East Asia and Western Pacific METEOROLOGY AND CLIMATE

261
THE IMPACT OF URBANIZATION ON CLIMATE
IN HONG KONG AND ITS IMPLICATIONS FOR
HUMAN ENERGY EXCHANGES
by
William J. Kyle
Department of Geography & Geology
University of Hong Kong
Hong Kong
ABSTRACT
The impact of urbanization on long-term climatic changes
as evidenced by trends in temperature and wind speed
measured at the Royal Observatory, Hong Kong is examined.
Evidence shows a long-term warming trend concurrent with
increasing urbanization. Further investigation
attributes this trend to both horizontal expansion in
the built-up areas around the Observatory as well as
vertical expansion in more recent years. A definite
declining trend in post-war surface wind speed is also
evident and is linked to this latter phase of
urbanization. These two trends are examined within the
context of the commonly hypothesized causal factors for
the development of an urban canopy layer heat island.
The implications for human energy exchanges of this
warming trend are examined and an evaluation of the
likely effect on human thermal comfort is presented.
INTRODUCTION
It has been stated that the most obvious climatic manifestation
of urbanization is the trend towards higher temperatures, thi's trend
depending on the prevailing synoptic conditions (Landsberg, 6)). Urban
climates are really differentiated topoclimates and as such depend on
variation of radiative fluxes and turbulent exchanges, the contrasts of
which are greatest in clear, calm conditions and least in cloudy, windy
weather.