Abstract:
Drought is a major and far-reaching global challenge, particularly when it
comes to meteorological droughts, which are extended dry periods caused by
insufficient rainfall. This study aimed to compare the occurrence of
meteorological droughts in dry, wet, and intermediate zones in Sri Lanka,
focusing on Polonnaruwa, Kandy, and Kurunegala districts. The analysis was
based on 30 years of monthly rainfall data (1993-2023) obtained from the
Department of Meteorology of Sri Lanka (Colombo). Standard Precipitation
Index (SPI) was used to analyze the rainfall data and identify periods of
meteorological drought within these districts. The results revealed that
Polonnaruwa experienced drought conditions for 21 out of the past 30 years,
totaling 170 drought months, with most droughts (102 months) occurring
during the Southwest monsoon. In Kurunegala, only the year 2003 was
classified as a moderate drought year, with 56 months identified as moderate
drought periods, mostly during the Northeast monsoon. Interestingly, 15 of
the past 30 years were identified as wet years in the Kurunegala district. The
study also highlighted an increase in meteorological drought events in Kandy
over time, based on SPI findings. From 2007 to 2021 in Polonnaruwa, there
was a decrease in the Normalized Difference Vegetation Index (NDVI) and an
increase in Land Surface Temperature (LST). Both LST and meteorological
drought occurrences are increasing, indicating a positive correlation. Among
the three districts, Polonnaruwa was identified as the most vulnerable to
meteorological droughts. To reduce the impact of drought, the study suggests
measures like water recycling, the adoption of drought-resistant crops, and
increased reforestation efforts.
