| dc.description.abstract | The influence of urbanization on the local climate has been identified in various parts
of the world by a careful study of trends in meteorological parameters over a period of
time. Although these effects may not be immediately discernible, it is necessary to
start investigating what is happening in our cities.
The study examines the long-term urban modification of mean annual conditions of
surface temperature and rainfall in the city of Maseru, Lesotho. This is realized
through studying trends in the minimum and maximum temperatures, rainfall and
number of rain days time series. Data from one urban station (Mejametalana) and
three rural stations (Mafeteng, Moshoeshoe I and Teyateyaneng) was used. The data
comprised minimum and maximum temperatures for the period 1970-2005 and daily
rainfall figures for the period 1922-2005.
The data were tested for homogeneity . using the Short-Cut Bartlett Test, A Variant of
the Standard Normal Homogeneity Test and the Cumulative Mass Curve. Major parts
of the rainfall and temperature time series at both the urban and rural stations were
found to be homogeneous. Some inhomogeneities were observed in the rainfall series
between the late 1920s and early 1930s at both stations, and late 1940s to 1960s at the
rural station.
The sequential version of the Mann-Kendall test was used to investigate any abrupt
changes in the temperature, rainfall and rainy days time series for the urban and rural
stations. Regression analysis was used to delineate the magnitude of trends in the
temperature, rainfall and rainy days time series for the two stations. This was useful in
comparing the trends between the rural stations and the urban station In order to
investigate the urban induced trend.
Results showed that abrupt climatic change in temperatures towards warming
occurred at the urban station than at the rural station. This was observed to be larger in
the minimum temperature series and this began in the early 1990s. No significant
changes in rainfall for the period 1922-2005 were found, except for short time periods
within the series; decreasing trends in rainfall observed during the period between the
mid 1920s and the late 1930s at both the urban and the rural stations. Similarly, no
significant changes in the number of rainy days were observed during the period
1922-2005.
The established significant warming trends in minimum temperature, pose serious
challenges on climate and urban planning of city. In particular the effect of increased
minimum temperature on human physiological comfort, building and urban design,
wind circulation and air pollution. Therefore the findings must be incorporated in the
future planning of the city. | en |
