Indian Journal of Science and Technology
DOI: 10.17485/ijst/2020/v13i08/149815
Year: 2020, Volume: 13, Issue: 8, Pages: 907 – 920
Original Article
Ashok Singh1,*, Samir Thakur1, Nirab C. Adhikary2
1Department of Applied Sciences, Gauhati University, 781014, Assam, India
2Physical Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon, Garchuk, Guwahati 781035, Assam, India
*Author for correspondence:
Ashok Singh
Department of Applied Sciences, Gauhati University, 781014, Assam, India
E-mail ID: ashok11278@yahoo.com
Objectives: This study explores the rainfall variability and long-term trend in the Brahmaputra plain of northeast region of India. The data analysis is mainly focused on estimating the amount, frequency, and trend of rainfall, using daily recorded data between the year 1950 and 2013.
Methods: Linear Regression analysis was utilized to check the correlation relation between elevation and rainfall. The Mann Kendall test was used to detect a significant trend in rainfall series. Sen’s slope method was used to measure the magnitude of trends in rainfall series. The correlation between time and rainfall was estimated by utilizing Kendall’s tau.
Findings: Data analysis reveals a heaviest-rainfall pockets zone at North Lakhimpur region, wherein annual average rainfall occurs about 3249.57 mm. Another rain shadow zone has detected at Guwahati, wherein annual average rainfall occurs is about 1706.27 mm. A high-low-high gradient in the spatial distribution of seasonal and yearly rainfall has observed from west to east. A similar spatial trend has also observed from south to north along latitudes. The Linear regression analysis reveals a positive relationship between elevation and annual average rainfall. The Mann Kendall test detected a significant rainfall trend on a monthly and seasonal scale whereas, on an annual scale, no significant trend was detected. Rainfall intensity over each station was observed uniform for most of the years. The frequency of light, heavy and very heavy rainfall over the entire Brahmaputra plain region shows a non-significant decreasing trend. Whereas, Dibrugarh and North Lakhimpur experience decreasing trends in the frequency of rainy day and light rainfall and heavy rainfall respectively with a 5% significance level.
Application: The result that comes out from this study shall be useful for the study of soil erosion, water resources management, and agricultural activity and may be useful for adopting flood disaster management policies.
Keywords: Brahmaputra Plain Region, Rainy Day, Mann Kendall Test, Sen’s Slope Method.
Subscribe now for latest articles and news.
