scholarly journals Large-scale characteristics of rapidly intensifying tropical cyclones over the Bay of Bengal and a Rapid Intensification (RI) index

MAUSAM ◽  
2022 ◽  
Vol 64 (1) ◽  
pp. 13-24
Author(s):  
S.D. KOTAL ◽  
S.K.ROY BHOWMIK
Keyword(s):  
Tropical Cyclones ◽  
Bay Of Bengal ◽  
Large Scale ◽  
Rapid Intensification ◽  
Scale Characteristics

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.

Different Climatological Characteristics, Inner-Core Structures, and Intensification Processes of Simulated Intense Tropical Cyclones between 20-km Global and 5-km Regional Models

2017 ◽  
Vol 30 (5) ◽  
pp. 1583-1603 ◽  
Author(s):  
Sachie Kanada ◽  
Akiyoshi Wada
Keyword(s):  
Tropical Cyclones ◽  
General Circulation ◽  
Large Scale ◽  
Atmospheric General Circulation Model ◽  
Inner Core ◽  
Circulation Model ◽  
Maximum Intensity ◽  
Rapid Intensification ◽  
Nonhydrostatic Model ◽  
Before And After

Abstract Climatological characteristics of simulated intense tropical cyclones (TCs) in the western North Pacific were explored with a 20-km-mesh atmospheric general circulation model (AGCM20) and a 5-km-mesh regional atmospheric nonhydrostatic model (ANHM5). From the AGCM20 climate runs, 34 intense TCs with a minimum central pressure (MCP) less than or equal to 900 hPa were sampled. Downscaling experiments were conducted with the ANHM5 for each intense TC simulated by the AGCM20. Only 23 developed into TCs with MCP ≤ 900 hPa. Most of the best-track TCs with an MCP ≤ 900 hPa underwent rapid intensification (RI) and attained maximum intensities south of 25°N. The AGCM20 simulated a similar number of intense TCs as the best-track datasets. However, the intense AGCM20 TCs tended to intensify longer and more gradually; only half of them underwent RI. The prolonged gradual intensification resulted in significant northward shifts of the location of maximum intensity compared with the location derived from two best-track datasets. The inner-core structure of AGCM20 TCs exhibited weak and shallow eyewall updrafts with maxima below an altitude of 6 km, while downscaling experiments revealed that most of the intense ANHM5 TCs underwent RI with deep and intense eyewall updrafts and attained their maximum intensity at lower latitudes. The altitudes of updraft maxima simulated by the AGCM20 descended rapidly during the phase of greatest intensification as midlevel warming markedly developed. The change in major processes responsible for precipitation in AGCM20 TCs before and after maximum intensification suggests close relationships between the large-scale cloud scheme and midlevel warming and prolonged gradual intensification.

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 Premonsoon/Postmonsoon Bay of Bengal Tropical Cyclones Intensity: Role of Air‐Sea Coupling and Large‐Scale Background State

2019 ◽  
Vol 46 (4) ◽  
pp. 2149-2157 ◽  
Author(s):  
S. Neetu ◽  
M. Lengaigne ◽  
J. Vialard ◽  
G. Samson ◽  
S. Masson ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Bay Of Bengal ◽  
Large Scale ◽  
Background State

Large-scale characteristics of landfalling tropical cyclones with abrupt intensity change

2019 ◽  
Vol 13 (4) ◽  
pp. 808-816
Author(s):  
Qianqian Ji ◽  
Feng Xu ◽  
Jianjun Xu ◽  
Mei Liang ◽  
Shifei Tu ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Large Scale ◽  
Intensity Change ◽  
Scale Characteristics ◽  
Landfalling Tropical Cyclones

scholarly journals Large-Scale Characteristics and Probability of Rapidly Intensifying Tropical Cyclones in the Western North Pacific Basin

2012 ◽  
Vol 27 (2) ◽  
pp. 411-423 ◽  
Author(s):  
Shoujuan Shu ◽  
Jie Ming ◽  
Peng Chi
Keyword(s):  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
Large Scale ◽  
Vertical Shear ◽  
Pacific Basin ◽  
China Meteorological Administration ◽  
Scale Characteristics ◽  
Environmental Prediction ◽  
North Pacific Basin

Abstract The China Meteorological Administration (CMA) and the National Centers for Environmental Prediction (NCEP) reanalysis datasets are employed to examine the large-scale characteristics of rapidly intensifying western North Pacific tropical cyclones (TCs). The results show that of all 27 581 samples for the period 1970–2007, 85%, 65%, and 47% of all tropical depressions (TDs), tropical storms (TSs), and typhoons (TYs), respectively, intensify. Of the 1214 TCs, 18%, 70%, 30%, and 10% of all tropical cyclones, supertyphoons, severe typhoons, and typhoons, respectively, underwent rapid intensification (RI) at least once during their lifetime. Three kinds of cases—RI, slow change in intensity (SC), and rapid decay (RD)—during the period 1982–2007 are used to analyze the large-scale conditions associated with them. The comparison shows that the RI cases tend to occur farther south and east than the non-RI cases. In addition, the RI cases have a more westerly component of motion and intensify more during the preceding 12 h than do the non-RI cases. For the non-RI cases, the SC cases tend to have a lower initial intensity and a lower speed of motion than do the RD cases. Also, the RI cases are farther from their maximum potential intensity and develop in warmer water, lower vertical shear, and more easterly upper-tropospheric flow than do the non-RI cases. The probability of RI for TCs is estimated by using the rapid intensify index (RII) developed in this study for the western North Pacific basin. The verification based upon the cross validation shows that the RII is skillful relative to climatology.

scholarly journals Are Special Processes at Work in the Rapid Intensification of Tropical Cyclones?

2015 ◽  
Vol 143 (3) ◽  
pp. 878-882 ◽  
Author(s):  
Roman Kowch ◽  
Kerry Emanuel
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Internal Variability ◽  
Open Ocean ◽  
Rapid Intensification ◽  
Exponential Distributions ◽  
Frequency Distributions ◽  
Fat Tail ◽  
Dissipation Rates ◽  
Special Factors

Abstract Probably not. Frequency distributions of intensification and dissipation developed from synthetic open-ocean tropical cyclone data show no evidence of significant departures from exponential distributions, though there is some evidence for a fat tail of dissipation rates. This suggests that no special factors govern high intensification rates and that tropical cyclone intensification and dissipation are controlled by statistically random environmental and internal variability.

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