A Statistical Analysis of Steady Eyewall Sizes Associated with Rapidly Intensifying Hurricanes

Qin, Nannan; Zhang, Da‐Lin; Li, Ying

doi:10.1175/waf-d-16-0016.1

Cited by 27 publications

(22 citation statements)

References 33 publications

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“…The rapid slow-down of RMW contraction and the subsequent S-RMW phenomenon are also apparent during the RI of intense TCs, for example, in the simulations of Hurricane Wilma (2005) by Chen et al (2011, hereafter C11), and Typhoon Megi (2010) by Wang and Wang (2014). More recently, Qin et al (2016) carried out a statistical analysis of the S-RMW phenomenon associated with rapidly intensifying hurricanes using 25-year Extended Best Track datasets, in order to see to what extent the S-RMW phenomenon, revealed mostly by TC models, occurs in real storms. They found that about 59% of the RI events at 24 h intervals associated with 55 rapidly intensifying hurricanes exhibited the S-RMW phenomenon, and that the S-RMW tends to occur more commonly in more intense hurricanes (i.e.…”

Section: Introductionmentioning

confidence: 94%

“…This result is consistent with the statistical analysis of Qin et al . (), who showed that RI processes are not always accompanied by contracting RMW, and that the S‐RMW is found more frequently in intense storms and in storms with small RMW.…”

Section: Spatio‐temporal Vortex Structures During Rimentioning

confidence: 99%

“…More recently, Qin et al . () carried out a statistical analysis of the S‐RMW phenomenon associated with rapidly intensifying hurricanes using 25‐year Extended Best Track datasets, in order to see to what extent the S‐RMW phenomenon, revealed mostly by TC models, occurs in real storms. They found that about 59% of the RI events at 24 h intervals associated with 55 rapidly intensifying hurricanes exhibited the S‐RMW phenomenon, and that the S‐RMW tends to occur more commonly in more intense hurricanes (i.e.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the rapid intensification of Hurricane Wilma (2005). Part IV: Inner‐core dynamics during the steady radius of maximum wind stage

Qin

Zhang

Miller

et al. 2018

Quart J Royal Meteoro Soc

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Recent studies show that some hurricanes may undergo rapid intensification (RI) without contracting the radius of maximum wind (RMW). A cloud‐resolving mesoscale model prediction of Hurricane Wilma (2005) is used herein to examine what controls the RMW contraction and how a hurricane could undergo RI without contraction. Results show that the processes controlling the RMW contraction are different within and above the planetary boundary layer (PBL). In the PBL, radial inflow contributes to contraction, whereas frictional dissipation acts as an inhibiting factor. Above the PBL, radial outflow and vertical motion are the two main factors governing the RMW contraction, with the former inhibiting it. A budget analysis of absolute angular momentum (AAM) shows that the radial AAM flux convergence is the major process accounting for the spin‐up of the maximum rotation in the PBL as the RMW contracts, while the vertical flux divergence of AAM and the friction oppose the spin‐up. During the RI stage with no RMW contraction, the local AAM tendencies in the eyewall are however smaller in magnitude and narrower in width than those during the contracting RI stage. In addition, the AAM following the time‐dependent RMW decreases with time in the PBL and remains nearly constant aloft during the contracting stage, whereas it increases during the non‐contracting stage. These results reveal different constraints for the RMW contraction and RI, and help explain why a hurricane vortex can still intensify after the RMW ceases contraction.

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Section: Introductionmentioning

confidence: 94%

Section: Spatio‐temporal Vortex Structures During Rimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the rapid intensification of Hurricane Wilma (2005). Part IV: Inner‐core dynamics during the steady radius of maximum wind stage

Qin

Zhang

Miller

et al. 2018

Quart J Royal Meteoro Soc

Self Cite

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“…However, the result here is consistent with recent findings by Qin et al . [], who reported that the RI phase of TCs often occurred with constant RMWs after the rapid contraction. Since our main interest in this study was to evaluate the contribution of the near‐surface high energy air in the eye region to the intensification rate of the simulated TC, we focused on the RI phase and artificially modified the exchange coefficient for surface entropy flux calculation in the eye region after the first 36 h spinup period.…”

Section: Intensity Evolution Of the Simulated Stormsmentioning

confidence: 99%

Contribution of eye excess energy to the intensification rate of tropical cyclones: A numerical study

Wang

Heng

2016

J Adv Model Earth Syst

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Contribution of the near‐surface high energy air in the eye region to tropical cyclone (TC) intensification rate (IR) has been evaluated based on idealized numerical experiments using a cloud‐resolving, nonhydrostatic atmospheric model. The results show that when the surface entropy flux was turned off in the eye region, the equivalent potential temperature and convective available potential energy in the eye were largely suppressed while the IR of the simulated storm was reduced by about 30% in the rapid intensification (RI) phase. This suggests that the near‐surface high energy air in the eye region contributed about 42% to the IR of the simulated storm. The results also showed that the number of convective bursts and the rainfall rate averaged in the inner‐core region did not display significant differences. This suggests that the effect of the near‐surface high energy air in the eye region on the simulated TC IR was not through the modifications to the overall strength of eyewall convection as previously hypothesized. It is found that the removal of surface entropy flux in the eye region resulted in a slower eyewall contraction and the larger radius of maximum wind (RMW). The results suggest that the near‐surface high energy air in the eye region can initiate convection near the inner edge of the eyewall and facilitates eyewall contraction, leading to higher inner‐core inertial stability and thus higher dynamical efficiency of eyewall heating in spinning up the tangential winds near the RMW and larger IR of the simulated TC.

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“…Updrafts and downdrafts are highly concentrated within the eyewall, which is a ring surrounding the TC eye that comprises towering convective systems responsible for the most severe weather including the strongest winds (Aberson et al, ; Foerster et al, ). The intensification/weakening of a TC is usually accompanied by the variation of eyewall structure (Qin et al, ; Sitkowski et al, ). For example, the eyewall is established with a cycle of TC intensification and is broken down with a cycle of weakening (Wang, ).…”

Section: Introductionmentioning

confidence: 99%

Vertical Motions Prior to the Intensification of Simulated Typhoon Hagupit (2008)

Chen

Wen

et al. 2019

JGR Oceans

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Signals prior to tropical cyclone (TC) intensification are important for improving TC intensity forecasts. The existence of such signals has been noted in previous studies of satellite-borne observations and lightning. Vertical motions can enhance TCs via the transportation of heat to the warm core; thus, we hypothesized they might signal TC intensification. This study separately examined the processes of updrafts and downdrafts, which are both concentrated within the eyewall surrounding the warm core. The analysis focused on the intensification of Typhoon Hagupit (2008). Numerical experiments were conducted using the Weather Research and Forecasting model to elucidate the changing structure of the vertical motions and their effects on the timing of TC intensification. A control (CTL) simulation and an idealized No-Land experiment both reproduced the storm structure well, whereas a Half-Bogus (Half-Moisture) experiment generated less-organized TC core structures (weakened moisture convection). Upward motions were found to signal TC intensification with lead times of 1.67-4.50 hr in all experiments. Downward motions apparently signaled TC intensification with lead times of 0.67-4.50 hr in the Half-Bogus and Half-Moisture experiments. However, the lead-lag relationship between downward motion and TC intensification was unclear in the CTL and No-Land experiments because of the large amount of water vapor in the enhanced eyewall. Thermodynamic analysis showed the latent heat consumed in the downdrafts in the CTL and No-Land experiments was much greater than in the two other experiments, which resulted in the smallest heating contribution in the downdrafts and a weak relationship with TC intensification.Plain Language Summary We believe that everyone can forecast the intensification of a tropical cyclone (TC) by the help of some prior signals, thus we tried to find these signals in this study. Vertical motions are the winds that moving upward or downward. They are able to become such prior signals, because they can strengthen the TC through transporting energy to the TC center. We found that the intensification of upward motions occurs <5 hr before the intensification of a TC. This proves the existence of such prior signals and might help to improve the forecast skill of TCs in future.

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A Statistical Analysis of Steady Eyewall Sizes Associated with Rapidly Intensifying Hurricanes

Cited by 27 publications

References 33 publications

On the rapid intensification of Hurricane Wilma (2005). Part IV: Inner‐core dynamics during the steady radius of maximum wind stage

On the rapid intensification of Hurricane Wilma (2005). Part IV: Inner‐core dynamics during the steady radius of maximum wind stage

Contribution of eye excess energy to the intensification rate of tropical cyclones: A numerical study

Vertical Motions Prior to the Intensification of Simulated Typhoon Hagupit (2008)

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