 Assessing the state of homogeneity, variability and trends in the rainfall time series from 1969 to 2017 and its significance for groundwater in north-east IndiaParashmoni Borah (),
Suhasini Hazarika () and
Amit Prakash ()
Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards, 2022, vol. 111, issue 1, No 26, 585-617 Abstract: Abstract Rainfall is the key climatic variable, on which water availability, food security and livelihood depend, especially in an agrarian society like the northeast region of India. It is an ecologically sensitive zone, harbouring world’s three biodiversity hotspots and the world’s highest rainfall zone. Therefore, the assessment of variability and trend in the rainfall regime in this region is imperative. The present study focuses on testing the homogeneity status and prevalent trends in the long-term rainfall data at five different locations in North-East India, namely Cherrapunji, Dibrugarh, Guwahati, Kailashahar and Tulihal. The impact of rainfall variability on groundwater level was further investigated. The estimation of precipitation concentration index and standard precipitation anomaly was also carried out to investigate the intra-annual variability and drought conditions in this region. The results indicate the homogeneous nature of rainfall time series at 99% significance level at all the sites with low coefficient of variance (CV, %) at Dibrugarh in monsoon and annual rainfall series. The precipitation concentration index values show high intra-annual variability in the rainfall data. Decadal and annual standard precipitation anomaly values indicate the presence of extreme and severe drought conditions in the last two decades. The trend analysis results display the presence of significant negative trends in monsoonal and annual rainfall at Dibrugarh. During pre-monsoon season, all the sites exhibiting positive drift with only Guwahati and Tulihal have significant trends (at 90% significance level). Monthly rainfall trend analysis results revealed strong and significant (95%) negative trends during peak monsoon months of July at Dibrugarh and Guwahati and with 85% significance level at Cherrapunji (which was the world’s highest rainfall zone in recent past). The impact assessment results indicate a direct association between rainfall and groundwater at lag2, i.e., the impact of any change in the rainfall amount on groundwater in a given area may be evident after two seasons. The results revealed an enhancement of 1.0 ± 0.1, 1.1 ± 0.2, 0.9 ± 0.2 mm in the groundwater level for each mm increase in the rainfall at DBR, GHY and KSH, respectively. At CHR, the relation was evident only after 10 seasons because of excessive rainfall and runoff. The results had significant bearing for the policy makers and farming community in the region for better planning of crop cultivation in order to adapt to the changing climate in this region. Keywords: Precipitation concentration index; Standard precipitation anomaly; Homogeneity test; Rainfall trend; Groundwater; North-east India (search for similar items in EconPapers) Downloads: (external link) Related works: Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text Persistent link: https://EconPapers.repec.org/RePEc:spr:nathaz:v:111:y:2022:i:1:d:10.1007_s11069-021-05068-y Ordering information: This journal article can be ordered from DOI: 10.1007/s11069-021-05068-y Access Statistics for this article Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards is currently edited by Thomas Glade, Tad S. Murty and Vladimír Schenk More articles in Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards from Springer, International Society for the Prevention and Mitigation of Natural Hazards |
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