Using self-organizing maps to understand the effects of synoptic configurations on Western North Pacific tropical cyclones

Zhou, Fangyi

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https://hdl.handle.net/2142/116113 Copy

Description

Title

Using self-organizing maps to understand the effects of synoptic configurations on Western North Pacific tropical cyclones

Author(s)

Zhou, Fangyi

Issue Date

2022-07-20

Director of Research (if dissertation) or Advisor (if thesis)

Nesbitt, Stephen

Committee Member(s)

• Wang, Zhuo
• Hence, Deanna

Department of Study

Atmospheric Sciences

Discipline

Atmospheric Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Tropical Cyclone
• Western North Pacific
• Environment
• Self-Organizing Maps

Abstract

The vertical wind shear (VWS) within the tropical cyclone (TC) environment is a crucial factor affecting the track and intensity of the TCs. Classic theories in the 1950s proposed that weaker vertical wind shear favors the development of TCs. Several studies have been long investigating the physical linkages between the VWS and TCs. However, TC vertical wind shear is essentially a part of the larger environment, subject to the background fields and synoptic configurations. Research about how the large-scale environmental fields adjust and influence the VWS and TC properties is limited and incomplete. In this study, we perform a cluster analysis to understand how the synoptic configurations affect the pattern of VWS, and what influence they have on TC activities in the Western North Pacific. A machine learning method, “self-organizing maps” (SOMs) is applied in this study to identify and discriminate the meteorological patterns in TC environment. A sample of 309 storms during 2010 - 2019 were examined, and several factors were used for SOM training. By inspecting the characteristics of other variables corresponding to these patterns, this thesis encompasses the discussion of TC time distribution, evolvement, environmental VWS, and large-scale environment, where evident correlation between these variables is found and revealed. The development of TCs is demonstrated in an evolutional manner, where the presence and state of the major weather systems in this area such as Western North Pacific Subtropical High (WNPSH), South Asian High (SAH), and monsoon gyre are closely related to the separate stages of TCs and invoke TC variations.

Graduation Semester

2022-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Fangyi Zhou

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