Development of a new integrated method for generation of IDF curves based on three scenarios of climatic changes

Abstract

Climate change can change the Intensity-Duration-Frequency (IDF) curves. This research study evaluates IDF curves changes of the Baghmalek climatic station in the southwest of Iran. A developed integrated method extracted the IDF curves using the Gumbel and log-Pearson III probability distributions and observed maximum annual precipitations. Durations of these precipitations are 15, 30, 45 minutes and 1,2,3,6 and 12 hours. For this purpose, this method utilizes the recorded precipitation data of the Baghmalek climatic station in a 40-year period (1974-2013). Then, mean square error method determines the probability distribution that has the best fitting with this data. The HadCM3 prepares precipitation data for a 30-year period (2021-2050) based on A1B, B1, and A2 scenarios. In addition, this method selects an optimum artificial neural network to extract maximum annual rainfall intensity for different durations and scenarios. Then, selected network and the chosen probability distribution produce IDF curves for different return periods and scenarios. Produced IDF curves for different scenarios are compared to IDF curves of a base time period. Because of increasing carbon dioxide and its greenhouse effect in these scenarios, rainfall intensity will increase for return periods less than 2.33 years, while it will decrease for return periods more than 2.33 years.