Rainfall Trend Analysis using Non-Parametric Test for Raichur Region, Karnataka

Author: Rajashekhar M.*, Rahul Patil and Murali M.

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Abstract

The study of rainfall trends is critically important for a country like India whose food security is dependent on the timely availability of water.The purpose of this study is to identify monthly, seasonal and annual rainfall trends, as well as their magnitude, in the Raichur region in Karnataka. Daily rainfall data from 1981 to 2020 was processed using the Mann-Kendall Test, Modified Mann-Kendall Test and the Sen’s Slope Estimator to determine trend and slope magnitude. The findings of the trend analysis revealed substantial variations in all seasons. Zc readings show a positive trend for ten months and a negative trend for two months. Sen’s slope factor reveals a seven-month positive trend, a one-month negative trend and four months of no change in trend. These statistical tests indicated that the region has undergone minor changes overall.

Keywords

Rainfall trend, Precipitation, Mann-Kendall, Modified Mann-Kendall, Sen’s Slope estimator.

Conclusion

The Zc statistics revealed the trend of the series for 40 years (1981-2020) for individual 12 months from January to December, which are -1.74, 1.15, 0.67, 2.20, 2.11, 2.58, 0.69, 1.43, 1.20, 0.48, -1.12, and 0.20, respectively, in the non-parametric Mann-Kendall test. There is evidence of growing rainfall tendency in the months of February, March, April, May, June, July, August, September, October, and December, whereas Zc value is displaying a negative trend in January and November. Similarly, there is a positive trend in Sen's slope estimator for the months of April, May, June, July, August, September, and October. Only the month of November shows a downward trend. The pattern did not change in the four months of January, February, March, and December. Thus, Zc readings for three months demonstrate a significant condition and non-significant condition for the remaining nine months. The rainfall trend study assisted in understanding the Raichur region's monsoon pattern and so anticip

References

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How to cite this article

Rajashekhar M., Patil, R. and Murali M. (2021). Rainfall Trend Analysis using Non-Parametric Test for Raichur Region, Karnataka. Biological Forum – An International Journal, 13(3a): 248-252.