May 6, 2024
Shapour Koohestani

Shapour Koohestani

Academic rank: Assistant professor
Address:
Education: PhD. in -
Phone: 9131483379
Faculty:

Research

Title
Projection of Climate Change Impacts on Precipitation Using Soft-Computing Techniques: A Case Study in Zayandeh-rud Basin, Iran
Type Article
Keywords
Downscaling, Supervised PCA, Climate change, Supervised learning
Researchers Shapour Koohestani, سيد سعيد اسلاميان, Jahangir Abedi Koupaei, َAli Asghar Besalatpour

Abstract

Due to the complexity of climate-related processes, accurate projection of the future behavior of hydro-climate variables is one of the main challenges in climate change impact assessment studies. In regression-based statistical downscaling processes, there are different sources of uncertainty arising from high-dimensionality of atmospheric predictors, nonlinearity of empirical and quantitative models, and the biases exist in climate model simulations. To reduce the influence of these sources of uncertainty, the current study presents a comprehensive methodology to improve projection of precipitation in the Zayandeh-Rud basin in Iran as an illustrative study. To reduce dimensionality of atmospheric predictors and capture nonlinearity between the target variable and predictors in each station, a supervised-PCA method is combined with two soft-computing machine-learning methods, Support Vector Regression (SVR) and Relevance Vector Machine (RVM). Three statistical transformation methods are also employed to correct biases in atmospheric large-scale predictors. The developed models are then employed on outputs of the Coupled Model Intercomparison Project Phase 5 (CMIP5) multimodal dataset to project future behavior of precipitation under three climate changes scenarios. The results indicate reduction of precipitation in the majority of the sites in this basin threatening the availability of surface water resources in future decades.