大气科学学报2025，Vol.48Issue(2)：240-254,15.DOI:10.13878/j.cnki.dqkxxb.20240416001
CMIP6 HighResMIP模式对青藏高原东侧极端降水的模拟评估及热动力效应
Assessment of extreme precipitation simulations over the eastern Qinghai-Xizang Plateau using CMIP6 HighResMIP models:thermodynamic and dynamic contributions
摘要
Abstract
The eastern slope of the Qinghai-Xizang Plateau(ESQP)features complex topography and substantial elevation gradients,making it a region of intricate climate dynamics.This study assesses the ability of the Coupled Model Intercomparison Project Phase 6(CMIP6)High-Resolution Model Intercomparison Project(HighResMIP)models to simulate precipitation over the EQSP,with a focus on comparing high-resolution(HR)and low-resolution(LR)models in capturing both annual and extreme precipitation events.Using data from 1985 to 2014,including historical simulations and observational datasets,the study evaluates extreme precipitation indi-ces such as R10mm(heavy precipitation days)and Rx1day(maximum 1-day precipitation).Results show that both HR and LR models successfully capture the general spatial distribution of annual precipitation,which increa-ses from northwest to southeast across the region.However,HR models exhibit significant improvements over LR models in reducing biases and improving simulation accuracy.Specifically,the annual precipitation bias is reduced from 1.05 mm·d-1 in LR models to 0.96 mm·d-1 in HR models,demonstrating the benefits of increased reso-lution in minimizing simulation errors.For extreme precipitation events,HR models outperform LR models in both occurrence and intensity representation.The R10mm index shows a 6％reduction in relative error for HR models compared to LR models,while the Rx1day index exhibits a 5％improvement in HR model performance.These improvements are particularly notable in the Sichuan Basin,a region historically challenging to simulate due to its complex terrain and variable moisture conditions.Further analysis investigates the thermodynamic and dynamic contributions to differences between HR and LR model simulations using a physical scaling diagnostic equation.Results indicate that dynamic effects account for 91％of the improvements observed in HR models,while thermo-dynamic effects contribute only 8％.This suggests that higher resolution enhances the representation of atmospheric circulation,vertical motion,and moisture transport-key processes in extreme precipitation simulation.HR models demonstrate improved simulations of cyclonic flows and moisture convergence in the Sichuan Basin,leading to reduced wet biases in high-altitude areas and better overall accuracy in extreme precipitation simula-tions.Despite these advancements,certain biases persist,particularly over the Yunnan-Guizhou Plateau,where pre-cipitation remains difficult to simulate accurately.This highlights the need for continued improvements in model physics and resolution to better capture the complex atmospheric and topographic influences on precipitation pat-terns.The findings of this study have important implications for climate risk assessments in the ESQP,particularly in relation to extreme precipitation events and associated hazards such as floods and landslides.The enhanced ac-curacy of HR models is crucial for understanding future precipitation changes under global warming.As extreme precipitation events are expected to intensify with climate change,further improving climate model simulations is essential for effective risk management and policy development.In conclusion,this research demonstrates that in-creasing model resolution significantly enhances precipitation simulation accuracy,particularly for extreme events,over the eastern Qinghai-Xizang Plateau.The improvements in HR models,particularly in capturing dynamic at-mospheric processes,provide valuable insights into the regional climate dynamics of this complex terrain.Howev-er,challenges remain in accurately simulating precipitation over specific areas,underscoring the need for further advancements in model development.Future research should focus on refining the representation of atmospheric circulation and moisture processes in regions with complex topography and exploring multi-model ensemble ap-proaches to reduce uncertainties in climate projections.关键词
青藏高原/CMIP6 High-ResMIP/极端降水/物理尺度诊断方程Key words
the Qinghai-Xizang Plateau/CMIP6 HighResMIP/extreme precipitation/physical scaling diagnostics引用本文复制引用
王康宁,陈权亮,葛非,林芷叶..CMIP6 HighResMIP模式对青藏高原东侧极端降水的模拟评估及热动力效应[J].大气科学学报,2025,48(2):240-254,15.基金项目
国家自然科学基金项目(U2442210 （）
42375047) （）
四川省自然科学基金项目(2024NSFTD0017 （）
2024NSFSC0064) （）
高原与盆地暴雨旱涝灾害四川省重点实验室开放研究基金项目(SZKT202304) （SZKT202304）
