Potential vorticity diagnosis of rapid intensification of very severe cyclone GIRI (2010) over the Bay of Bengal

2011 ◽  
Vol 60 (2) ◽  
pp. 461-484 ◽  
Author(s):  
S. D. Kotal ◽  
Ajit Tyagi ◽  
S. K. Roy Bhowmik
Keyword(s):  
Potential Vorticity ◽  
Bay Of Bengal ◽  
Rapid Intensification

scholarly journals Potential Vorticity Mixing and Rapid Intensification in the Numerically Simulated Supertyphoon Haiyan (2013)

2020 ◽  
Vol 77 (6) ◽  
pp. 2067-2090
Author(s):  
Satoki Tsujino ◽  
Hung-Chi Kuo
Keyword(s):  
Potential Vorticity ◽  
Inner Core ◽  
Model Simulation ◽  
Pressure Change ◽  
Central Pressure ◽  
Rapid Intensification ◽  
Budget Analysis ◽  
Tangential Wind ◽  
Balanced Dynamics ◽  
Omega Equation

Abstract The inner-core dynamics of Supertyphoon Haiyan (2013) undergoing rapid intensification (RI) are studied with a 2-km-resolution cloud-resolving model simulation. The potential vorticity (PV) field in the simulated storm reveals an elliptical and polygonal-shaped eyewall at the low and middle levels during RI onset. The PV budget analysis confirms the importance of PV mixing at this stage, that is, the asymmetric transport of diabatically generated PV to the storm center from the eyewall and the ejection of PV filaments outside the eyewall. We employ a piecewise PV inversion (PPVI) and an omega equation to interpret the model results in balanced dynamics. The omega equation diagnosis suggests eye dynamical warming is associated with the PV mixing. The PPVI indicates that PV mixing accounts for about 50% of the central pressure fall during RI onset. The decrease of central pressure enhances the boundary layer (BL) inflow. The BL inflow leads to contraction of the radius of the maximum tangential wind (RMW) and the formation of a symmetric convective PV tower inside the RMW. The eye in the later stage of the RI is warmed by the subsidence associated with the convective PV towers. The results suggest that the pressure change associated with PV mixing, the increase of the symmetric BL radial inflow, and the development of a symmetric convective PV tower are the essential collaborating dynamics for RI. An experiment with 500-m resolution shows that the convergence of BL inflow can lead to an updraft magnitude of 20 m s−1 and to a convective PV tower with a peak value of 200 PVU (1 PVU = 10−6 K kg−1 m2 s−1).

scholarly journals On the processes influencing rapid intensity changes of tropical cyclones over the Bay of Bengal

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Saiprasanth Bhalachandran ◽  
R. Nadimpalli ◽  
K. K. Osuri ◽  
F. D. Marks ◽  
S. Gopalakrishnan ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Tropical Cyclones ◽  
Bay Of Bengal ◽  
Rapid Intensification ◽  
Eddy Flux ◽  
Relative Proximity ◽  
Intensity Changes ◽  
Primary Finding ◽  
Asymmetrically Distributed ◽  
Left Quadrant

AbstractWe present a numerical investigation of the processes that influenced the contrasting rapid intensity changes in Tropical Cyclones (TC) Phailin and Lehar (2013) over the Bay of Bengal. Our emphasis is on the significant differences in the environments experienced by the TCs within a few weeks and the consequent differences in their organization of vortex-scale convection that resulted in their different rapid intensity changes. The storm-relative proximity, intensity, and depth of the subtropical ridge resulted in the establishment of a low-sheared environment for Phailin and a high-sheared environment for Lehar. Our primary finding here is that in Lehar’s sheared vortex, the juxtaposition in the azimuthal phasing of the asymmetrically distributed downward eddy flux of moist-entropy through the top of the boundary layer, and the radial eddy flux of moist-entropy within the boundary layer in the upshear left-quadrant of Lehar (40–80 km radius) establishes a pathway for the low moist-entropy air to intrude into the vortex from the environment. Conversely, when the azimuthal variations in boundary layer moist-entropy, inflow, and convection are weak in Phailin’s low-sheared environment, the inflow magnitude and radial location of boundary layer convergence relative to the radius of maximum wind dictated the rapid intensification.

Predicting the rapid intensification and dynamics of pre-monsoon extremely severe cyclonic storm ‘Fani’ (2019) over the Bay of Bengal in a 12-km global model

2021 ◽  
Vol 247 ◽  
pp. 105222
Author(s):  
Vivek Singh ◽  
Rakesh Teja Konduru ◽  
Atul Kumar Srivastava ◽  
I.M. Momin ◽  
Sushant Kumar ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Global Model ◽  
Rapid Intensification ◽  
Cyclonic Storm ◽  
Severe Cyclonic Storm

Double warm-core structure and potential vorticity diagnosis during the rapid intensification of Supertyphoon Lekima (2019)

2021 ◽  
Author(s):  
Donglei Shi ◽  
Guanghua Chen
Keyword(s):  
Potential Vorticity ◽  
Diabatic Heating ◽  
Inner Core ◽  
Deep Layer ◽  
Rapid Intensification ◽  
Latent Heat Release ◽  
Wind Fields ◽  
Warm Core ◽  
Upper Level ◽  
Pv Generation

AbstractThe rapid intensification (RI) of supertyphoon Lekima (2019) is investigated from the perspective of balanced potential vorticity (PV) dynamics using a high-resolution numerical simulation. The PV budget shows that the inner-core PV anomalies (PVAs) formed during the RI mainly comprise an eyewall PV tower generated by diabatic heating, a high-PV bridge extending into the eye resulting from the PV mixing, and an upper-tropospheric high-PV core induced by the PV intrusion from stratosphere. The inversion of the total PVA at the end of the RI captures about 90% of changes in pressure and wind fields, indicating that the storm is quasi-balanced. The piecewise PV inversion further demonstrates that the eyewall and mixed PVAs induce the upper-level and midlevel warm cores in the eye region, respectively. The two warm cores cause nearly all the balanced central pressure decrease and thus dominate the RI, with the contribution of the upper warm core being twice that of the midlevel one. In contrast, the upper-tropospheric PV core induces significant warming near the tropopause and deep-layer cooling beneath, reinforcing the upper-level warm core but causing little surface pressure drop.By comparing the diabatic PV generation due to the convective burst (CB) and non-CB precipitation, we found that the non-CB precipitation accounts for a larger portion for the eyewall PVA and thus the associated upper-level warming, distinct from previous studies that primarily attributed the upper-level warm-core formation to the CB. Nevertheless, CBs act to be more efficient PV generators due to their vigorous latent heat release and are thus favorable for RI.

scholarly journals Axisymmetric Potential Vorticity Evolution of Hurricane Patricia (2015)

2019 ◽  
Vol 76 (7) ◽  
pp. 2043-2063 ◽  
Author(s):  
Jonathan Martinez ◽  
Michael M. Bell ◽  
Robert F. Rogers ◽  
James D. Doyle
Keyword(s):  
Tropical Cyclone ◽  
Potential Vorticity ◽  
Doppler Radar ◽  
Numerical Models ◽  
Naval Research ◽  
Forecast Errors ◽  
Rapid Intensification ◽  
Mixing Processes ◽  
Large Intensity ◽  
Isentropic Coordinates

Abstract Operational numerical models failed to predict the record-setting rapid intensification and rapid overwater weakening of Hurricane Patricia (2015) in the eastern North Pacific basin, resulting in large intensity forecast errors. In an effort to better understand the mesoscale processes contributing to Patricia’s rapid intensity changes, we analyze high-resolution aircraft observations collected on 22–23 October. Spline-based variational analyses are created from observations collected via in situ measurements, Doppler radar, and full-tropospheric dropsonde profiles as part of the Office of Naval Research Tropical Cyclone Intensity (TCI) experiment and the National Oceanic and Atmospheric Administration Intensity Forecasting Experiment (IFEX). We present the first full-tropospheric calculation of the dry, axisymmetric Ertel’s potential vorticity (PV) in a tropical cyclone without relying on balance assumptions. Detailed analyses reveal the formation of a “hollow tower” PV structure as Patricia rapidly approached its maximum intensity, and a subsequent breakdown of this structure during Patricia’s rapid overwater weakening phase. Transforming the axisymmetric PV analyses from radius–height to potential radius–isentropic coordinates reveals that Patricia’s rapid intensification was closely related to the distribution of diabatic heating and eddy mixing. During Patricia’s rapid overwater weakening phase, eddy mixing processes are hypothesized to be the primary factor rearranging the PV distribution near the eye–eyewall region, diluting the PV previously confined to the hollow tower while approximately conserving the absolute circulation.

Prediction of rapid intensification of tropical cyclonePhailinover the Bay of Bengal using the HWRF modelling system

2017 ◽  
Vol 143 (703) ◽  
pp. 678-690 ◽  
Author(s):  
Krishna K. Osuri ◽  
Raghu Nadimpalli ◽  
Uma C. Mohanty ◽  
Dev Niyogi
Keyword(s):  
Bay Of Bengal ◽  
Rapid Intensification ◽  
Modelling System

The role of ENSO and MJO on rapid intensification of tropical cyclones in the Bay of Bengal during October–December

2014 ◽  
Vol 120 (3-4) ◽  
pp. 797-810 ◽  
Author(s):  
M. S. Girishkumar ◽  
K. Suprit ◽  
S. Vishnu ◽  
V. P. Thanga Prakash ◽  
M. Ravichandran
Keyword(s):  
Tropical Cyclones ◽  
Bay Of Bengal ◽  
Rapid Intensification

scholarly journals Intensity fluctuations in Hurricane Irma (2017) during a period of rapid intensification

2022 ◽  
Author(s):  
William Stanley Torgerson ◽  
Juliane Schwendike ◽  
Andrew Ross ◽  
Chris Short
Keyword(s):  
Boundary Layer ◽  
Tropical Cyclone ◽  
Vertical Velocity ◽  
Potential Vorticity ◽  
Relative Vorticity ◽  
Rapid Intensification ◽  
Intensity Fluctuations ◽  
Strengthening Phases ◽  
Hurricane Irma ◽  
Vorticity Structure

Abstract. Intensity fluctuations observed during a period of rapid intensification of Hurricane Irma (2017) between 04 September and 06 September were investigated in a detailed modelling study using an ensemble of Met Office Unified Model (MetUM) convection permitting forecasts. These intensity fluctuations consisted of alternating weakening and strengthening phases. During weakening phases the tropical cyclone temporarily paused its intensification. It was found that weakening phases were associated with a change in the potential vorticity structure, with a tendency for it to become more monopolar. Convection during strengthening phases was associated with isolated local regions of high relative vorticity and vertical velocity in the eyewall, while during weakening phases the storm became more azimuthally symmetric with weaker convection spread more evenly. The boundary layer was found to play an important role in the cause of the intensity fluctuations with an increase in the agradient wind within the boundary layer causing a spin--down just above the boundary layer during the weakening phases whereas during the strengthening phases the agradient wind reduces. This study offers new explanations for why these fluctuations occur and what causes them.

Observed Inner-Core Structural Variability in Hurricane Dolly (2008)*

2012 ◽  
Vol 140 (12) ◽  
pp. 4066-4077 ◽  
Author(s):  
Eric A. Hendricks ◽  
Brian D. McNoldy ◽  
Wayne H. Schubert
Keyword(s):  
Vortex Dynamics ◽  
Potential Vorticity ◽  
Wind Shear ◽  
Inner Core ◽  
Deep Layer ◽  
Vertical Wind Shear ◽  
Sea Surface ◽  
Rapid Intensification ◽  
Barotropic Instability ◽  
Structural Variability

Abstract Hurricane Dolly (2008) exhibited dramatic inner-core structural variability during a 6-h rapid intensification and deepening event just prior to making landfall in southern Texas at 1800 UTC 23 July. In particular, the eyewall was highly asymmetric from 0634–1243 UTC, with azimuthal wavenumber m = 4–7 patterns in the eyewall radar reflectivity and prominent mesovortex and polygonal eyewall signatures. Evidence is presented that the most likely cause of the high-wavenumber asymmetries is a convectively modified form of barotropic instability of the thin eyewall potential vorticity ring. The rapid intensification and deepening event occurred while Dolly was in a favorable environment with weak deep-layer vertical wind shear and warm sea surface temperatures; however, the environmental conditions were becoming less favorable during the period of rapid intensification. Therefore, it is plausible that the internal vortex dynamics were dominant contributors to the rapid intensification and deepening.

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