| dc.description.abstract | Air transport is the fastest and safest mode of transport. However, it is the most sensitive to
weather. Adverse weather has a major impact on the safety, efficiency and capacity of
aviation operations. Aircrafts are more vulnerable to severe weather conditions in the vicinity
of aerodromes while taking off and landing which lead to the unavoidable consequences of
reduced operating efficiencies due to delays, diversions and cancellation of flights.
Meteorological forecasts are therefore an important tool for flight planning which has led to
considerable interests in assessing their accuracy, skill and value.
This study examined the influence of adverse weather on aircraft operations at Jomo Kenyatta
InternationalAirport (JlGA) and Wilson Airport. Using aircraft operations data between 2000
and 2009 for JKIA and Wilson, adverse weather was linked with delays and diversions of
aircrafts from both airports. The impacts of delays were measured by the time difference
between the expected time of arrival for an aircraft and the actual time of arrival. Poor
visibility, thunderstorms and wind shear were found to be the major causes of aircraft delays
and diversions. The resultant delays at JKIA and Wilson airports created costs amounting to
over 30,000,000 Kenya shillings. The cost of aircraft diversions at JKIA and Wilson airports
due to adverse weather was estimated to be 1.9 billion Kenya shillings over the ten years of
study.
Forecast verification is essential to monitor forecast quality over time, analyze the different
sources of uncertainty and skill across the entire forecasting process, and compare the quality
of forecasts from different methodologies in order to evaluate forecast skill improvement
from new science and technology. Trend type forecast verification is a driver in forecast
system development since it assists in understanding of predictability. Using four months
trend type forecast for selected hours at JKIA, skill scores for 30 minutes and one and a half
hours were computed from a two way contingency table. The skill scores, on average, were
found to be higher for the thirty minutes forecast as compared to one and half hours forecast. | en |
