Evaluation of Climate in CMIP6 Models over Two Third Pole Subregions with Contrasting Circulation Systems

Abstract Reliable simulations of historical and future climate are critical to assessing ecological hydrological responses over the Third Pole (TP). In this study, we evaluate temperature precipitation 18 models from Coupled Model Intercomparison Project Phase 6 (CMIP6) in southeastern TP (SETP) upstream Amu Darya Syr (UAS) regions, two typical subregions dominated by Indian summer monsoon system westerlies, respectively. Comparison against station observations suggests that CMIP6 generally capture intra-annual variability spatial pattern both subregions. However, wetting cold biases observed CMIP5 still persist CMIP6; annual is underestimated most overestimated all models. Multi-model average SETP UAS 1.18°C 0.32°C, respectively, wet 119% 46%, We further analyze projections under SSP1-2.6, SSP2-4.5, SSP5-8.5 scenarios. Both projected experience significant warming 2015–2100, with trends 34%–42% 40%–50% higher than global trend, suggest trend will slow down SSP1-2.6 SSP2-4.5 but intensify 2050–2100. Monsoon-dominated a stronger entire period, especially (cf. winter westerlies-dominated UAS). Concurrently, drying found during 2050–2100 SSP5-8.5, suggesting intensified uneven distributions seasonal based on projections.