Interaction between dynamics and thermodynamics during tropical cyclogenesis

Gjorgjievska, Saska; Raymond, David J.

doi:10.5194/acp-14-3065-2014

Cited by 55 publications

(64 citation statements)

References 34 publications

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“…Our offered hypothesis of Gaston's non-redevelopment described above stands somewhat in contrast to the alternative hypothesis by Gjorgjievska and Raymond (2014). The data shown herein support the view that dry air penetrated the pouch before the first flight into ex-Gaston and disrupted the amplification of vorticity at those levels where dry air intruded.…”

Section: Implications Of Dry Air and A Degraded Pouchcontrasting

confidence: 56%

Why did the storm ex-Gaston (2010) fail to redevelop during the PREDICT experiment?

et al. 2016

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Abstract. An analysis is presented of the failed redevelopment of ex-Gaston during the 2010 PREDICT field campaign based on the European Centre for Medium Range Weather Forecast (ECMWF) analyses. We analyze the dynamics and kinematics of ex-Gaston to investigate the role of dry, environmental air in the failed redevelopment. The flow topology defined by the calculation of particle trajectories shows that ex-Gaston's pouch was vulnerable to dry, environmental air on all days of observations. As early as 12:00 UTC 2 September 2010, a dry layer at and above 600 hPa results in a decrease in the vertical mass flux and vertical relative vorticity. These findings support the hypothesis that entrained, dry air near 600 hPa thwarted convective updraughts and vertical mass flux, which in turn led to a reduction in vorticity and a compromised pouch at these middle levels. A compromised pouch allows further intrusion of dry air and quenching of subsequent convection, therefore hindering vorticity amplification through vortex tube stretching. This study supports recent work investigating the role of dry air in moist convection during tropical cyclogenesis.

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Section: Implications Of Dry Air and A Degraded Pouchcontrasting

confidence: 56%

Why did the storm ex-Gaston (2010) fail to redevelop during the PREDICT experiment?

et al. 2016

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Section: Discussionmentioning

confidence: 70%

“…In fact, for several cases analyzed by Raymond et al (2011) and Gjorgjievska and Raymond (2014) that were observed over multiple days (including TCS025), the calculated vorticity tendency was opposite in sign to the observed trend. Gjorgjievska and Raymond (2014) also point out that a mass flux analysis may be even more sensitive to sampling biases since calculation of the average vertical velocity profile relies on shorter time scales and smaller horizontal scales of motion. For instance, our analysis of average dropwindsonde temperature anomaly profiles did not indicate a clear trend of increasing stabilization that might be expected based on the bottom-heavy mass flux profile found by Raymond et al (2011) during IOP-3.…”

Section: Discussionmentioning

confidence: 70%

“…However, as Gjorgjievska and Raymond (2014) point out, a vorticity tendency analysis only provides a snapshot, and may not represent the longer-term evolution of a system. In fact, for several cases analyzed by Raymond et al (2011) and Gjorgjievska and Raymond (2014) that were observed over multiple days (including TCS025), the calculated vorticity tendency was opposite in sign to the observed trend.…”

Section: Discussionmentioning

confidence: 99%

“…Raymond and Sessions (2007), Raymond et al (2011), and Gjorgjievska and Raymond (2014) have suggested that a vertical mass flux maximum in the low levels, or a ''bottom-heavy'' mass flux profile, is most conducive for storm formation through the horizontal flux convergence of low-level vorticity (i.e., low-level spinup), and that a stabilization of the thermodynamic profile results in lowering the level of maximum vertical mass flux. Davis andAhijevych (2012, 2013) found evidence of this stabilization from dropwindsonde data collected during the Pre-Depression Investigation of Cloudsystems in the Tropics (PREDICT) field experiment , as low-level cooling occurred prior to storm formation for two developing systems.…”

Section: Introductionmentioning

confidence: 99%

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Observations of a Nondeveloping Tropical Disturbance in the Western North Pacific during TCS-08 (2008)

Penny

Harr

Bell

2015

Monthly Weather Review

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Large uncertainty still remains in determining whether a tropical cloud cluster will develop into a tropical cyclone. During The Observing System Research and Predictability Experiment (THORPEX) Pacific Asian Regional Campaign (T-PARC)/Tropical Cyclone Structure-2008 (TCS-08) field experiment, over 50 tropical cloud clusters were monitored for development, but only 4 developed into a tropical cyclone. One nondeveloping tropical disturbance (TCS025) was closely observed for potential formation during five aircraft research missions, which provided an unprecedented set of observations pertaining to the large-scale and convective environments of a nondeveloping system. The TCS025 disturbance was comprised of episodic convection that occurred in relation to the diurnal cycle along the eastern extent of a broad low-level trough. The upper-level environment was dominated by two cyclonic cells in the tropical upper-tropospheric trough (TUTT) north of the low-level trough in which the TCS025 circulation was embedded. An in-depth examination of in situ observations revealed that the nondeveloping circulation was asymmetric and vertically misaligned, which led to larger system-relative flow on the mesoscale. Persistent environmental vertical wind shear and horizontal shearing deformation near the circulation kept the system from becoming better organized and appears to have allowed low equivalent potential temperature (u e ) air originating from one of the TUTT cells to the north (upshear) to impact the thermodynamic environment of TCS025. This in turn weakened subsequent convection that might otherwise have improved alignment and contributed to the transition of TCS025 to a tropical cyclone.

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Anomaly patterns about strong convective events in the tropics and midlatitudes: Observations from radiosondes and surface weather stations

Mitovski

Folkins

2014

JGR Atmospheres

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We use 13 years (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) of rainfall estimates from the Tropical Rainfall Measuring Mission to identify high rain events located close to radiosondes. This is done in four regions: the Western Tropical Pacific, Tropical Brazil, Southeast China, and Southeast U.S. We then construct composite anomaly patterns of temperature, relative humidity, surface pressure, convective available potential energy (CAPE), geopotential height, mass divergence, relative vorticity, and potential vorticity about these high rain events. One motivation of this analysis is to identify regional differences in the interaction between strong convective events and the background atmosphere. We find, overall, that the changes in meteorological variables which occur during the evolution of strong convective events in midlatitudes are similar to the changes that occur in the tropics. In midlatitudes, however, strong convective events are associated with stronger anomalies in surface pressure and geopotential height and exhibit a warm anomaly in the lower troposphere prior to peak rainfall. In the Southeast U.S., the near-surface layer of positive CAPE that occurs prior to high rain events is thicker than in the Western Tropical Pacific. In the two midlatitude regions, the midlevel potential vorticity maximum that develops during the growth stage of high rain events acquires a downward tilt toward the surface during the decay stage, suggesting downward transport toward the surface. A conceptual model previously used to interpret the anomaly patterns of the 2 day equatorial wave is used to interpret the anomaly patterns associated with more general types of high rain events in the tropics.

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Interaction between dynamics and thermodynamics during tropical cyclogenesis

Cited by 55 publications

References 34 publications

Why did the storm ex-Gaston (2010) fail to redevelop during the PREDICT experiment?

Why did the storm ex-Gaston (2010) fail to redevelop during the PREDICT experiment?

Observations of a Nondeveloping Tropical Disturbance in the Western North Pacific during TCS-08 (2008)

Anomaly patterns about strong convective events in the tropics and midlatitudes: Observations from radiosondes and surface weather stations

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