scholarly journals Erratum to: Relationship between convective bursts and the rapid intensification of Typhoon Mujigae (2015)

2018 ◽  
Vol 19 (7) ◽  
pp. e845
Author(s):  
Xiba Tang ◽  
Fan Ping ◽  
Shuai Yang ◽  
Mengxia Li ◽  
Jing Peng
Keyword(s):  
Rapid Intensification ◽  
Convective Bursts

scholarly journals On the Rapid Intensification of Hurricane Wilma (2005). Part II: Convective Bursts and the Upper-Level Warm Core

2013 ◽  
Vol 70 (1) ◽  
pp. 146-162 ◽  
Author(s):  
Hua Chen ◽  
Da-Lin Zhang
Keyword(s):  
Inner Core ◽  
Static Stability ◽  
Rapid Intensification ◽  
Important Ingredient ◽  
High Resolution Data ◽  
Hurricane Wilma ◽  
Warm Core ◽  
Convective Bursts ◽  
Upper Level ◽  
The Relationship

Abstract Previous studies have focused mostly on the roles of environmental factors in the rapid intensification (RI) of tropical cyclones (TCs) because of the lack of high-resolution data in inner-core regions. In this study, the RI of TCs is examined by analyzing the relationship between an upper-level warm core, convective bursts (CBs), sea surface temperature (SST), and surface pressure falls from 72-h cloud-permitting predictions of Hurricane Wilma (2005) with the finest grid size of 1 km. Results show that both the upper-level inertial stability increases and static stability decreases sharply 2–3 h prior to RI, and that the formation of an upper-level warm core, from the subsidence of stratospheric air associated with the detrainment of CBs, coincides with the onset of RI. It is found that the development of CBs precedes RI, but most subsidence warming radiates away by gravity waves and storm-relative flows. In contrast, many fewer CBs occur during RI, but more subsidence warming contributes to the balanced upper-level cyclonic circulation in the warm-core (as intense as 20°C) region. Furthermore, considerable CB activity can still take place in the outer eyewall as the storm weakens during its eyewall replacement. A sensitivity simulation, in which SSTs are reduced by 1°C, shows pronounced reductions in the upper-level warm-core intensity and CB activity. It is concluded that significant CB activity in the inner-core regions is an important ingredient in generating the upper-level warm core that is hydrostatically more efficient for the RI of TCs, given all of the other favorable environmental conditions.

scholarly journals Relationship between convective bursts and the rapid intensification of Typhoon Mujigae (2015)

2018 ◽  
Vol 19 (4) ◽  
pp. e811 ◽  
Author(s):  
Xiba Tang ◽  
Fan Ping ◽  
Shuai Yang ◽  
Mengxia Li ◽  
Jing Peng
Keyword(s):  
Rapid Intensification ◽  
Convective Bursts

Rapid intensification of tropical cyclones: Vortex waves seeded by aurorally-generated atmospheric gravity waves?

2020 ◽  
Author(s):  
Lidia Nikitina ◽  
Paul Prikryl ◽  
Shun-Rong Zhang
Keyword(s):  
Solar Wind ◽  
Tropical Cyclones ◽  
Gravity Waves ◽  
Lower Thermosphere ◽  
Lower Atmosphere ◽  
Rapid Intensification ◽  
Mean Flow ◽  
Atmospheric Gravity Waves ◽  
Convective Bursts ◽  
Atmospheric Gravity

<p>Convective bursts have been linked to intensification of tropical cyclones [1]. We consider a possibility of convective bursts being triggered by aurorally-generated atmospheric gravity waves (AGWs) that may play a role in the intensification process of tropical cyclones [2]. A two-dimensional barotropic approximation is used to obtain asymptotic solutions representing propagation of vortex waves [3] launched in tropical cyclones by quasi-periodic convective bursts. The absorption of vortex waves by the mean flow and formation of the secondary eyewall lead to a process of an eyewall replacement cycle that is known to cause changes in tropical cyclone intensity [4]. Rapid intensification of hurricanes and typhoons from 1995-2018 is examined in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system. In support of recently published results [2] it is shown that rapid intensification of TCs tend to follow arrival of high-speed solar wind when the MIA coupling is strongest. The coupling generates internal gravity waves in the atmosphere that propagate from the high-latitude lower thermosphere both upward and downward. In the lower atmosphere, they can be ducted [5] and reach tropical troposphere. Despite their significantly reduced amplitude, but subject to amplification upon over-reflection in the upper troposphere, these AGWs can trigger/release moist instabilities leading to convection and latent heat release. A possibility of initiation of convective bursts by aurorally generated AGWs is investigated. Cases of rapid intensification of recent tropical cyclones provide further evidence to support the published results [2].</p><p>References</p><p>[1] Steranka et al., Mon. Weather Rev., 114, 1539-1546, 1986.</p><p>[2] Prikryl et al., J. Atmos. Sol.-Terr. Phys., 2019.</p><p>[3] Nikitina L.V., Campbell L.J., Stud. Appl. Math., 135, 377–446, 2015.</p><p>[4] Willoughby H.E., et al., J. Atmos. Sci., 39, 395–411, 1982.</p><p>[5] Mayr H.G., et al., J. Geophys. Res., 89, 10929–10959, 1984.</p>

scholarly journals Vertical Velocity and Microphysical Distributions Related to Rapid Intensification in a Simulation of Hurricane Dennis (2005)

2012 ◽  
Vol 69 (12) ◽  
pp. 3515-3534 ◽  
Author(s):  
Greg M. McFarquhar ◽  
Brian F. Jewett ◽  
Matthew S. Gilmore ◽  
Stephen W. Nesbitt ◽  
Tsung-Lin Hsieh
Keyword(s):  
Vertical Velocity ◽  
Model Simulation ◽  
Weather Research And Forecasting ◽  
Rapid Intensification ◽  
Latent Heating ◽  
Replicated Data ◽  
Convective Bursts ◽  
Before And After ◽  
Hurricane Dennis ◽  
Upward Flux

Abstract A 1-km Weather Research and Forecasting model simulation of Hurricane Dennis was used to identify precursors in vertical velocity and latent heating distributions to rapid intensification (RI). Although the observed structure qualitatively replicated data obtained during P-3 and Earth Resources-2 (ER-2) flights, the simulated reflectivity was overestimated. During the 6 h preceding RI, defined as 0000 UTC 8 July 2005 close to the time of simulated maximum central pressure deepening, the asymmetric convection transformed into an eyewall with the maximum 10-m wind speed increasing by 16 m s−1. Contour by frequency altitude diagrams showed unique changes in the breadth of simulated vertical velocity (w) distributions before and after RI. Outliers of w distributions at 14 km preceded RI onset, whereas the increase in w outliers at 6 km lagged it. Prior to RI there was an increase in the upward flux of hydrometeors between 10 and 15 km, with increased contributions from w > 6 m s−1. Increases in lower-level updraft airmass fluxes did not lead RI, but the 14-km positive w outliers were better indicators of RI onset than positive w averages. The area of convective bursts did not strongly increase before RI, but it continually increased after RI. Latent heating was dominated by contributions from w < 2 m s−1, meaning increases in positive w outliers before RI did not cause the increase in latent heating seen during RI. The location of convective bursts and outliers of positive and negative w distributions contracted toward the eye as the simulated Dennis intensified.

scholarly journals Convective-Scale Structure and Evolution during a High-Resolution Simulation of Tropical Cyclone Rapid Intensification

2010 ◽  
Vol 67 (1) ◽  
pp. 44-70 ◽  
Author(s):  
Robert Rogers
Keyword(s):  
Mass Flux ◽  
Inner Core ◽  
Mesoscale Model ◽  
Model Simulation ◽  
Scale Structure ◽  
Convective Precipitation ◽  
Structure Evolution ◽  
Rapid Intensification ◽  
Convective Bursts ◽  
Convective Scale

Abstract The role of convective-scale processes in a 1.67-km mesoscale model simulation of the rapid intensification (RI) of Hurricane Dennis (2005) is presented. The structure and evolution of inner-core precipitating areas during RI, the statistical properties of precipitation during times experiencing vigorous convection (termed convective bursts here) and how they differ from nonburst times, possible differences in convective bursts associated with RI and those not associated with RI, and the impacts of precipitation morphology on the vortex-scale structure and evolution during RI are all examined. The onset of RI is linked to an increase in the areal extent of convective precipitation in the inner core, while the inner-core stratiform precipitating area remains unchanged and the intensity increases only after RI has begun. RI is not tied to a dramatic increase in the number of convective bursts nor in the characteristics of the bursts, such as burst intensity. Rather, the immediate cause of RI is a significant increase in updraft mass flux, particularly in the lowest 1.5 km. This increase in updraft mass flux is accomplished primarily by updrafts on the order of 1–2 m s−1, representing the bulk of the vertical motion distribution. However, a period of enhanced updraft mass flux in the midlevels by moderate to strong (>5 m s−1) updrafts located inside the radius of maximum winds occurs ∼6 h prior to RI, indicating a synergistic relationship between convective bursts and the background secondary circulation prior to RI. This result supports the assertion that both buoyantly driven updrafts and slantwise near-neutral ascent are important features in eyewall structure, evolution, and intensification, including RI.

scholarly journals Multiscale Observations of Hurricane Dennis (2005): The Effects of Hot Towers on Rapid Intensification

2010 ◽  
Vol 67 (3) ◽  
pp. 633-654 ◽  
Author(s):  
Stephen R. Guimond ◽  
Gerald M. Heymsfield ◽  
F. Joseph Turk
Keyword(s):  
Doppler Radar ◽  
Tangential Velocity ◽  
Mature Stage ◽  
Rapid Intensification ◽  
Large Shift ◽  
Warm Core ◽  
Convective Bursts ◽  
Hurricane Dennis ◽  
Flight Level ◽  
Balanced Dynamics

Abstract A synthesis of remote sensing and in situ observations throughout the life cycle of Hurricane Dennis (2005) during the NASA Tropical Cloud Systems and Processes (TCSP) experiment is presented. Measurements from the ER-2 Doppler radar (EDOP), the Advanced Microwave Sounding Unit (AMSU), airborne radiometer, and flight-level instruments are used to provide a multiscale examination of the storm. The main focus is an episode of deep convective bursts (“hot towers”) occurring during a mature stage of the storm and preceding a period of rapid intensification (11-hPa pressure drop in 1 h 35 min). The vigorous hot towers penetrated to 16-km height, had maximum updrafts of 20 m s−1 at 12–14-km height, and possessed a strong transverse circulation through the core of the convection. Significant downdrafts (maximum of 10–12 m s−1) on the flanks of the updrafts were observed, with their cumulative effects hypothesized to result in the observed increases in the warm core. In one ER-2 overpass, subsidence was transported toward the eye by 15–20 m s−1 inflow occurring over a deep layer (0.5–10 km) coincident with a hot tower. Fourier analysis of the AMSU satellite measurements revealed a large shift in the storm’s warm core structure, from asymmetric to axisymmetric, ∼12 h after the convective bursts began. In addition, flight-level wind calculations of the axisymmetric tangential velocity and inertial stability showed a contraction of the maximum winds and an increase in the stiffness of the vortex, respectively, after the EDOP observations. The multiscale observations presented here reveal unique, ultra-high-resolution details of hot towers and their coupling to the parent vortex, the balanced dynamics of which can be generally explained by the axisymmetrization and efficiency theories.

scholarly journals A Study on the Asymmetric Rapid Intensification of Hurricane Earl (2010) Using the HWRF System

2015 ◽  
Vol 72 (2) ◽  
pp. 531-550 ◽  
Author(s):  
Hua Chen ◽  
Sundararaman G. Gopalakrishnan
Keyword(s):  
Cooperative Interaction ◽  
Rapid Intensification ◽  
Low Level ◽  
Convective Bursts ◽  
Forecast Data ◽  
Convective Scale ◽  
Storm Center ◽  
Upper Level ◽  
Left Quadrant ◽  
Relative Flow

Abstract In this study, the results of a forecast from the operational Hurricane Weather Research and Forecast (HWRF) system for Hurricane Earl (2010) are verified against observations and analyzed to understand the asymmetric rapid intensification of a storm in a sheared environment. The forecast verification shows that HWRF captured well Earl’s observed evolution of intensity, convection asymmetry, wind field asymmetry, and vortex tilt in terms of magnitude and direction in the pre rapid and rapid intensification (RI) stages. Examination of the high-resolution forecast data reveals that the tilt was large at the RI onset and decreased quickly once RI commenced, suggesting that vertical alignment is the result instead of the trigger for RI. The RI onset is associated with the development of upper-level warming in the eye, which results from upper-level storm-relative flow advecting the warm air caused by subsidence warming in the upshear-left region toward the low-level storm center. This scenario does not occur until persistent convective bursts (CB) are concentrated in the downshear-left quadrant. The temperature budget calculation indicates that horizontal advection plays an important role in the development of upper-level warming in the early RI stage. The upper-level warming associated with the asymmetric intensification process occurs by means of the cooperative interaction of the convective-scale subsidence, resulting from CBs in favored regions and the shear-induced mesoscale subsidence. When CBs are concentrated in the downshear-left and upshear-left quadrants, the subsidence warming is maximized upshear and then advected toward the low-level storm center by the storm-relative flow at the upper level. Subsequently, the surface pressure falls and RI occurs.

On the Rapid Intensification of Hurricane Wilma (2005). Part III: Effects of Latent Heat of Fusion

2015 ◽  
Vol 72 (10) ◽  
pp. 3829-3849 ◽  
Author(s):  
William Miller ◽  
Hua Chen ◽  
Da-Lin Zhang
Keyword(s):  
Latent Heat ◽  
Inner Core ◽  
Vertical Motion ◽  
Heat Of Fusion ◽  
Rapid Intensification ◽  
Latent Heat Of Fusion ◽  
Hurricane Wilma ◽  
Convective Bursts ◽  
Upper Level ◽  
Reduced Rate

Abstract The impacts of the latent heat of fusion on the rapid intensification (RI) of Hurricane Wilma (2005) are examined by comparing a 72-h control simulation (CTL) of the storm to a sensitivity simulation in which the latent heat of deposition is reduced by removing fusion heating (NFUS). Results show that, while both storms undergo RI, the intensification rate is substantially reduced in NFUS. At peak intensity, NFUS is weaker than CTL by 30 hPa in minimum central pressure and by 12 m s−1 in maximum surface winds. The reduced rate of surface pressure falls in NFUS appears to result hydrostatically from less upper-level warming in the eye. It is shown that CTL generates more inner-core convective bursts (CBs) during RI, with higher altitudes of peak vertical motion in the eyewall, compared to NFUS. The latent heat of fusion contributes positively to sufficient eyewall conditional instability to support CB updrafts. Slantwise soundings taken in CB updraft cores reveal moist adiabatic lapse rates until 200 hPa, where the updraft intensity peaks. These results suggest that CBs may impact hurricane intensification by inducing compensating subsidence of the lower-stratospheric air, and the authors conclude that the development of more CBs inside the upper-level radius of maximum wind and at the higher altitude of latent heating all appear to be favorable for the RI of Wilma.

scholarly journals Multiscale Structure and Evolution of Hurricane Earl (2010) during Rapid Intensification

2015 ◽  
Vol 143 (2) ◽  
pp. 536-562 ◽  
Author(s):  
Robert F. Rogers ◽  
Paul D. Reasor ◽  
Jun A. Zhang
Keyword(s):  
Late Stage ◽  
Early Stage ◽  
Vertical Shear ◽  
Convective System ◽  
Asymmetric Distribution ◽  
Rapid Intensification ◽  
Convective Bursts ◽  
Upper Level ◽  
Two Stages

Abstract The structure and evolution of Hurricane Earl (2010) during its rapid intensification as sampled by aircraft is studied here. Rapid intensification occurs in two stages. During the early stage, covering ~24 h, Earl was a tropical storm experiencing moderate northeasterly shear with an asymmetric distribution of convection, and the symmetric structure was shallow, broad, and diffuse. The upper-level circulation center was significantly displaced from the lower-level circulation at the beginning of this stage. Deep, vigorous convection—termed convective bursts—was located on the east side of the storm and appeared to play a role in positioning the upper-level cyclonic circulation center above the low-level center. By the end of this stage the vortex was aligned and extended over a deep layer, and rapid intensification began. During the late stage, rapid intensification continued as Earl intensified ~20 m s−1 during the next 24 h. The vortex remained aligned in the presence of weaker vertical shear, although azimuthal asymmetries persisted that were characteristic of vortices in shear. Convective bursts concentrated near the radius of maximum winds, with the majority located inside the radius of maximum winds. Each of the two stages described here raises questions about the role of convective- and vortex-scale processes in rapid intensification. During the early stage, the focus is on the role of convective bursts and their associated mesoscale convective system on vortex alignment and the onset of rapid intensification. During the late stage, the focus is on the processes that explain the observed radial distribution of convective bursts that peak inside the radius of maximum winds.

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