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Why Do the Maximum Intensities in Modeled Tropical Cyclones Vary Under the Same Environmental Conditions?
Author(s) -
Tao Dandan,
Bell Michael,
Rotunno Richard,
Leeuwen Peter Jan
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl085980
Subject(s) - tropical cyclone , mixing (physics) , radius , turbulence , physics , atmospheric sciences , storm , environmental science , meteorology , mechanics , computer security , quantum mechanics , computer science
In this study w e explored why the different initial tropical cyclone structures can result in different steady‐state maximum intensities in model simulations with the same environmental conditions. We discovered a linear relationsh ip between the radius of maximum wind ( r m ) and the absolute angular momentum that passes through r m ( M m ) in the model simulated steady‐state tropical cyclones that r m = aM m + b . This nonnegligible intercept b is found to be the key to making a steady‐state storm with a larger M m more intense. The sensitivity experiments show that this nonzero b results mainly from horizontal turbulent mixing and decreases with decreased horizontal mixing. Using this linear relationship from the simulations, it is also found that the degree of supergradient wind is a function of M m as well as the turbulent mixing length such that both a larger M m and/or a reduced turbulent mixing length result in larger supergradient winds.