East Asian summer rainfall projection and uncertainty under a global warming scenario

Abstract

This work investigated the simulation and future changes in East Asian summer mean rainfall, interannual variability, and associated uncertainty based on the historical and representative concentration pathway (RCP) 4.5 runs of 26 CMIP5 models. It is noted that the present‐day mean rainfall was well simulated by most of the models, though underestimation is over the Meiyu/Baiu/Changma (MBC) rainfall belt, and overestimation is in the western North Pacific (WNP). Nevertheless, it is still a challenge for the CMIP5 models to well simulate the interannual variability. The approach of the multi‐model ensemble greatly improves the credibility of model simulations, especially for the rainfall variability. The East Asian summer rainfall is projected to a relatively consistent increase in the near future, while the spatial distributions of the summer rainfall changes by the end of the 21st century are similar to those in the near future, with twice magnitude of the mean rainfall amount increase. The rainfall changes are associated with the strengthened low‐level southerly wind over East China and intensified western North Pacific high. Also, the variation of rainfall interannual variability by the end of the 21st century over East Asia is larger than that in the near future, with similar spatial patterns. It may imply that the stronger rainfall interannual variability is associated with the increased mean rainfall amount in the future. The inter‐model spreads of both the mean and interannual variability changes are larger in the low latitudes than in the high latitudes over East Asia. The signal‐noise‐ratio (SNR) is largely determined by the rainfall change (signal) in the future. Lower SNR of interannual variability than that of mean rainfall over East Asia implies that the CMIP5 models are more robust to a certain extent in simulating the summer mean rainfall change in East Asia than the change of interannual variability.

Impacts of Anthropogenic Heat and Building Height on Urban Precipitation Over the Seoul Metropolitan area in Regional Climate Modeling

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In East Asia, heavy precipitation occurs in summer under the influence of the East Asian summer monsoon and typhoons with strong winds (Lee et al, 2017;Liu et al, 2020;Son et al, 2017). Moreover, as global warming intensifies, numerous studies have predicted an increase in summer precipitation in East Asia (Kim et al, 2018;Park et al, 2020).

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Future precipitation changes in three key sub-regions of East Asia: the roles of thermodynamics and dynamics

“…For example, to enhance the credibility of projections of tropical Pacific SST warming, a novel method of spatial emergent constraints with the ensemble pattern regression method has been employed to reduce the common change bias (Huang and Ying 2015b). Similarly, the simulated bias from the EASM intensity and associated precipitation has been corrected to give a more reliable projection under global warming of 1.5 ℃ or 2 ℃ (Liu et al 2020). Therefore, a bias-corrected method such as emergent constraints can be used to reduce the large spread in the dynamic component in future analysis.…”

“…The inter-model SD (σ) of changes is employed to quantify the inter-model spread. To examine the credibility of changes projected by the MMM, the signal-to-noise ratio (SNR), defined as the ratio of changes projected by MMM (implying signal) to inter-model spread (σ, implying noise or uncertainty) is used in this study (Long et al 2016;Zhou et al 2018;Liu et al 2020). The model agreement is the percentage of changes projected by the individual models that agree with the sign of changes projected by MMM.…”

Enhanced Monsoon‐Driven Upwelling in Southeast Asia During the Little Ice Age

“…Our coral record shows oligotrophication in the SCS since the LIA, but also indicates that the nutrient dynamics of the SCS are tightly linked to the strength of the East Asian Summer Monsoon winds. With ongoing anthropogenic climate change, the East Asian Summer Monsoon is generally expected to intensify and become more variable (Liu et al., 2020; Pachauri et al., 2014; Sun & Ding, 2010), potentially returning nutrient conditions to those seen during the initial onset of the LIA. The implication of our results is therefore that climate change‐driven intensification of summer monsoon upwelling may lead to increases in nutrient supply to the SCS.…”