MANN-KENDALL AND SEN'S SLOPE ESTIMATOR STATISTICAL TESTS FOR ANALYZING CHANGES IN METEOROLOGICAL VARIABLES IN KWALE COUNTY, KENYA

  • Kevin Morang'a Department of Environmental Science and Education, Kenyatta University, Kenya
  • Dr. Ezekiel Ndun Department of Environmental Science and Education, Kenyatta University, Kenya
  • Dr. Dan Adino Department of Department of Anthropology and Gender Studies, University of Nairobi, Kenya
Keywords: climate change, precipitation trends, temperature trends, Sen's slope, Mann-Kendall

Abstract

Temperature and Precipitation variables were examined for 40 years in the four sub-counties of Kwale County in Kenya between 1980 and 2022. The statistical significance of the meteorological data was utilized to evaluate whether a positive or negative trend existed using the non-parametric Sen's and Mann-Kendall approaches. Annual temperature trends are positive and statistically significant for Kinango (ZS=0.692 , Qmed=0.049, p<0.001); Lunga Lunga (ZS=0.677 , Qmed=0.040, p<0.001); Msambweni (ZS=0.610 , Qmed=0.042, p<0.001) and; Matuga (ZS=0.641 , Qmed=0.043, p<0.001). However, the annual precipitation trends not statistically significant for Kinango (ZS=0.026, Qmed=0.003, p>0.005); Lunga Lunga (ZS=0.210 , Qmed=0.017, p>0.001); Msambweni (ZS=-0.077, Qmed=-0.011, p>0.001) and; Matuga (ZS=0.146, Qmed=0.011, p>0.001). Precipitation has not significantly changed in Kinango, Msambweni, Lunga Lunga, and Matuga. It is only in Lunga Lunga during June that precipitation changed significantly and in November for Lunga Lunga. Msambweni showed a slight positive change. In Matuga in november, there is a substantial positive upsurge in precipitation. From the study, climate change is occurring in Kwale County, Kenya.

References

[1] ElNesr, M.N., Abu-Zreig, M.M., Alazba, A.A., 2010. Temperature trends and distribution in the Arabian Peninsula. American Journal of Environmental Sciences 6, 191–203.
[2] Jiang, Y., Luo, Y., Zhao, Z., Tao, S., 2010. Changes in wind speed over China during 1956–2004. Theoretical and Applied Climatology 99 (3–4), 421–430.
[3] Karaburun, A., Demirci, A., Kara, F., 2011. Analysis of spatially distributed annual, seasonal and monthly temperatures in Istanbul from 1975 to 2006. World Applied Sciences Journal 12 (10), 1662–1675.
[4] Kendall, M.G., 1975. Rank Correlation Methods. Griffin, London, UK.
[5] Kendall, M.G., Stuart, A., 1968. The Advanced Theory of Statistics: Design and Analysis, and Time-series, vol. 3. Charles Griffin & Company Limited, London.
[6] Modarres, R., Silva, V.P.R., 2007. Rainfall trends in arid and semi-arid regions of Iran. Journal of Arid Environments 70, 344–355.
[7] Philipona, R., Durr, B., Ohmura, A., Ruckstuhl, C., 2005. Anthropogenic greenhouse forcing and strong water vapor feedback increase temperature in Europe. Geophysical Research Letters 32, L19809. http://dx.doi.org/10.1029/2005GL023624.
[8] Rupa, T. R., Rejani, R., & Bhat, M. G. (2013). Impact of climate change on cashew and adaptation strategies. In Climate-Resilient Horticulture: Adaptation and Mitigation Strategies (pp. 189-198). Springer, India.
[9] Singh, P., Kumar, V., Thomas, T., Arora, M., 2008. Changes in rainfall and relative humidity in river basins in northwest and central India. Hydrological Processes 22 (16), 2982–2992.
[10] Smadi, M. (2006) Observed Abrupt Changes in Minimum and Maximum Temperatures in Jordan in the 20th Century. American Journal of Environmental Sciences, 2, 114-120.
[11] Tabari, H., Hosseinzadeh Talaee, P., 2011a. Analysis of trends in temperature data in arid and semi-arid regions of Iran. Global and Planetary Change 79 (1–2), 1–10.
[12] Tao, H., Gemmer, M., Bai, Y., Su, B., Mao, W., 2011. Trends of streamflow in the Tarim River Basin during the past 50 years: human impact or climate change? Journal of Hydrology 400 (1–2), 1–9.
[13] Trajkovic, S., Kolakovic, S., 2009. Wind-adjusted Turc equation for estimating reference evapotranspiration at humid European locations. Hydrology Research 40 (1), 45–52.
[14] Trenberth, K.E., Fasullo, J., Smith, L., 2005. Trends and variability in column-integrated atmospheric water vapor. Climate Dynamics 24, 741–758.
[15] Vincent, L.A., Wijngaarden, W.A., Hopkinson, R., 2008. Surface temperature and humidity trends in Canada for 1953–2005. Journal of Climate 20 (20), 5100–5113.
[16] Willett, K.M., Gillett, N.P., Jones, P.D., Thorne, P.W., 2007. Attribution of observed surface humidity changes to human influence. Nature 449 (7163), 710–713.
[17] Woolf, D., Amonette, J. E., Street-Perrott, F. A., Lehmann, J., & Joseph, S. (2010). Sustainable biochar to mitigate global climate change. Nature communications, 1(1), 1-9.
[18] Xu, Z., Liu, Z., Fu, G., Chen, Y., 2010. Trends of major hydroclimatic variables in the Tarim River Basin during the past 50 years. Journal of Arid Environments 74 (2), 256–267.
[19] Yunling, H., Yiping, Z., 2005. Climate change from 1960 to 2000 in the Lancang River Valley, China. Mountain Research and Development 25 (4), 341–348.
Published
2022-08-22
How to Cite
Morang’a, K., Ndun, D. E., & Adino, D. D. (2022). MANN-KENDALL AND SEN’S SLOPE ESTIMATOR STATISTICAL TESTS FOR ANALYZING CHANGES IN METEOROLOGICAL VARIABLES IN KWALE COUNTY, KENYA. IJRDO Journal of Forestry, Wild Life and Environment , 8(8), 1-12. Retrieved from http://13.234.104.160/index.php/few/article/view/5270
Issue
Vol. 8 No. 8 (2022): Journal of Forestry, Wild Life and Environment
Section
Articles