Global distribution of land surface hydrological variables and associated energy and water budget components are calculated by land surface scheme SiBUC using GSWP-2 dataset. The SiBUC model uses mosaic approach to incorporate all kind of land-use into LSS, and it has been developed, validated, and applied mainly in Japan and China region. SiBUC has three sub-models for green area(vegetation), urban area, and water body. Furthermore, several kinds of vegetation is also allowed to coexist in the same grid. The vegetation scheme is basically same as SiB, but some simplification from original SiB was done.

A Rice paddy field is so unique and specific since it can store plenty of water above soil surface. In the original version of SiB and most of the LSSs currently implemented in numerial weather prediction models and global climate models, there is no framework to treat rice paddy field properly. In irrigated paddy field, water is controlled/operated differently according to growing stage of rice. Therefore, paddy field scheme, which has water layer above soil surface, and which can treat artificial water irrigation/drainage was developed and implemented into green area model.

In another words, main difference of SiBUC from other LSSs is in the treatment of irrigation water in paddy field. Then, the result of the GSWP-2 run will be analyzed mainly in the following aspects. 1. The difference between paddy field and other vegetation in the time series of soil moisture and energy balance. 2. The relationship between inter-annual variation of irrigated water and other meteorological variables