# Homogeneity and Trend Analysis of Climatic Variables in Cap-Bon Region of Tunisia
## 4 Conclusions  
The assessment of temporal variability in different climatic variables due to possible climate change or human intervention is important for water resources planning and management at the regional and local scales. In this study, change point detection and trend analysis in the monthly, seasonal and annual maximum and minimum air temperature and precipitation time series in the Nabeul region have been performed. The Pettitt test and the SNHT were used for change point detection. Mann-Kendall and autocorrelated Mann-Kendall tests were adopted for trend analysis. The change point results indicate that the maximum air temperature showed significant breaks in the annual and most of the seasonal and monthly time series. Meanwhile, no significant change point has been recorded in the winter season and in its corresponding months. These break dates have occurred simultaneously with the rapid development period in the region. The development of agricultural, industrial and tourist activities have increased greenhouse gas and air pollution emissions. The application of Pettitt test to minimum air temperature \begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Before Break Point If Any**} & \multicolumn{4}{c}{**After Break Point If Any**} \\ \cline{2-10}  & **MK** & **mMK** & **Sen** & **TFWMK** & **Sen** & **MK** & **mMK** & **Sm** & **TFWMK** & **Sen** \\  & \(p\)**-Value** & \(p\)**-Value** & & \(p\)**-Value** & & \(p\)**-Value** & \(p\)**-Value** & **Sen** & **TFWMK** & **Sen** \\ \hline Annual & 0.161 & 0.161 & \(-3.754\) & 0.327 & \(-2.505\) & & & & \\ Winter & 0.093 & 0.093 & \(-1.674\) & 0.191 & \(-1.516\) & & & & \\ Spring & 0.236 & 0.236 & 0.440 & 0.327 & 0.733 & & & & \\ Summer & 0.681 & 0.787 & 0.044 & 0.960 & 0.025 & & & & \\ Autumn & 0.371 & 0.413 & \(-1.238\) & 0.633 & \(-0.571\) & & & & \\ January & 0.157 & 0.102 & \(-0.656\) & 0.280 & \(-0.418\) & & & & \\ February & 0.468 & 0.258 & 0.217 & 0.393 & 0.315 & & & & \\ March & 0.865 & 0.865 & \(-0.073\) & 0.940 & 0.070 & & & & \\ April & 0.961 & 0.961 & \(-0.021\) & 1.000 & \(-0.006\) & & & & \\ May & 0.553 & 0.616 & \(-0.116\) & 0.687 & \(-0.066\) & & & & \\ June & 0.809 & 0.809 & \(-0.006\) & 0.513 & \(-0.026\) & & & & \\ July & 0.815 & 0.815 & 0.000 & 0.279 & \(-0.034\) & & & & \\ August & 0.707 & 0.772 & 0.004 & 0.597 & 0.029 & & & & \\ September & 0.327 & 0.255 & 0.427 & 0.269 & 0.546 & & & & \\ October & 0.654 & 0.654 & \(-0.173\) & 0.980 & 0.002 & & & & \\ November & 0.061 & 0.061 & \(-0.850\) & 0.078 & \(-0.614\) & & & & \\ December & 0.290 & 0.290 & 1.35 & 0.154 & 1.39 & 1.000 & 1.000 & 0.000 & 0.940 & \(-0.034\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of the statistical tests for the precipitation. data indicated the existence of significant breaks in both March and April. Regarding the precipitation time series, a significant abrupt change was recorded in December. Mann-Kendall results show a significant warming trend in annual Tmax with magnitudes equal to 0.065 and 0.045 \({}^{\circ}\)C/year, respectively, before and after the breakpoint. Nevertheless, non-significant tendencies were observed in the annual Tmin and P time series. On the monthly scale, Tmax exhibited a significant upward trend in June and August, before the observed breakpoints, with Sen's slope values equal to 0.065 and 0.045 \({}^{\circ}\)C/year, respectively. Mann-Kendall trend analysis results evidenced a warming trend in the annual Tmax, which is probably due to the fast development and human interventions in the study region. Despite the existence of a significant increasing trend in the whole datasets of most of the seasonal and monthly Tmax series, no significant trend could be recognized when dividing the time series at the significant breakpoint. Except for June and August, significant upward trends were detected, before the observed breakpoints, in the Tmax time series with Sen's slope values equal to 0.065 and 0.045 \({}^{\circ}\)C/year, respectively.