2.2 Coupling CAS-LSM with CAS-FGOALS-g3
CAS-FGOALS-g3 is a global climate model consisting of atmosphere (Li et al. 2019), land (Xie et al. 2018), oceans (LICOM) and a sea-ice model (Holland et al. 2012). A general overview of CAS-FGOALS-g3 has been provided by Li et al. (in preparation). The land component of CAS-FGOALS-g3 was CAS-LSM (Xie et al. 2018), which included the aforementioned processes including GLF (Xie et al. 2012; Zeng et al. 2016a, 2016b, 2018), human water exploitation (Zou et al. 2014, 2015; Zeng et al. 2016b, 2017), FTFs (Gao et al. 2016, 2019), river nitrogen transport and human water use (Liu et al. 2019), and urban planning. Additional input land-use data sets have also been included in CAS-LSM, and the human water use, urban water use and AHR, and anthropogenic nitrogen discharge are treated as forcing input data in the model.
The coupling of CAS-LSM into CAS-FGOALS-g3 (Fig. 1) was based on CPL7 developed at the National Center for Atmospheric Research (NCAR). Compared with CPL6 (Craig et al. 2005), CPL7 possessed improved memory and performance scaling that could support much higher resolution configurations. In addition, CPL7 had more sophisticated computing resource control and a single executable, which allowed the models to run flexibly and simplified the machine requirements for the dispatcher. The land component communicated both state information and fluxes with the atmosphere component through the coupler during every atmospheric time step.