Abstract:
Increaseof the global temperature particularly after the industrial era, has a nmnber of
impactson climate leading to changes globally and locally. Lightning activity at any
particular place has been affected by the global warming and the climate change
during the past few decades.
The objectiveof this study was to determine the variability of thunder activity in Sri
Lanka as a result of the climate change. Time series analysis was carried out to
identifythe trend in thunder activity and temperature over the period from 1961-2002.
Correlationanalysis was done by using STATISTICA to establish the relationship
betweenthunder activityand temperature.
Data from six stations, Colombo, Galle, Kandy, Hambanthota, Anmadhapura and
Katunayeka,were used in the investigation. Trend analysis revealed that there has
been an up ward trend in the occmrence of thunder activity in all stations except
Hambanthota and Katunayaka. The highest trend of thunder activity has been
recordedas +0.78 thunder day/year at Colombo and the lowest rate of -0.04 thunder
day/year at Hambanthota.
Trend analysis indicated that the mean temperature has been increasing at all the
stations.The highest mean temperature trend has been recorded as +o.O3loC/year at
Anuradhapuraand the lowest rate of increase of +0.016oC/yearhave been recorded at
Katunayaka.
The trend of the thunder activity and mean temperature of the first half period (1961-
1980) is larger than the second half period (1981-2002) at Colombo, Kandy and
AnuradhapuralInother words rate of increment is decreasing at these stations.
