Contributions of GCM/RCM Uncertainty in Ensemble Dynamical Downscaling for Precipitation in East Asian Summer Monsoon Season

Abstract

Targeting to East Asian summer monsoon for the first time, this study presents an assessment of projection uncertainty in ensemble dynamical downscaling (DDS) simulations. Based on 12-member DDS simulations comprised of three global climate models (GCMs) and four regional climate models (RCMs), we evaluate contributions of GCM and RCM uncertainty to the total uncertainty of summertime precipitation projections around Japan. Our results show that contribution of RCM uncertainty can be comparable to that of GCM uncertainty in magnitudes. This finding draws a distinction from the past studies showing the dominance of GCM uncertainty. Most notably, our results show that RCM uncertainty for number of precipitating days appears around and over the land. RCM uncertainty for precipitation amounts also shows a dependence on topography but to a lessor degree. These RCM uncertainty characteristics are potentially linked to the difference in various RCM configurations such as physics schemes and model topography. In contrast, GCM uncertainty mostly appears over the ocean, which can be attributed to the difference in the GCM's future projections of East Asian summer monsoon. Our finding may be of an importance for water disaster and water resource management with DDS.

Partitioning uncertainty components of mean climate and climate change in a large ensemble of European regional climate model projections

“…It can be seen that this field is dominated by climate change, that interannual variability is moderate compared to the statistical effects of model choice, that the choice of GCM is very important over the Atlantic ocean, and that the contribution from the RCM choice is smaller than the GCM term and most important over the eastern part of the domain and in some mountain regions. Similar relatively strong influence from RCMs in mountainous regions was found by Suzuki-Parker et al (2018) in their analysis of precipitation over Southeast Asia including Japan. Corresponding plots of other seasons and fields can be found in the Supplementary Material Figs S11, S14, and S18.…”

“…Evin et al 2019). An exceptional case with a completely filled GCM-RCM matrix is the study by Suzuki-Parker et al (2018) analysing a 12-member matrix with four RCMs downscaling three different GCMs over East Asia.…”

Selecting Future Climate Projections of Surface Solar Radiation in Japan

“…However, while analyses of temperature and precipitation changes in Japan are abundant (e.g., Ogata et al 2014, Nayak et al 2017, Suzuki-Parker et al 2018, Yokoyama et al 2019, studies on the future projections of the SW in Japan are limited. Wild et al (2015) examined the global-scale future projections of the SW of the Coupled Model Inter-comparison Project Phase 5 (CMIP5, Taylor et al 2012) ensemble up to the year 2049 under representative concentration pathway 8.…”

Contribution of Historical Global Warming to Local‐Scale Heavy Precipitation in Western Japan Estimated by Large Ensemble High‐Resolution Simulations

“…A dynamical downscaling from global climate simulations using regional climate models (RCMs) is a useful method to simulate specific regional climate with higher resolutions. Previous studies have conducted the future projection of summertime precipitation using multiple RCMs and GCMs (e.g., Inatsu et al, ; Nayak et al, ; Suzuki‐Parker et al, ). The pseudo global warming downscaling method (Kimura & Kitoh, ) is one of the dynamical downscaling methods, in which climatological changes are superimposed to the current atmospheric or ocean conditions.…”