First Institute of Oceanography, and Key Laboratory of Marine Science and Numerical Modeling, Ministry of Natural Resources, Qingdao 266061, China
Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
Shandong Key Laboratory of Marine Science and Numerical Modeling, Qingdao 266061, China
The National Key R&D Program of China under contract Nos 2018YFA0605701 and 2016YFB0201100, the National Natural Science Foundation of China under contract Nos 41941012 and 41821004, the Basic Scientiﬁc Fund for National Public Research Institute of China (ShuXingbei Young Talent Program) under contract No. 2019S06.
In this study, we introduced the Coupled Model Intercomparison Project Phase 6 (CMIP6) Ocean Model Intercomparison Project CORE2-forced (OMIP-1) experiment by using the First Institute of Oceanography Earth System Model version 2.0 (FIO-ESM v2.0), and comprehensively evaluated the simulation results. Unlike other OMIP models, FIO-ESM v2.0 includes a coupled ocean surface wave component model that takes into account non-breaking surface wave-induced vertical mixing in the ocean and effect of surface wave Stokes drift on air-sea momentum and heat fluxes in the climate system. A sub-layer sea surface temperature (SST) diurnal cycle parameterization was also employed to take into account effect of SST diurnal cycle on air-sea heat ﬂuxes to improve simulations of air-sea interactions. Evaluations show that mean values and long-term trends of significant wave height were adequately reproduced in the FIO-ESM v2.0 OMIP-1 simulations, and there is a reasonable fit between the SST diurnal cycle obtained from in situ observations and that parameterized by FIO-ESM v2.0. Evaluation of model drift, temperature, salinity, mixed layer depth, and the Atlantic Meridional Overturning Circulation shows that the model performs well in the FIO-ESM v2.0 OMIP-1 simulation. However, the summer sea ice extent of the Arctic and Antarctic is underestimated.
Figure 1. Drifts of horizontal and global mean potential temperature (unit: °C) and salinity (unit: psu). Drift is defined as deviation from the value obtained from the first model year. Dashed lines indicate the 62-year forcing cycle, corresponding to calendar years 1948-2009, which was repeated for 5 times.
Figure 2. Time series of annual mean (a) Atlantic Meridional Overturning Circulation (AMOC) (unit: 106 m3 s−1) maximum at 26.5°N, and (b) Global Meridional Overturning Circulation (GMOC) (unit: 106 m3 s−1) minimum between 2000 m depth and ocean bottom at 30°S. Dashed lines indicate the 62-year forcing cycle, corresponding to calendar years 1948-2009, that was repeated.
Figure 3. Biases of zonally averaged (a) temperature (unit: °C) and (b) salinity (unit: psu) from the last cycle of the FIO-ESM v2.0 OMIP-1 simulation relative to observed climatological values from World Ocean Atlas 2013 version 2 (WOA13 v2). Black contour is zonally averaged temperature and salinity from WOA13v2.
Figure 4. Biases of sea surface (a) temperature (unit: °C) and (b) salinity (unit: psu) from the last cycle of the FIO-ESM v2.0 OMIP-1 simulation relative to observed climatological values from World Ocean Atlas 2013 version 2 (WOA13 v2).
Figure 5. Simulated and observed mixed layer depth (MLD) (units: m) in summer and winter. Mixed layer depth is defined as the depth where ocean potential density deviates from its value at the surface by 0.03 kg m−3. The average of January, February and March is selected as the typical months for boreal winter (austral summer), and the average of July, August and September is selected as the typical months for boreal summer (austral winter). Observations are from de Boyer Montégut et al. (2004).
Figure 6. (a) Atlantic overturning streamfunction from the last cycle of the FIO-ESM v2.0 OMIP-1 simulation (units: 106 m3 s−1), (b) AMOC streamfunction profiles (brown line: FIO-ESM v2.0 OMIP-1 simulation, blue line: RAPID observations) at 26.5°N between 2004 and 2009, and (c) AMOC index (units: 106 m3 s−1) from the last cycle of the FIO-ESM v2.0 OMIP-1 simulation.
Figure 7. Diurnal amplitude (unit: °C) of sea surface temperature (SST) in (a) January and (b) July in the last cycle of the FIO-ESM v2.0 OMIP-1 simulation. Diurnal amplitude of SST is defined as the difference between maximum and minimum of SST in the same day.
Figure 8. Scatter plot of mean sea surface temperature (SST) diurnal amplitude (unit: °C) between 2002 and 2009 from the FIO-ESM v2.0 OMIP-1 simulation and from observations of 107 moorings as part of TOGA/COARE.
Figure 9. (a) Arctic and (b) Antarctic sea ice extent (SIE) from the last cycle of the FIO-ESM v2.0 OMIP-1 simulations and satellite-derived observations (units: 106 km2). Sea ice extent is calculated as the sum of the area where sea ice concentration exceeds 15%.
Figure 10. Simulated Arctic sea ice thickness (units: m) in March from (a) the last cycle of the FIO-ESM v2.0 OMIP-1 simulation and (b) Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS).
Figure 11. Average significant wave height (SWH) from 1979-2009 (units: m) obtained from (a, c) ERA5 reanalysis, and (b, c) the FIO-ESM v2.0 OMIP-1 simulation in (a, b) January and (c, d) July.
Figure 12. Linear trends of significant wave height (SWH) (units: %/decade) between 1985 and 2008. Dots indicate locations where linear trend exceeds 90% confidence level.