Consistency Assessment of CORDEX Multi-Domain Simulations Over the Tibetan Plateau Using REMO

Abstract

The Tibetan Plateau (TP), often referred to as the Water Tower of Asia and the Third Pole, is undergoing rapid warming and wetting, making it a key focus of contemporary Earth System Science Research. Three Coordinated Regional Downscaling Experiment (CORDEX) domains: CORDEX-EAS-II, CORDEX-CAS-II and CORDEX-SAS-II, overlap over the TP, providing an opportunity to assess the sensitivity of CORDEX simulations to the domain choice in this region. In this study, we analyse the similarities and differences in the latest version of Regional Model (REMO) simulation across the three CORDEX domains at a spatial resolution of 25 km, focusing on climatology and climate extremes. The results show that the choice of simulation domain has minimal impact on REMO's climate and extreme climate simulations over the TP. Three-dimensional indicators reveal that the choice of domains primarily influences the temporal evolution for temperature simulations over the TP, with minimal effects on magnitudes and spatial patterns. For precipitation simulations, the choice of domains has a more pronounced effect on magnitudes than on temporal variation or spatial patterns. Additionally, significant seasonal biases are observed in REMO's simulation of wet days, with negative biases in summer linked to a lower frequency of 1–7 mm precipitation, while positive biases in other seasons are associated with an overestimation of moderate-to-heavy rainfall frequencies.