THESIS
2017
133 pages : illustrations (some color) ; 30 cm
Abstract
Pearl River Delta (PRD) region has experienced fast economic development
since 1980s and becomes one of the world’s largest industrial zones and metropolitan
areas. However severe air pollution problems such as high concentration of ozone and
particulate matter arise with the rapid urbanization and industrial development.
According to previous studies, sea breeze circulation can contribute to pollutant
transportation and convective initiation, so it is meaningful to study the dynamical
structure of sea-breeze circulations in PRD region. Many researchers have focused on
the effects of environmental factors, such as topography, urbanization and background
wind, on sea breeze, but most of them only focused on case studies and did not quantify
the characteristics of sea breeze circ...[
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Pearl River Delta (PRD) region has experienced fast economic development
since 1980s and becomes one of the world’s largest industrial zones and metropolitan
areas. However severe air pollution problems such as high concentration of ozone and
particulate matter arise with the rapid urbanization and industrial development.
According to previous studies, sea breeze circulation can contribute to pollutant
transportation and convective initiation, so it is meaningful to study the dynamical
structure of sea-breeze circulations in PRD region. Many researchers have focused on
the effects of environmental factors, such as topography, urbanization and background
wind, on sea breeze, but most of them only focused on case studies and did not quantify
the characteristics of sea breeze circulations (including start time, end time, strength,
height, occurrence frequency and inland penetrating distance).
In this research a new method to quantify the characteristics of these sea breeze
cases has been identified. The coastal lines in PRD region are simplified into one
heptagon which almost covers the Pearl River Estuary and the positive diurnal signals of
wind flux over the heptagon are taken as sea breeze cases. Similarly, the complex coasts
along Guangdong province are enclosed by two rectangles and the positive diurnal
signals of averaged inshore divergent wind in these two rectangles are considered as sea
breeze cases. This method has been applied to analyze sea-breeze events in 2012 and results indicate that this method can quantify the characteristics of sea breeze
circulations well.
Averaged prognostic variables like circulation, solenoid term and frontogenesis
function can be evaluated to illustrate the dynamical process of sea-breeze circulation.
Results imply that sea-breeze driven by thermal difference between land and sea can
also diminish this temperature difference with vertical motion, in return. During this
process, divergence and deformation also has some impacts on sea-breeze circulation.
This research can also evaluate the implication of urbanization on sea breeze circulation
quantitatively with frontogenesis function. It is expected that this research will
demonstrate the mechanism in which sea breeze circulation can be modulated by
urbanization.
Keywords: Sea-breeze Circulation, Urbanization, PRD Region, Solenoid term,
Frontogenesis function
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