The NCEP Climate Forecast System version 2 (CFSv2; Saha et al. 2013) is a state-of-the-art coupled climate model developed by the National Center for Environmental Prediction (NCEP), USA and it has been implemented to the Prithvi High Performance Computer (HPC) at Indian Institute of Tropical Meteorology (IITM), Pune with support from the Monsoon Mission Project of Ministry of Earth Science, Govt. of India. It is a fully coupled ocean- atmosphere-land model with advanced physics, increased resolution and refined initialization as compared to earlier version (CFSv1).
The atmospheric component of CFSv2 is Global Forecast System (GFS) with spectral resolution of T126 and 64 hybrid vertical levels (Moorthi et al. 2001; Yang et al. 2006) and the ocean component is Geophysical Fluid Dynamics Laboratory (GFDL) Flexible Modeling System (FMS) Modular Ocean Model version 4p0d (MOM4; Griffies et al. 2004). The convective parameterization utilizes simplified Arakawa-Schubert convection with momentum mixing. The model also implements orographic gravity wave drag based on Kim and Arakawa (1995) approach and sub-grid scale mountain blocking (Lott and Miller 1997).
The model employs Rapid radiative transfer model shortwave radiation with maximum random cloud overlap (Iacono et al. 2000; Clough et al. 2005). In addition, it has a four layer NOAH land surface model (Ek et al. 2003) and a two layer dynamical sea ice model (Wu et al. 1997; Winton 2000) coupled together with the Atmosphere and Ocean components in Earth System Modeling Framework (ESMF).