Sri Lanka is well known as an agricultural country from an ancient time. The primary source of water for agricultural production for most of the world is rainfall. Three main characteristics of rainfall are its amount, frequency and intensity, the values of which vary from place to place, day to day, month to month and also year to year. Precise knowledge of these three main characteristics is essential for planning its full utilization. Most rain water is used in agriculture for crop production. Therefore, the rainfall trend analysis is very important to decide the adequacy of rainfall amount for crop irrigation etc.
Climate change impacts on agriculture invariably impacts the country’s economy. Rainfall received in any region can vary with …show more content…
The Mann-Kendall statistic, the Spearman statistic and the least-square regression method were chosen to detect trend in a time series for the research work. The Mann-Kendall rank statistic is a non-parametric test, which can be used to test for the existence of a linear trend while the Spearman’s test confirms the result. In order to test the existence of a linear trend, the data set was divided into years) and short-range study (36 to 50 years) and analysed. A long-term increasing trend at the 95% confidence level was observed at Colombo with a rate of 3.15 mm/year. Decreasing long-term trends were found at two locations, Nuwara Eliya at a rate of 4.87 mm/year and Kandy at a rate of 2.88 mm/year. However, more recent data records (1949 onwards), revealed a decreasing trend in 13 of the 15 stations. In general, the downward trends in recent decades are steeper than the long term variations. For the recent data records, the largest downward trend of 11.16 mm/year was observed at …show more content…
Spatio-temporal trends in the rainfall received during the four rainy seasons – i.e., the Southwest monsoon, the first inter-monsoon, the Northeast monsoon and the second inter-monsoon during the period 1961-2002 (minimum 30-year period) were analysed. The study found that the number of rainy days has decreased at all the meteorological stations except for the Nuwara Eliya station. It also finds that the 2000 mm isohyet – demarcating the wet zone of the country - has
Climate change impacts on agriculture invariably impacts the country’s economy. Rainfall received in any region can vary with …show more content…
The Mann-Kendall statistic, the Spearman statistic and the least-square regression method were chosen to detect trend in a time series for the research work. The Mann-Kendall rank statistic is a non-parametric test, which can be used to test for the existence of a linear trend while the Spearman’s test confirms the result. In order to test the existence of a linear trend, the data set was divided into years) and short-range study (36 to 50 years) and analysed. A long-term increasing trend at the 95% confidence level was observed at Colombo with a rate of 3.15 mm/year. Decreasing long-term trends were found at two locations, Nuwara Eliya at a rate of 4.87 mm/year and Kandy at a rate of 2.88 mm/year. However, more recent data records (1949 onwards), revealed a decreasing trend in 13 of the 15 stations. In general, the downward trends in recent decades are steeper than the long term variations. For the recent data records, the largest downward trend of 11.16 mm/year was observed at …show more content…
Spatio-temporal trends in the rainfall received during the four rainy seasons – i.e., the Southwest monsoon, the first inter-monsoon, the Northeast monsoon and the second inter-monsoon during the period 1961-2002 (minimum 30-year period) were analysed. The study found that the number of rainy days has decreased at all the meteorological stations except for the Nuwara Eliya station. It also finds that the 2000 mm isohyet – demarcating the wet zone of the country - has