Future changes in precipitation extremes across China based on CMIP6 models

Abstract

A comparison assessment of model capabilities in simulating precipitation extremes across China was first implemented by using 30 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and using 36 CMIP6 models. The results indicate that the multi‐model median ensembles (MME) of both the CMIP5 and CMIP6 models can reasonably reproduce the climate means for the period from 1986 to 2005, and the biases are lower in most CMIP6 models compared to the CMIP5 models, especially over southern China. To provide further comparisons, 14 CMIP6 models are selected and compared with their predecessors in CMIP5. The results show that the CMIP6 models generally exhibit superior skill in simulating the extreme precipitation indices over China. The model spreads for most of the extreme indices in the CMIP6 version are also smaller. Additionally, the MMEs of the two CMIPs outperform individual models. However, some CMIP6 models also exhibit weaker skill levels in simulating some particular indices compared with those in CMIP5, which merits further investigation. The results from seven reanalyses further show large uncertainties for these indices; therefore, care should be taken in comparison with reanalyses. For future changes in precipitation extremes, total wet day precipitation (PRCPTOT), maximum 5‐day precipitation (RX5day) and very heavy precipitation days (R20mm) are projected to clearly increase across China over the coming century under the shared socioeconomic pathway (SSP) 2‐4.5 and SSP5‐8.5 scenarios. However, the dry condition index of CDD exhibits a decreasing tendency in the future, which implies that the dry conditions induced by precipitation anomalies will be mitigated. However, large uncertainties are still observed for future changes, which are primarily sourced from inter‐model and scenario variabilities, especially for the projected changes at the end of the 21st century.

Simulation and Projection of Climate Extremes in China by a Set of Statistical Downscaled Data

“…It would be up to 2 days and 3–4 days over southern China in the mid-term and long-term periods. The above results are consistent with the conclusions of Xu et al [ 40 ] and Zhu et al [ 41 ].…”

Future Changes in Precipitation Extremes over East Africa Based on CMIP6 Models

“…Although the examination of the sources of the uncertainty in projections was out of scope of this study, numerous studies have indicated that internal variability in the model accounts for most sources of uncertainty as compared to scenario or inter-model uncertainty [86]. For instance, a recent study that examined future changes in precipitation extremes across China based on CMIP6 models noted that uncertainty in future projections were mainly sourced from the internal variability, which accounted for more than 50% of the total variance in the indices, except for the CDD [73].…”

“…Additionally, uncertainty in the model spread is shown based on the 25th to 75th interquartile range for SSP2-4.5 and SSP5-8.5 scenarios for the precipitation extremes. A similar approach has been used in a recent study that explored the future changes in precipitation over China based on CMIP6 models [73]. The precipitation indices of PRCPTOT, R20 mm, and SDII are projected to significantly increase under both scenarios (Figure 4a,c,d).…”

Long-Term Projection of Water Cycle Changes over China Using RegCM

“…The projected increase in precipitation in the Yellow River and Haihe River Basins can also be observed in a CMIP6 GCM ensemble according to Tian et al [54]. It is worth noting that although the projected precipitation increase in the Tarim Basin is within 0.3 mm/day, the percentage change could be large considering its low annual average total precipitation, which is why several studies (e.g., [55,56]) identified it as an area vulnerable to climate change. Precipitation increase has been shown to be among the driving factors for the increased flood frequency in the Tarim River Basin since the 1980s [57]; the increase in future precipitation as projected by this and the previous studies may indicate increased flood risks in this area, which suggests the need for relevant flood prevention measures.…”