scholarly journals The Response of Tropical Cyclone Intensity to Temperature Profile Change

2022 ◽  
Author(s):  
James M. Done ◽  
Gary M. Lackmann ◽  
Andreas F. Prein
Keyword(s):  
Tropical Cyclone ◽  
Temperature Profile ◽  
Tropical Cyclones ◽  
Intensity Change ◽  
Tropical Cyclone Intensity ◽  
Vertical Temperature Profile ◽  
Cyclone Intensity ◽  
Stratospheric Temperature ◽  
Stratospheric Cooling ◽  
Profile Change

Abstract. Theory indicates that tropical cyclone intensity should respond to changes in the vertical temperature profile. While the sensitivity of tropical cyclone intensity to sea surface temperature is well understood, less is known about sensitivity to the temperature profile. In this paper, we combine historical data analysis and idealised modelling to explore the extent to which historical tropospheric warming and lower stratospheric cooling can explain observed trends in the tropical cyclone intensity distribution. Observations and modelling agree that historical global temperature profile changes coincide with higher lifetime maximum intensities. But observations suggest the response depends on the tropical cyclone intensity itself. Historical lower- and upper-tropospheric temperatures in hurricane environments have warmed significantly faster than the tropical mean. In addition, hurricane-strength storms have intensified at twice the rate of weaker storms per unit warming at the surface and at 300-hPa. Idealized simulations respond in the expected sense to various imposed changes in the temperature profile and agree with tropical cyclones operating as heat engines. Yet lower stratospheric temperature changes have little influence. Idealised modelling further shows an increasing altitude of the TC outflow but little change in outflow temperature. This enables increased efficiency for strong tropical cyclones despite the warming upper troposphere. Observed sensitivities are generally larger than modelled sensitivities, suggesting that observed tropical cyclone intensity change responds to a combination of the temperature profile change and other environmental factors.

Tropical Cyclone Intensity Change before U.S. Gulf Coast Landfall

2010 ◽  
Vol 25 (5) ◽  
pp. 1380-1396 ◽  
Author(s):  
Edward N. Rappaport ◽  
James L. Franklin ◽  
Andrea B. Schumacher ◽  
Mark DeMaria ◽  
Lynn K. Shay ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Heat Content ◽  
Vertical Wind Shear ◽  
Intensity Change ◽  
Forecast Errors ◽  
Regression Equations ◽  
Least Squares Regression ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity

Abstract Tropical cyclone intensity change remains a forecasting challenge with important implications for such vulnerable areas as the U.S. coast along the Gulf of Mexico. Analysis of 1979–2008 Gulf tropical cyclones during their final two days before U.S. landfall identifies patterns of behavior that are of interest to operational forecasters and researchers. Tropical storms and depressions strengthened on average by about 7 kt for every 12 h over the Gulf, except for little change during their final 12 h before landfall. Hurricanes underwent a different systematic evolution. In the net, category 1–2 hurricanes strengthened, while category 3–5 hurricanes weakened such that tropical cyclones approach the threshold of major hurricane status by U.S. landfall. This behavior can be partially explained by consideration of the maximum potential intensity modified by the environmental vertical wind shear and hurricane-induced sea surface temperature reduction near the storm center associated with relatively low oceanic heat content levels. Linear least squares regression equations based on initial intensity and time to landfall explain at least half the variance of the hurricane intensity change. Applied retrospectively, these simple equations yield relatively small forecast errors and biases for hurricanes. Characteristics of most of the significant outliers are explained and found to be identifiable a priori for hurricanes, suggesting that forecasters can adjust their forecast procedures accordingly.

scholarly journals The Validity of Dvorak Intensity Change Constraints for Tropical Cyclones

2015 ◽  
Vol 30 (4) ◽  
pp. 1010-1015 ◽  
Author(s):  
John P. Cangialosi ◽  
Todd B. Kimberlain ◽  
John L. Beven ◽  
Mark Demaria
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Small Sample ◽  
Intensity Change ◽  
Tropical Storms ◽  
Intensity Analysis ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity

Abstract The Dvorak technique is used operationally worldwide for tropical cyclone intensity analysis. This study tests Dvorak intensity change constraints, using a database of simultaneous aircraft and satellite fixes for tropical cyclones (TCs) in the 1998–2012 period. Results indicate that, in the vast majority of cases, Dvorak intensity constraints are valid with only a small percentage of strengthening TCs violating the constraints. Of the small sample that broke the constraints, most had initial intensities ranging from moderately strong tropical storms to minimal hurricanes.

scholarly journals Forecasting tropical cyclone intensity change in the western North Pacific

2013 ◽  
Vol 15 (3) ◽  
pp. 952-966 ◽  
Author(s):  
Gwo-Fong Lin ◽  
Po-Kai Huang ◽  
Hsuan-Yu Lin
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Intensity Change ◽  
Support Vector ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity ◽  
Complex Process ◽  
Proposed Model ◽  
Vector Machines ◽  
Validation Tests

For typhoon warning centers, effective forecasting of tropical cyclone intensity is always required. The major difficulties and challenges in forecasting tropical cyclone intensity are the complex physical mechanism and the structure of tropical cyclones. The interaction between the tropical cyclone and its environment is also a complex process. In this paper, a model based on support vector machines is developed to yield the 12, 24, 36, 48, 72 h forecasts of tropical cyclone intensity. Furthermore, the forecasts resulting from the proposed model are compared with those from the Joint Typhoon Warning Center. Cross-validation tests are also applied to evaluate the accuracy and the robustness of the proposed model. The results confirm that the proposed model can provide accurate forecasts of tropical cyclone intensity, especially for a long lead-time. When the sample events are classified into five categories according to the Saffir-Simpson scale, the forecasts resulting from the proposed model have the best performance for events in categories 4 and 5. In addition, when a typhoon turns northward, although the water temperature drops rapidly, the proposed model still performs well. In conclusion, the proposed model is useful to improve the forecasts of tropical cyclones intensity.

scholarly journals A View of Tropical Cyclones from Above: The Tropical Cyclone Intensity Experiment

2017 ◽  
Vol 98 (10) ◽  
pp. 2113-2134 ◽  
Author(s):  
James D. Doyle ◽  
Jonathan R. Moskaitis ◽  
Joel W. Feldmeier ◽  
Ronald J. Ferek ◽  
Mark Beaubien ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Lower Stratosphere ◽  
Inner Core ◽  
Horizontal Resolution ◽  
Intensity Change ◽  
Naval Research ◽  
Atmospheric Conditions ◽  
Tropical Cyclone Intensity ◽  
High Definition ◽  
Cyclone Intensity

Abstract Tropical cyclone (TC) outflow and its relationship to TC intensity change and structure were investigated in the Office of Naval Research Tropical Cyclone Intensity (TCI) field program during 2015 using dropsondes deployed from the innovative new High-Definition Sounding System (HDSS) and remotely sensed observations from the Hurricane Imaging Radiometer (HIRAD), both on board the NASA WB-57 that flew in the lower stratosphere. Three noteworthy hurricanes were intensively observed with unprecedented horizontal resolution: Joaquin in the Atlantic and Marty and Patricia in the eastern North Pacific. Nearly 800 dropsondes were deployed from the WB-57 flight level of ∼60,000 ft (∼18 km), recording atmospheric conditions from the lower stratosphere to the surface, while HIRAD measured the surface winds in a 50-km-wide swath with a horizontal resolution of 2 km. Dropsonde transects with 4–10-km spacing through the inner cores of Hurricanes Patricia, Joaquin, and Marty depict the large horizontal and vertical gradients in winds and thermodynamic properties. An innovative technique utilizing GPS positions of the HDSS reveals the vortex tilt in detail not possible before. In four TCI flights over Joaquin, systematic measurements of a major hurricane’s outflow layer were made at high spatial resolution for the first time. Dropsondes deployed at 4-km intervals as the WB-57 flew over the center of Hurricane Patricia reveal in unprecedented detail the inner-core structure and upper-tropospheric outflow associated with this historic hurricane. Analyses and numerical modeling studies are in progress to understand and predict the complex factors that influenced Joaquin’s and Patricia’s unusual intensity changes.

scholarly journals Precipitation Properties Observed during Tropical Cyclone Intensity Change

2015 ◽  
Vol 143 (11) ◽  
pp. 4476-4492 ◽  
Author(s):  
George R. Alvey III ◽  
Jonathan Zawislak ◽  
Edward Zipser
Keyword(s):  
Tropical Cyclone ◽  
Passive Microwave ◽  
Intensity Change ◽  
Rapid Intensification ◽  
Relative Importance ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity ◽  
East Pacific ◽  
Intensity Changes ◽  
Strong Convection

Abstract Using a 15-yr (1998–2012) multiplatform dataset of passive microwave satellite data [tropical cyclone–passive microwave (TC-PMW)] for Atlantic and east Pacific storms, this study examines the relative importance of various precipitation properties, specifically convective intensity, symmetry, and area, to the spectrum of intensity changes observed in tropical cyclones. Analyses are presented not only spatially in shear-relative quadrants around the center, but also every 6 h during a 42-h period encompassing 18 h prior to onset of intensification to 24 h after. Compared to those with slower intensification rates, storms with higher intensification rates (including rapid intensification) have more symmetric distributions of precipitation prior to onset of intensification, as well as a greater overall areal coverage of precipitation. The rate of symmetrization prior to, and during, intensification increases with increasing intensity change as rapidly intensifying storms are more symmetric than slowly intensifying storms. While results also clearly show important contributions from strong convection, it is concluded that intensification is more closely related to the evolution of the areal, radial, and symmetric distribution of precipitation that is not necessarily intense.

scholarly journals Operational Perspectives on Tropical Cyclone Intensity Change Part 1: recent advances in intensity guidance

2019 ◽  
Vol 8 (3) ◽  
pp. 123-133 ◽  
Author(s):  
Joseph B. Courtney ◽  
Sébastien Langlade ◽  
Charles R. Sampson ◽  
John A. Knaff ◽  
Thomas Birchard ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Intensity Change ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity ◽  
Recent Advances

scholarly journals The Advanced Dvorak Technique (ADT) for Estimating Tropical Cyclone Intensity: Update and New Capabilities

2019 ◽  
Vol 34 (4) ◽  
pp. 905-922 ◽  
Author(s):  
Timothy L. Olander ◽  
Christopher S. Velden
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Surface Wind ◽  
Performance Characteristics ◽  
Tropical Cyclone Intensity ◽  
Algorithm Development ◽  
Intensity Estimation ◽  
Development Team ◽  
Cyclone Intensity ◽  
Estimation Scheme

Abstract The advanced Dvorak technique (ADT) is used operationally by tropical cyclone forecast centers worldwide to help estimate the intensity of tropical cyclones (TCs) from operational geostationary meteorological satellites. New enhancements to the objective ADT have been implemented by the algorithm development team to further expand its capabilities and precision. The advancements include the following: 1) finer tuning to aircraft-based TC intensity estimates in an expanded development sample, 2) the incorporation of satellite-based microwave information into the intensity estimation scheme, 3) more sophisticated automated TC center-fixing routines, 4) adjustments to the intensity estimates for subtropical systems and TCs undergoing extratropical transition, and 5) addition of a surface wind radii estimation routine. The goals of these upgrades and others are to provide TC analysts/forecasters with an expanded objective guidance tool to more accurately estimate the intensity of TCs and those storms forming from, or converting into, hybrid/nontropical systems. The 2018 TC season is used to illustrate the performance characteristics of the upgraded ADT.

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