Role of multiple equatorial waves on cyclogenesis over Bay of Bengal

Landu, Kiranmayi; Goyal, Rishav; Keshav, Bibhuti Sharan

doi:10.1007/s00382-019-05112-5

Cited by 14 publications

(8 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This type of analysis is also used in many previous studies, especially studies related to cyclogenesis (e.g., Frank and Roundy, 2006). But later studies showed that the effect of the combination of different waves will be more intense than a single wave (e.g., Chen and Chou 2014; Landu et al ., 2020). Further studies are recommended and in progress to include this multiple wave combinations to understand and predict the heatwaves using these semi‐periodic oscillations.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…Most of these oscillations, also called convectively coupled equatorial waves result as the solutions to shallow water equations (Matsuno, 1966; Gill, 1980) and generate as a response of localized heating. These tropical atmospheric variations with periods less than a season (also called the tropical intraseasonal oscillations), are known to impact the weather extremes over different parts of the tropics (e.g., Matsueda and Takaya, 2015; Lubis and Jacobi, 2015; Van Der Linden et al ., 2016; Adames, 2017; Moron et al ., 2019; Subudhi and Landu, 2019; Landu et al ., 2020) including the heatwave occurrences over different parts of the tropics (e.g., Parker et al ., 2014a; Matsueda and Takaya, 2015; Ratnam et al ., 2016; Gao et al ., 2018). The continuous propagation of different phases of the large‐scale oscillations can have a significant impact on the temperature variations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of tropical sub‐seasonal variability on heatwaves over India

Zore

Landu

Gogoi

et al. 2020

Intl Journal of Climatology

Self Cite

View full text Add to dashboard Cite

One of the important consequences of changing climate is the increase in temperature extremes and heat stress over many regions of the world. Understanding the various factors that modulate these events on different time scales is of utmost importance due to their great societal relevance. For example, understanding and prediction on sub-seasonal time scales is crucial for reducing losses due to extremes and diligent management of limited resources. In this

show abstract

Section: Summary and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of tropical sub‐seasonal variability on heatwaves over India

Zore

Landu

Gogoi

et al. 2020

Intl Journal of Climatology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Also, intraseasonal SST varies inversely with the wind speed, i.e., lower wind speed coincides with warm SST anomalies and vice versa (Girishkumar et al., 2017; Sengupta & Ravichandran 2001). These ISOs impact the monsoon (Pillai & Aher, 2018; Zhang et al., 2018) and cyclone activity (Bhardwaj et al., 2019; Landu et al., 2020). Therefore, simulating the ocean processes at the ISO scale and their vertical extension in the IO is of utmost required.…”

Section: Introductionmentioning

confidence: 99%

Assessment of SCATSat‐1 Scatterometer Winds on the Upper Ocean Simulations in the North Indian Ocean

Pramanik

Sil

2021

JGR Oceans

View full text Add to dashboard Cite

are the dominant modes of intraseasonal oscillation (ISO) in the tropical ocean. These processes are described by the 30-90 days fluctuations of low-level winds and convection over the Indian Ocean (IO) and propagating from the equator to the southeast Asian region. Strong intraseasonal variability of sea surface temperature (SST) during MISO events in the tropical IO is well established and modulated by air-sea interactions, which is confirmed by both observational studies (Duvel & Vialard, 2007;Sengupta & Ravichandran, 2001) as well as modeling studies (Achuthavarier & Krishnamurthy, 2011;Fu et al., 2002). Additionally, mixed layer depth (MLD), barrier layer thickness (BLT), and salinity stratification influence the amplitude of SST in intraseasonal variability (Li et al., 2017). Strong intraseasonal SST variability is associated with shallower MLD (Sengupta Abstract The performance of a new scatterometer SCATSat-1 winds with TropFlux on simulating the upper oceanic processes is analyzed over the northern Indian Ocean (IO) using Regional Ocean Modeling System (ROMS). The nutrient, phytoplankton, zooplankton, and detritus (NPZD) ecosystem model are included for studying the postcyclonic responses on biophysical parameters during three cyclones of different intensities (Maarutha, Mora, and Ockhi) in 2017. The SCATSat-1 (TropFlux) winds showed that skill scores are higher than 0.85 (0.66), and RMSEs are less than 0.48 (1.96) m s −1 with RAMA and OMNI buoy observations. Two SCATSat-1 wind experiments, one with 1/4° (SS-E) and other regridded wind to 1° (SSR-E), are compared with the simulation by TropFlux air-sea fluxes available at 1° (TF-E). Seasonal variability of simulated oceanic parameters in SS-E and SSR-E showed marginal improvement than TF-E as compared with observations. However, SSHA variability associated with downwelling Kelvin waves along the Bay of Bengal coast and southward east India coastal current (EICC) during postmonsoon is better simulated in SCATSat-1 experiments. All experiments showed observed intraseasonal oscillations (30-90 days) with higher variability in thermocline than upper layers at RAMA locations over the equator. On western (eastern) equatorial IO, the signals are stronger during boreal winter (premonsoon) and summer (monsoon). Drop in temperature up to 2.5°C during cyclonic events is reasonably better captured in SS-E and SSR-E than TF-E due to better accuracy in SCATSat-1 winds. During cyclones, surface chlorophyll attained a peak after 5-10 days of cyclone passage in SCATSat-1 winds experiments and satellite observations. Plain Language Summary Wind plays an important role in driving the surface circulation of the ocean. Therefore, winds with reasonable accuracy are required to simulate the ocean processes at different timescales through numerical modeling. The ocean simulations are useful for studying oceanic processes and air-sea interaction. The study evaluated the performance of a scatterometer wind and a reanalysis wind. The validations with satellite and in situ observat...

show abstract

“…Recently, the role of MJO, Kelvin, ER, and MRG‐TD in cyclogenesis over Bay of Bengal (BoB) was identified by Landu et al . (2020). They concluded that cyclogenesis is favored over BoB when multiple waves are present simultaneously instead of a single wave.…”

Section: Introductionmentioning

confidence: 99%

“…Some studies have also suggested that MJO plays a dominant role in cyclogenesis modulation relative to other waves (Schreck et al, 2012;. Recently, the role of MJO, Kelvin, ER, and MRG-TD in cyclogenesis over Bay of Bengal (BoB) was identified by Landu et al (2020). They concluded that cyclogenesis is favored over BoB when multiple waves are present simultaneously instead of a single wave.…”

mentioning

confidence: 99%

Genesis of severe cyclonic storm Mora in the presence of tropical waves over the North Indian Ocean

Emmanuel

Deshpande

Ganadhi

et al. 2021

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

Tropical cyclone (TC) genesis is still a crucial mysterious problem in tropical meteorology. Over the North Indian Ocean (NIO), TC Mora genesis commenced as a depression on May 28, 2017. Kalpana‐IR satellite images indicate a disturbance that developed as a depression within Intertropical Convergence Zone (ITCZ). Tropical Rainfall Measuring Mission (TRMM) rainfall shows the organization of convection that started with clustering of clouds on May 24; thereafter, cloud patches remained intact and became a depression on May 28. During the pre‐genesis period (May 20–28), the Madden–Julian oscillation (MJO) was in phase 2 with amplitude greater than 1 and equatorial Rossby (ER) wave was also active over the Indian Basin. These waves facilitated intense convection through the supply of mid‐level moisture and low‐level vorticity required for the genesis. The presence of ER wave resulted in the formation of circulation at 850 hPa over the equatorial region. From May 22 to 23, the existence of a quasiclosed circulation (QCC) region within ER wave indicates a continuous buildup of moisture and vorticity, separating the region of moist and dry air. Later, the QCC became self‐sustained and evolved into a depression on May 28. The streamline overturning point is the inflection point (IP), and the approximate circulation center is the stagnant point (SP). The coexistence of IP and SP along with the minimum stream function and maximum column integrated total precipitable water (TPW) confirms the potential area of genesis. This criterion is applied to track the seeding of vorticity as the preferred genesis location, 5 days before genesis. These locations match well with the best track data locations provided by the India Meteorological Department after May 28. Processes within the QCC are also studied following the QCC during the formation of the depression.

show abstract

Role of multiple equatorial waves on cyclogenesis over Bay of Bengal

Cited by 14 publications

References 39 publications

Effect of tropical sub‐seasonal variability on heatwaves over India

Effect of tropical sub‐seasonal variability on heatwaves over India

Assessment of SCATSat‐1 Scatterometer Winds on the Upper Ocean Simulations in the North Indian Ocean

Genesis of severe cyclonic storm Mora in the presence of tropical waves over the North Indian Ocean

Contact Info

Product

Resources

About