Abstract:
An analysis of the shifts and trends of climate patterns with respect to wet
and dry events and rainfall seasonality is vital for the effective planning
and management of water resources in tropical countries such as Sri
Lanka, which have agriculture-based economies. Hence, temporal and
spatial variations of climate extremes and rainfall seasonality in Sri Lanka,
were evaluated in the DL1b Agro-Ecological Zone through the
Standardized Precipitation Index (SPI) and Seasonality Index (SI) utilizing
58 years of daily rainfall data of five selected localities. The Chi-square test
of independence was used to statistically compare the percentage
occurrence of each event recorded during 1961-1988 and 1989-2018. The
dryness of all study areas denoted increments in terms of both severity
and frequency of occurrence in accordance with SPI. However, among the
studied localities of the DL1b agro-ecological zone, only the increment of
dryness in Vavuniya remained statistically significant (Χ2
(df = 4) <9.78;
P=0.04) at 95% level of confidence. Rainfall seasonality of the localities
was characterized with a markedly seasonal climatic condition with a long,
dry season (0.95 – 0.97) with no significant variations and shifts.
Cultivation of low water demanding crops, adjustment of cropping
seasons, use of more efficient water smart irrigation methods,
implementation of agro-forestry systems and employment of smart and
integrated watershed management practices could be recommended as
potential adaptation measures to compensate the impacts of climatic
change.
