Ocean using two different climatologies

Cited by 25 publications

References 29 publications

Response of oceanic cyclogenesis metrics forNARGIScyclone: a case study

Response of oceanic cyclogenesis metrics forNARGIScyclone: a case study

Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign

The response of ocean parameters to tropical cyclones in the Bay of Bengal

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