K. Balathandayutham and C. Mayilswami
Abstract
The subject of trend detection in climate data has received a great deal of attention lately, especially in connection with the anticipated changes in global climate. Precipitation trend analysis, on different scales, has been of great concern during the past century because of the attention given to global climate change by the scientific community. In a study ontemporal trends analysis of rainfall annual and season values were investigated in Parambikulam-Aliyar region. For this purpose, rainfall value collected from 28 rain gauge sites over a 31-year period (19802011) were used and statistically significant rainfall trends in the seasonal and annual time basis were detected using nonparametric Mann-Kendall (MK) tests at the 5% significant level. The results of this study indicated that the rainfall trends for some rain gauge locations were increasing however, for some sites, they showed decreasing trends. The most number of stable trends on an annual time scale occurred at Valparai maximum value of Z value but stable trends was observed in it. On the annual time scale, Parambikulam revealed the highest positive trend (3.7 mm per year). On the other hand, Gomangalam showed the highest decreasing rainfall trend of about 3.465 mm per year. In general, the performances and abilities of the MK tests were consistent at the verified significant level.