Identification

Title

Effects of low-level flow orientation and vertical shear on the structure and intensity of tropical cyclones

Abstract

This article explores the simultaneous effect of vertical wind shear (VWS) and low-level mean flow (LMF) on tropical cyclone (TC) structure evolution. The structural evolution of 180 western North Pacific TCs from 2002 to 2014 was measured by a new parameter, the RV ratio, which is defined as the ratio of a TC's radius of 34-kt (17.5 m s(-1)) wind to its maximum wind speed at the ending point of the intensification period. Whereas TCs with RV ratios in the lowest quartile of all 180 samples favored intensification over expansion, and 82% of these TCs experienced rapid intensification, TCs with RV ratios in the topmost quartile favored size expansion over intensification. A novel result of this study is that TC RV ratios were found to correlate with the LMF orientation relative to the deep-layer VWS vector. Specifically, whereas an LMF directed toward the left-of-shear orientation favors TC intensification, a right-of-shear LMF favors TC size expansion. This study further analyzed the TC rainfall asymmetry and asymmetric surface flow using satellite observations. Results show that for a TC affected by an LMF with right-of-shear orientation, the positive surface flux anomaly in the upshear outer region promotes convection in the downshear rainband region. On the other hand, a left-of-shear LMF induces a positive surface flux anomaly in the downshear outer region, thus promoting convection in the upshear inner core. Enhancement of the symmetric inner-core convection favors intensification, whereas enhancement of the downshear rainband favors expansion.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7q24320

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2018-08-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact