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The influence of urban morphology on sensible heat flux and convective rainfall distributions over Greater Manchester

Carraca, MDGD

Authors

MDGD Carraca



Contributors

C Collier
Supervisor

Abstract

Human activities, and alterations of the nature and morphology of the land
surface, perturb the land surface- atmosphere balances of energy, mass and
momentum. These changes lead to modifications of the atmospheric boundary layer
which affect weather processes. Specifically, urban areas have been documented to
change temperature distributions, wind patterns and air quality. They can also impact
the development of clouds and precipitation in and around cities.
Among the causes ascribed to the modification of convective precipitation
induced by urbanisation, most studies suggest that the atmospheric destabilisation
associated with the heat island and surface roughness is the most significant, more so
than microphysical or moisture enhancement. However the relative importance of
these mechanisms remains unclear.
The present work reports an investigation of the effects of urban surface
heterogeneity on the distribution of sensible heat flux and its impact on convective
precipitation, in Greater Manchester. A simple numerical scheme is formulated to
derive fields of surface sensible heat flux for a range of wind and temperature values
over the urban area. This involves the derivation and mapping of urban surface
morphologic characteristics such as the height of buildings and the frontal area index.
Comparisons are made with previously published morphologies derived for other
urban areas. The sensible heat flux values from the numerical procedure are compared
to direct independent measurements for a number of days. The sensible heat flux field
and the rainfall field measured using a C-band radar are compared. The possible
influences of the urban morphology on the rainfall distribution, and the eventual
initiation of convective cells by the sensible heat flux input generated over buildings in
Manchester city centre, are discussed.

Citation

Carraca, M. The influence of urban morphology on sensible heat flux and convective rainfall distributions over Greater Manchester. (Thesis). University of Salford

Thesis Type Thesis
Deposit Date Aug 16, 2021
Additional Information Funders : Fundaqao Eugenia de Almeida
Award Date Sep 1, 2008

This file is under embargo due to copyright reasons.

Contact Library-ThesesRequest@salford.ac.uk to request a copy for personal use.





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