Mona Ghafouri-Azar - PhD student, Department of Civil and Environmental Engineering, Sejong University
Deg-Hyo Bae - Professor, Department of Civil and Environmental Engineering, Sejong University

Trend analysis can enhance our knowledge of the dominant processes in the area and contribute to the analysis of future climate projections. The results of previous studies in South Korea showed that southeast regions of Korea had the highest value of evapotranspiration. Thereby, it is of interest to determine the trend analysis in hydrological variables in this area. In this study, the recent 35 year trends of precipitation, reference evapotranspiration, and aridity index in monthly and annual time scale will be analyzed in Nakdong river basin of South Korea. After removing the significant Lag-1 serial correlationeffect by pre-whitening, non-parametric statistical Mann-Kendall test was used to detect the significant trends in Nakdong River basin. The results showed that the aridity index was mostly affected by precipitation and to a lesser extent by the reference evapotranspiration. The results obtained from this research can be useful for water management practices and cropping systems in this area. Moreover, the methodology of this study can serve as a demonstration of how a time series trend can be analyzed.

Trend analysis, Precipitation, Reference evapotranspiration, Aridity index, Mann-Kendall