Abstract
The changes in the global rainfall have raised concerns over the present and possible future use of coastal areas in many Asian countries including Sri Lanka. However, no in-depth analysis of rainfall of these coastal lines of Sri Lanka has been performed yet to understand any changes in the pattern in general. This study was carried out to fulfil the above need, especially focusing on rainfall of North-Western and Eastern coastal lines of Sri Lanka. The rainfall data for a period of 30 years (1986–2016) were used in the study and analysis was performed using the tests, Mann Kendall, Sen’s slope estimator, and sequential Mann Kendall. Mann–Kendall’s test indicated positive trend in annual rainfall of most parts of North-Western coastal line but negative monotonic decrease at 4 stations, namely, Chilaw, Horakele, Lunuwila and Palaviya. In the Eastern coastal line, significant positive trend in annual rainfall was observed at 4 stations, namely, Kantale, Batticaloa, Pottuvil and Mylambaveli. The monthly rainfall analysis of North-Western coastal line revealed significant positive trends at Kottukachchiya and Anamaduwa stations in March and December respectively and in the Eastern costal line, positive trends were observed at Kantalae, Mylambaveli and Navatkiri Aru for February. The stations except Anamaduwa in NorthWestern coastal line recorded a significant negative trend in rainfall in the month of May. No station showed a significant positive trend during Southwest Monsoon season. During the Northeast Monsoon season, all the nineteen stations showed an increase in rainfall amounts while two locations in NorthWestern region and six locations in Eastern showed a significant upward trend. With these dynamic rainfall trends, it can be reiterated that it is vital to advocate climate mitigating actions to reduce impacts of changes in rainfall trends.
Highlights
The impact of climate change and climate variability on human life and environment have steered the scientific community to monitor the behaviour of weather and climate variables
The annual rainfall data showed an upward trend for most parts of the North-western and Eastern coastal lines while four stations Chilaw, Horakele, Lunuwila and Palaviyaya in North-western province showed a downward annual trend indicating a monotonic decrease in annual rainfall in these stations
Among these stations Kantale, Palampoddaru, Ampara, Batticaloa, Pottuvil and Mylambaveli of the Eastern coastal line. These observations suggested a drop in rainfall during the Southwest Monsoon period while there was an increase in the rainfall during the northeast monsoon (NEM) season. This overall increase in rainfall during the NEM season agrees with the results reported by Karunathilaka et al (2017) and Naveendrakumar et al (2018)
Summary
The impact of climate change and climate variability on human life and environment have steered the scientific community to monitor the behaviour of weather and climate variables. Temperature and rainfall are very important factors influencing climate variability and extremes. Between these two, changes in rainfall is one of the most important factors, which impact the society and determine the overall impact of climate change (Bhuyan et al, 2018). Changes of the amount, pattern, and intensity of rainfall may lead to extraordinary weather, which is more severe in some parts of the earth (Zamani et al, 2018). The fourth assessment report (AR4) of IPCC (2007) indicated that the low-lying coastal areas in many Asian countries including Sri Lanka are facing challenges associated with changes of the climate
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
