The role of diabatic heating, torques and stabilities in forcing the radial-vertical circulation within cyclones part ii: case study of extratropical and tropical cyclones

1998 ◽  
Vol 15 (4) ◽  
pp. 447-488 ◽  
Author(s):  
Zhuojian Yuan ◽  
Donald R. Johnson
Keyword(s):  
Tropical Cyclones ◽  
Diabatic Heating ◽  
Vertical Circulation

Tropical Cyclogenesis Associated with Kelvin Waves and the Madden–Julian Oscillation

2011 ◽  
Vol 139 (9) ◽  
pp. 2723-2734 ◽  
Author(s):  
Carl J. Schreck ◽  
John Molinari
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
Diabatic Heating ◽  
Kelvin Waves ◽  
Tropical Cyclogenesis ◽  
Madden Julian Oscillation ◽  
Convective Envelope

The Madden–Julian oscillation (MJO) influences tropical cyclone formation around the globe. Convectively coupled Kelvin waves are often embedded within the MJO, but their role in tropical cyclogenesis remains uncertain. This case study identifies the influences of the MJO and a series of Kelvin waves on the formation of two tropical cyclones. Typhoons Rammasun and Chataan developed in the western North Pacific on 28 June 2002. Two weeks earlier, conditions had been unfavorable for tropical cyclogenesis because of uniform trade easterlies and a lack of organized convection. The easterlies gave way to equatorial westerlies as the convective envelope of the Madden–Julian oscillation moved into the region. A series of three Kelvin waves modulated the development of the westerlies. Cyclonic potential vorticity (PV) developed in a strip between the growing equatorial westerlies and the persistent trade easterlies farther poleward. Rammasun and Chataan emerged from the apparent breakdown of this strip. The cyclonic PV developed in association with diabatic heating from both the MJO and the Kelvin waves. The tropical cyclones also developed during the largest superposition of equatorial westerlies from the MJO and the Kelvin waves. This chain of events suggests that the MJO and the Kelvin waves each played a role in the development of Rammasun and Chataan.

scholarly journals Evidence for the role of the diabatic heating in synoptic scale processes: a case study example

1997 ◽  
Vol 15 (4) ◽  
pp. 487-493 ◽  
Author(s):  
M. L. Martin ◽  
M. Y. Luna ◽  
F. Valero
Keyword(s):  
Diabatic Heating ◽  
Potential Temperature ◽  
Principal Component ◽  
Phase Changes ◽  
Synoptic Scale ◽  
Thermodynamic Variable ◽  
Dynamic Forcing ◽  
Diabatic Forcing

Abstract. The quasigeostrophic theory is used to address the role of diabatic forcing in synoptic scale processes over Iberia. A parametrization of diabatic heating is obtained in terms of a thermodynamic variable called the ice-liquid water potential temperature which is conservative under all phase changes of water. A case study objectively selected by means of a rotated principal component analysis over the diabatic field is analyzed to test the proposed parametrization. This study highlights the fact that the magnitudes of diabatic forcing and dynamic forcing are very nearly the same throughout the troposphere. The results also show that the composite diabatic heating is a better representation for both cloudiness and precipitation fields than the dynamic forcing.

Forecasting Challenges Associated with Tropical Cyclones within Subtropical Gyres

2014 ◽  
Vol 29 (1) ◽  
pp. 99-114 ◽  
Author(s):  
Brian Crandall ◽  
John Molinari ◽  
David Vollaro
Keyword(s):  
Tropical Cyclones ◽  
Tropical Storm ◽  
Temperature Gradients ◽  
Subtropical Gyre ◽  
Northwest Pacific ◽  
The North ◽  
History Of ◽  
Joint Typhoon Warning Center

Abstract This case study examines the complex history of a tropical storm that formed southeast of a large subtropical gyre. In real time the tropical storm was incorrectly identified as being two separate storms, and at one time was mislocated by 465 km. The unique forecast problems associated with tropical cyclones within a subtropical gyre are described. The tropical storm propagated around the gyre and encountered a midlevel temperature gradient to the north. The interaction of the storm with this gradient produced a strong midtropospheric temperature dipole. Temperature advection within this feature produced a change in structure to a subtropical storm corotating with an upper low. The subtropical storm turned equatorward and nearly came to a halt as the upper low became aligned with the storm. As convection increased over warm water, the upper low shifted away from the center and the storm reversed direction and moved poleward. These sudden track changes have frequently been observed in the northwest Pacific, but the role of midtropospheric temperature gradients has not previously been addressed. Clear air at the gyre center coincided with a region of cold advection. A fishhook structure in the gyre cloudiness developed as a result of warm advection east and north of the gyre. The subtropical structure of the storm evolved within the fishhook. It is recommended that the Joint Typhoon Warning Center (JTWC) provide formal warnings on subtropical storms, because their baroclinic nature can produce dramatic track changes associated with the presence of upper lows near the center.

The role of multiplicity in a cult: A case study

1987 ◽  
Author(s):  
William A. Worrall ◽  
Ann W. Stockman

Endangered Butterflies and their Non-Native Host Plants: Examining Shifting Values of Belonging in Restoration

2019 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Robert M. Anderson ◽  
Amy M. Lambert
Keyword(s):  
Ecological Restoration ◽  
Native Species ◽  
Puget Sound ◽  
A Value ◽  
The Social ◽  
Remote Island ◽  
Scientific Truth ◽  
Native Host

The island marble butterfly (Euchloe ausonides insulanus), thought to be extinct throughout the 20th century until re-discovered on a single remote island in Puget Sound in 1998, has become the focus of a concerted protection effort to prevent its extinction. However, efforts to “restore” island marble habitat conflict with efforts to “restore” the prairie ecosystem where it lives, because of the butterfly’s use of a non-native “weedy” host plant. Through a case study of the island marble project, we examine the practice of ecological restoration as the enactment of particular norms that define which species are understood to belong in the place being restored. We contextualize this case study within ongoing debates over the value of “native” species, indicative of deep-seated uncertainties and anxieties about the role of human intervention to alter or manage landscapes and ecosystems, in the time commonly described as the “Anthropocene.” We interpret the question of “what plants and animals belong in a particular place?” as not a question of scientific truth, but a value-laden construct of environmental management in practice, and we argue for deeper reflexivity on the part of environmental scientists and managers about the social values that inform ecological restoration.

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