D4PDF: large-ensemble and high-resolution climate simulations for global warming risk assessment

Masayoshi Ishii,Nobuhito Mori

doi:10.1186/s40645-020-00367-7

Masayoshi Ishii, Nobuhito Mori

Open Access

https://doi.org/10.1186/s40645-020-00367-7

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Abstract

A large-ensemble climate simulation database, which is known as the database for policy decision-making for future climate changes (d4PDF), was designed for climate change risk assessments. Since the completion of the first set of climate simulations in 2015, the database has been growing continuously. It contains the results of ensemble simulations conducted over a total of thousands years respectively for past and future climates using high-resolution global (60 km horizontal mesh) and regional (20 km mesh) atmospheric models. Several sets of future climate simulations are available, in which global mean surface air temperatures are forced to be higher by 4 K, 2 K, and 1.5 K relative to preindustrial levels. Nonwarming past climate simulations are incorporated in d4PDF along with the past climate simulations. The total data volume is approximately 2 petabytes. The atmospheric models satisfactorily simulate the past climate in terms of climatology, natural variations, and extreme events such as heavy precipitation and tropical cyclones. In addition, data users can obtain statistically significant changes in mean states or weather and climate extremes of interest between the past and future climates via a simple arithmetic computation without any statistical assumptions. The database is helpful in understanding future changes in climate states and in attributing past climate events to global warming. Impact assessment studies for climate changes have concurrently been performed in various research areas such as natural hazard, hydrology, civil engineering, agriculture, health, and insurance. The database has now become essential for promoting climate and risk assessment studies and for devising climate adaptation policies. Moreover, it has helped in establishing an interdisciplinary research community on global warming across Japan.

Highlights

Following the series of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report published in 2013 and 2014, the Paris Agreement was adopted in December 2015
1.1 A brief history In 1989, Meteorological Research Institute (MRI) started researches on global warming. They first conducted climate simulations by an atmospheric model coupled to a slab ocean model (Noda and Tokioka 1989), and the result was provided to the first IPCC assessment report
3 Conclusions The large-ensemble and high-resolution climate simulation database called d4PDF was developed for extensive use in impact/risk assessment and policy decision-making for adaptation measures

Summary

Introduction

Following the series of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report published in 2013 and 2014, the Paris Agreement was adopted in December 2015. From 2002 to 2016, enhanced global warming studies were conducted under three Japanese research programs supported by the Japanese ministry, MEXT, in which the University of Tokyo, JAMSTEC, MRI, NIES, Kyoto University, and other institutes participated These programs developed climate models (Hasumi and Emori 2004; Nozawa et al 2007; Watanabe et al 2010; Tatebe et al 2019), a high-resolution coupled atmosphere and ocean model (Sakamoto et al 2012), and ambitious earth system models (Kawamiya et al 2005; Watanabe et al 2011; Hajima et al 2020) that were used for future climate projections. Event attribution studies requiring large-ensemble model simulations (e.g., Watanabe et al 2013) were conducted by the Program for Risk Information on Climate Change (SOUSEI, from FY2012 to FY2016)

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