The Flexible Global Ocean‐Atmosphere‐Land System Model Grid‐Point Version 3 (FGOALS‐g3): Description and Evaluation

Abstract

This paper introduces the Flexible Global Ocean‐Atmosphere‐Land System Model: Grid‐Point Version 3 (FGOALS‐g3) and evaluates its basic performance based on some of its participation in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) experiments. Our results show that many significant improvements have been achieved by FGOALS‐g3 in terms of climatological mean states, variabilities, and long‐term trends. For example, FGOALS‐g3 has a small (−0.015°C/100 yr) climate drift in 700‐yr preindustrial control (piControl) runs and smaller biases in climatological mean variables, such as the land/sea surface temperatures (SSTs) and seasonal soil moisture cycle, compared with its previous version FGOALS‐g2 during the historical period. The characteristics of climate variabilities, for example, Madden‐Julian oscillation (MJO) eastward/westward propagation ratios, spatial patterns of interannual variability of tropical SST anomalies, and relationship between the East Asian Summer Monsoon and El Niño–Southern Oscillation (ENSO), are well captured by FGOALS‐g3. In particular, the cooling trend of globally averaged surface temperature during 1940–1970, which is a challenge for most CMIP3 and CMIP5 models, is well reproduced by FGOALS‐g3 in historical runs. In addition to the external forcing factors recommended by CMIP6, anthropogenic groundwater forcing from 1965 to 2014 was incorporated into the FGOALS‐g3 historical runs.

Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations

“…Palaeoenvironmental evidence also hints at an increased zonal SST gradient in the equatorial Pacific during the mid-Holocene (Koutavas et al, 2002;Linsley et al, 2010;Carré et al, 2014), whilst the PMIP4-CMIP6 ensemble yields a slight decrease in the gradient (Table S2). Analysis of equatorial Pacific climate change and variability finds little evidence for the simulated relationship between SST gradient and ENSO variance in the PMIP4-CMIP6 ensemble (Brown et al, 2020).…”

Description and Climate Simulation Performance of CAS‐ESM Version 2

“…CAS-ESM 2 contains significantly changed physical parameterizations in addition to the IAP dynamical core in the atmospheric model. CAS-ESM has several sister versions of a climate model, the CAS-Flexible Global Ocean-Atmosphere-Land System (FGOALS) model (Guo et al, 2020;Li et al, 2020). FGOALS has contributed to each phase of the past Coupled Model Intercomparison Project (CMIP).…”

The GAMIL3: Model Description and Evaluation

“…All the parameters in GAMIL are finally determined according to their performance (including the ENSO) in the piControl run by the coupled model, and the ENSO amplitude (the standard deviation of the Niño3 index) is too strong in the piControl run before tuning FGOALS-g3 version (about 1.8 K). Through the parameters tuning to enhance the negative heat flux feedback, there is about 0.3-K decrease of the ENSO amplitude, together with the tuning of ocean model coupling intervals and ocean parameters, resulting to a relatively reasonable ENSO amplitude (about 1.0 K) in FGOALS-g3 (Li et al, 2020). Figure 19 shows anthropogenic aerosol ERF and its two main components, that is, instantaneous radiative forcing from the direct effect (RFari) and effects on cloud radiative forcing.…”