National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
The present study intended to determine potential trends in monthly, seasonal and annual rainfall in the Brahmaputra valley of Assam during 1986-2015, based on observed daily rainfall data from 10 locations. The magnitude of the trends was estimated using Theil-Sen’s slope method, while statistical significance of the trends was tested using Mann-Kendall rank statistics. Analysis revealed that mean annual rainfall varied from 1653.5 mm in Golaghat to 3676.9 mm in Gossaigaon, with variability in order of 13-32 per cent at different locations. Annual rainfall was found to decrease in all the 10 stations, with a significant decrease in Golaghat, Dhubri, Kamrup and Tezpur. On seasonal basis, pre-monsoon rainfall indicated increasing trends at Jorhat, Golaghat, Lilabari, Mohanbari, Beki and Tezpur during the study period. Conversely, rainfall during the monsoon season exhibited significant decreasing trends at Beki, Dhubri, Shillongoni and Tezpur, due to the corresponding significant decrease in July and September rainfall in the locations. Similar decreasing rainfall trends were also observed during post-monsoon season in all the stations. During winter, due to significant decrease in February rainfall, all the stations showed decreasing rainfall trends, with statistically significant values for Golaghat, Lilabari, Mohanbari, Kamrup, Shillongoni and Tezpur, as per Mann-Kendall rank statistics.
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