Author(s)

Franck Zokou Yao^1,2*, Emmanuel Reynard², Ismaïla Ouattara¹, Yao Alexis N’go¹, Jean-Michel Fallot², Issiaka Savané¹

¹Faculty of Sciences and Environmental Management, University Nangui Abrogoua, Abidjan, Côte d’Ivoire.
²Institute of Geography and Sustainability, University of Lausanne, Lausanne, Switzerland.

The population of northern Côte d’Ivoire, especially in the white Bandama watershed, lives for majority in rural areas and depends on farming, which is mainly linked to climate variability. This study evaluates the trends within watershed’s hydro-climatic variables and their level of significance over the period 1950-2000. The methodological approach consists in applying successively standardized indexes to detect trends and breaks in hydro-climatic long-term data. The Mann-Kendall statistical test lets us know the trends significance and the Kendall-Theil Robust Line test reveals their magnitude. The Student’s t test underlines break years. Results show that although rainfall has decreased, this decline is not statistically significant. However, temperature and potential evapotranspiration have strongly rised and discharge was submitted to high decline. These changes in hydrometeorological variables appeared from 1970 to 1980. This study is different from others conducted on climate variability in the northern Côte d’Ivoire by the methodological statistical framework implemented and the understanding of significance level of climate trends. Until now, authors used the standardized index to detect trends in hydro-climatic parameters. For this work, we added the Mann-Kendall statistical test to assess the significance level of these trends at α = 5% and 10%. Then, the Kendall-Theil statistical test was used to highlight the trends magnitude and the student’s t test to know the break years.

Hydro-Climatic Trend, Statistical Tests, White Bandama Watershed

Yao, F. , Reynard, E. , Ouattara, I. , N’go, Y. , Fallot, J. and Savané, I. (2018) A New Statistical Approach to Assess Climate Variability in the White Bandama Watershed, Northern Côte d’Ivoire. Atmospheric and Climate Sciences, 8, 410-430. doi: 10.4236/acs.2018.84027.