A Content-Based Database System for Large Ensemble Future Climate Simulations

Analyses of large ensemble data of future climate are quite useful in order to produce probabilistic future projection of climate change in various interdisciplinary fields related to, e.g., hydrology, civil engineering and adaptation planning for global warming. Ensemble data of "+2K future climate simulations" are currently generated by "Social Implementation Program on Climate Change Adaptation Technology" (SI-CAT) as a part of a database for Policy Decision making for Future climate change (d4PDF; Mizuta et al. 2016) produced by Program for Risk Information on Climate Change. Those data consist of global warming simulations and regional downscaling simulations around Japan. Considering that those data volumes are too large, i.e. a few petabytes, to download to a local computer of users, a user-friendly system is required to search and download data which satisfy requests of the users.

In order to provide functions to extract necessary data from +2K future climate simulations to the users, we developed "a database system for SI-CAT climate simulations" (SI-CAT DBS). Existing web-based search systems for climate simulations are designed to find data files using metadata associated with a data file itself. On the other hand, the SI-CAT DBS allows the users to extract necessary data using metadata associated with contents of a data file such as physical values. The SI-CAT DBS mainly consists of a relational database, a data download function and web-based user interface. Among the three main features, a key role is provided by the relational database using PostgreSQL which is designed to be registered temporally and spatially compressed data. The data download function allows the users to download temporally and spatially extracted data based on search results obtained by the relational database. In addition, the web-based user interface allows the users to easily use the relational database without knowledge about PostgreSQL. The SI-CAT DBS is currently in operational test on a server maintained by Data Integration and Analysis System Program (DIAS).

The SI-CAT DBS will be released on DIAS in fiscal year 2018. Techniques of the SI-CAT DBS might be quite useful for simulation, experimental and observational data in other research fields. We report current status of development and some case studies of the SI-CAT DBS.