Land-based convection effects on formation of tropical cyclone Mekkhala (2008)
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Authors
Park, Myung-Sook
Lee, Myong-In
Kim, Dongmin
Bell, Michael M.
Cha, Dong-Hyun
Elsberry, Russell L.
Subjects
Tropical cyclones
Mesoscale systems
Numerical analysis/modeling
Mesoscale systems
Numerical analysis/modeling
Advisors
Date of Issue
2017-04
Date
April 2017
Publisher
American Metorological Society
Language
Abstract
The effects of land-based convection on the formation of Tropical Storm Mekkhala (2008) off the west coast
of the Philippines are investigated using the Weather Research and Forecasting Model with 4-km horizontal
grid spacing. Five simulations with Thompson microphysics are utilized to select the control-land experiment
that reasonably replicates the observed sea level pressure evolution. To demonstrate the contribution of the
land-based convection, sensitivity experiments are performed by changing the land of the northern Philippines
to water, and all five of these no-land experiments fail to develop Mekkhala.
The Mekkhala tropical depression develops when an intense, well-organized land-based mesoscale convective
system moves offshore from Luzon and interacts with an oceanic mesoscale system embedded in a
strong monsoon westerly flow. Because of this interaction, a midtropospheric mesoscale convective vortex
(MCV) organizes offshore from Luzon, where monsoon convection continues to contribute to low-level
vorticity enhancement below the midlevel vortex center. In the no-land experiments, widespread oceanic
convection induces a weaker midlevel vortex farther south in a strong vertical wind shear zone and subsequently
farther east in a weaker monsoon vortex region. Thus, the monsoon convection–induced low-level
vorticity remained separate from the midtropospheric MCV, which finally resulted in a failure of the low-level
spinup. This study suggests that land-based convection can play an advantageous role in TC formation by
influencing the intensity and the placement of the incipient midtropospheric MCV to be more favorable for
TC low-level circulation development.
Type
Conference Paper
Description
The article of record as published may be found at http://dx.doi.org/10.1175/MWR-D-16-0167.1
Series/Report No
Department
Meteorology
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Korea Meteorological Administration Research and Development Program
National Science Foundation CAREER Award
Office of Naval Research Young Investigator Program Award
U.S. Office of Naval Research
National Science Foundation CAREER Award
Office of Naval Research Young Investigator Program Award
U.S. Office of Naval Research
Funder
AGS-1349881
N000141512601
N141410275
N000141512601
N141410275
Format
23 p.
Citation
Park, Myung-Sook, et all, "Land-based convection effects on formation of tropical cyclone Mekkhala (2008)." American Meteorological Society, April 2017
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.