[H-CG27] [EE] Coupled Human-Water Dynamics across Scales: Observations, Understanding, Modeling, and Management

[HCG27-12] Climate change risk assessment by Integrated Terrestrial Model: a bio-geophysical land surface model with human components

*Tokuta Yokohata¹, Akihiko Ito¹, Naota Hanasaki¹, Gen Sakurai², Tsuguki Kinoshita³, Toshichika Iizumi², Yoshimitsu Masaki⁴, Tomoko Nitta⁵, Yadu Pokhrel⁶, Yusuke SATOH⁷, Seita Emori¹ (1.National Institute for Environmental Studies, 2.National Agriculture and Food Research Organization, 3.Ibaraki University, 4.Hirosaki University, 5.University of Tokyo, 6.Michigan State University, 7.International Institute for Applied System Analysis)

Keywords:Climate change, Water resources, Land use

Future climate changes possibly affect eco-system services, water resources, food production, energy supply, etc. It is important to understand the interaction between the changes in these complicated factors. In the present study, we develop an integrated terrestrial model which describes the natural biogeophysical environment as well as human activities. In the integrated model, a global vegetation model VISIT (Ito et al. 2012), water resource model H08 (Hanasaki et al. 2008, Pokhrel et al. 2012), crop growth model PRYSBI2 (Sakurai et al. 2015), and land use model TeLMO (Kinoshita et al., in preparation) are coupled to a land surface model MATSIRO (Takata et al. 2003, Nitta et al. 2014), which is a component of global climate model MIROC (Watanabe et al. 2010). Output variables of each sub-model are passed to other sub-models during the time integration. The time intervals of variable exchange are from hourly to monthly or yearly. For example, the crop yields [ton/ha] calculated by PRYSBI2 is used in TEMO which calculate the land use change (crop or natural vegetation area) of next year. The projected land-use map is used in all other sub-models. The water resource model H08 considers the irrigation process (water withdrawal from rivers) as well as dam operations in large rivers, which affects the state of the soil moisture and the river flows in the land surface model. We will present the state of the model development, and results from the historical and future simulation. In the historical simulation, we validated the model output such as river flow, irrigated water, crop yield, and ecosystem productions by comparing to the observed or reanalysis data. Based on the future simulation, we also assessed the risk of future climate change by investigating the relationship of possible cropland area expansion and crop productions and so on.