George Lukoye Makokha

Determination of seasonal rainfall variability, onset and cessation in semi-arid Tharaka district, Kenya

The study quantified rainfall variability for March–May (MAM) and October–December (OND) seasons in Tharaka district, Kenya. The parameters analysed were inter-annual variability of seasonal rainfall, onset and cessation using daily rainfall data in three agro-ecological zones’ stations. Percentage mean cumulative method was used to determine onset and cessation, and seasonal variability was estimated using rainfall variability indices. Although both seasons are highly variable, OND has been persistently below mean over time while MAM shows high within-season variability. Despite the near uniformity in the mean onset and cessation dates, the former is highly variable on an inter-annual scale. The two rainfall seasons are inherently dissimilar and therefore require specific cropping in agro-ecological zone LM4 and LM4-5. It is possible that farmers in IL5 are missing an opportunity by under-utilising MAM rainfall. The results should be incorporated in implications of climate variability and vulnerability assessment in semi-arid Tharaka district.

Trends in Mean Annual Minimum and Maximum Near Surface Temperature in Nairobi City, Kenya

This paper examines the long-term urban modification of mean annual conditions of near surface temperature in Nairobi City. Data from four weather stations situated in Nairobi were collected from the Kenya Meteorological Department for the period from 1966 to 1999 inclusive. The data included mean annual maximum and minimum temperatures, and was first subjected to homogeneity test before analysis. Both linear regression and Mann-Kendall rank test were used to discern the mean annual trends. Results show that the change of temperature over the thirty-four years study period is higher for minimum temperature than maximum temperature. The warming trends began earlier and are more significant at the urban stations than is the case at the sub-urban stations, an indication of the spread of urbanisation from the built-up Central Business District (CBD) to the suburbs. The established significant warming trends in minimum temperature, which are likely to reach higher proportions in future, pose serious challenges on climate and urban planning of the city. In particular the effect of increased minimum temperature on human physiological comfort, building and urban design, wind circulation and air pollution needs to be incorporated in future urban planning programmes of the city.

Temperature Cooling and Warming Rates in Three Different Built Environments within Nairobi City, Kenya

Urban canyon, urban park, and suburban surface air temperature data for hot-wet, hot-dry, cool-dry, and warm-wet periods in Nairobi city were analyzed to detect differences in the cooling and warming rates. Measurement of temperature for thirty continuous days was done at each of the three sites for each of the above periods. The cooling and warming rates were computed on an hourly basis beginning at 6.00 P.M., the approximate time of sunset. The results of the study showed that the largest cooling and warming rates were generally experienced during the hot-dry period while the lowest during the cool-dry period. Cooling and warming rates were also found to be the highest at the suburban site and the lowest at the urban canyon site. The differences in the conditions of the built environment at the three sites could explain the cause of the differential cooling and warming rates. The study recommends proper planning of the built environment to ameliorate the problem of excessive nocturnal heat loads within the built environment.

Variations of the effective temperature index (ET) in Kenya

Using the Effective Temperature Index (ET) as a measure of climatic comfort conditions in Kenya, this study analyses its spatial, seasonal and diurnal variations. This index is computed using data collected from 57 weather stations spread throughout the country. Isarithmic mapping technique and the conditioning square method are used in this analysis. The results indicate that there exists in Kenya marked spatial, seasonal and diurnal variations of climatic comfort conditions. A classification of the country using this index and the Terjung (1968) system of climatic classification yields six climatic comfort zones. This type of physio-climatic studies has significant implications for Kenya in aspects such as building, clothing, recreation and sporting.

Challenges Affecting Adoption of E-Learning in Public Universities in Kenya.

Public universities in Kenya are, today, turning to the use of e-learning in an attempt to cope with the rapidly increasing demand for university education. This research was conducted between February 2012 and February 2014 to determine the challenges affecting the adoption of e-learning in these institutions of higher learning. Data were collected using questionnaires administered to 420 lecturers and 210 students, and analysed through the use of simple descriptive statistics. Lecturers ranked heavy workloads the most serious challenge affecting the adoption of e-learning, followed by: insufficient Internet connectivity, denial of copyrights for their developed e-learning modules, limited information and communication technology (ICT) skills, lack of incentives, shortage of computers/laptops, inadequate computer laboratories, and insufficient time for online interaction. Students, on the other hand, ranked insufficient Internet connectivity the number-one challenge, followed by: lack of computers/laptops, inadequate computer laboratories, limited ICT skills, and insufficient time for online interaction. The paper concludes that as a result of these challenges, the adoption of e-learning is slow and still at its infancy stage in public universities in Kenya. It recommends that universities should invest heavily in the improvement of e-learning infrastructure, e-learning content development, capacity building, attitude change, and enhancement of e-learning awareness.