An Introduction to the Coupled Model FGOALS1.1-s and Its Performance in East Asia

The spectral version 1.1 of the Flexible Global Ocean--atmosphere--landSystem (FGOALS1.1-s) model was developed in the State Key Laboratory ofNumerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamicsat the Institute of Atmospheric Physics (LASG/IAP). This paper reports themajor modifications to the physical parameterization package in itsatmospheric component, including the radiation scheme, convection scheme,and cloud scheme. Furthermore, the simulation of the East Asian SummerMonsoon (EASM) by FGOALS1.1-s is examined, both in terms of climatologicalmean state and interannual variability.The results indicate that FGOALS1.1-s exhibits significant improvements inthe simulation of the balance of energy at the top of the atmosphere: thenet radiative energy flux at the top was 0.003 W m^-2 in the 40 yearsfully coupled integration. The distribution of simulated sea surfacetemperature was also quite reasonable, without obvious climate drift.FGOALS1.1-s is also capable of capturing the major features of theclimatological mean state of the EASM: major rainfall maximum centers, theannual cycle of precipitation, and the lower-level monsoon circulation flowwere highly consistent with observations in the EASM region.Regarding interannual variability, simulation of the EASM leading patternsand their relationship with sea surface temperature was examined. Theresults show that FGOALS1.1-s can reproduce the first leading pattern of theEASM and its close relationship with the decaying phase of the ENSO.However, the model lacked the ability to capture either the second majormode of the EASM or its relationship with the developing phase of the ENSO.