Climate Change Research

Climate Change Research

Statistical Post-processing of the Data-Driven Model for Estimating Spatial Precipitation Changes in the Middle Zagros

Document Type : Original Article

Author
Mohammad Saeed Najafi
Assistant Professor, Water Research Institute, Ministry of Energy, Tehran, Iran
10.30488/ccr.2025.555716.1310
Abstract
This study aims to spatially estimate precipitation in the Central Zagros region based on the relationship between precipitation and geographical factors, using data-driven models, and highlighting the importance of statistical post-processing in model outputs. To model precipitation, the Artificial Neural Network (ANN) method was employed. The most suitable network structure was determined using the LM training algorithm. The resulting model demonstrates an explanatory power of 50% (R2=0.5) for the spatial estimation of precipitation in the Central Zagros. To enhance model accuracy, various error correction methods were used for post-processing the model outputs. This stage resulted in an optimization of the simulations by 5 to 10 percent. Among the methods investigated, the Quantile Mapping (QM) method exhibited the best performance, increasing the final correlation between the model simulations and observational values to 0.81. This optimization confirms the necessity of post-processing for correcting the systematic error of data-driven models to achieve the required accuracy in precipitation estimation and water resource management in complex mountainous regions. The results of this study indicated that elevation is the most important controlling factor of precipitation in the Central Zagros region, with a strong and positive relationship between precipitation and elevation. However, the analysis of elevational profiles revealed that the maximum precipitation occurs at an elevation of approximately 2500 meters up to the ridge line, and does not exactly coincide with the maximum elevation at the ridge line. This pattern emphasizes that the most effective orographic condensation processes occur at a level below the summit and may extend up to the ridge line.
Keywords
Precipitation Elevation Data
driven model Bias correction Middle Zagros

Subjects

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