Fundamental framework and experiments of the third generation of IAP/LASG world ocean general circulation model

• Published in: Advances in Atmospheric Sciences
• Main Authors: Jin, XZ, Zhang, XH, Zhou, TJ
• Other Authors: Jin, XZ (reprint author), Chinese Acad Sci, Inst Atmospher Phys, LASG, State Key Lab Numer Modeling Atmospher Sci & Geop, Beijing 100080, Peoples R China., Chinese Acad Sci, Inst Atmospher Phys, LASG, State Key Lab Numer Modeling Atmospher Sci & Geop, Beijing 100080, Peoples R China., Peking Univ, Dept Geophys, Beijing 100871, Peoples R China.
• Format: Journal/Newspaper
• Language: English
• Published: 大气科学进展英文版 1999
• Subjects: ocean general circulation model; thermocline; isopycnal mixing; THERMOHALINE CIRCULATION; CLIMATE; SIMULATION; SYSTEM; North Atlantic Deep Water; North Atlantic
• Online Access: https://hdl.handle.net/20.500.11897/214768; https://doi.org/10.1007/BF02973082

A new generation of the IAP / LASG world ocean general circulation model is designed and presented based on the previous 20-layer model, with enhanced spatial resolutions and improved parameterizations. The model uses a triangular-truncated spectral horizontal grid system with its zonal wave number of 63 (T63) to match its atmospheric counterpart of a T63 spectral atmosphere general circulation model in a planned coupled ocean-atmosphere system. There are 30 layers in vertical direction, of which 20 layers are located above 1000 m for better depicting the permanent thermocline. As previous ocean models developed in IAP / LASG, a free surface (rather than "rigid-lid" approximation) is included in this model. Compared with the 20-layer model, some more detailed physical parameterizations are considered, including the along / cross isopycnal mixing scheme adapted from the Gent-MacWilliams scheme. The model is spun up from a motionless state. Initial conditions for temperature and salinity are taken from the three-dimensional distributions of Levitus' annual mean observation. A preliminary analysis of the first 1000-year integration of a control experiment shows some encouraging improvements compared with the twenty-layer model, particularly in the simulations of permanent thermocline, thermohaline circulation, meridional heat transport, etc. resulted mainly from using the isopycnal mixing scheme. However, the use of isopycnal mixing scheme does not significantly improve the simulated equatorial thermocline. A series of numerical experiments show that the most important contribution to the improvement of equatorial thermocline and the associated equatorial under current comes from reducing horizontal viscosity in the equatorial regions. It is found that reducing the horizontal viscosity in the equatorial Atlantic Ocean may slightly weaken the overturning rate of North Atlantic Deep Water. Meteorology & Atmospheric Sciences SCI(E) 中国科学引文数据库(CSCD) 47 ARTICLE 2 197-215 16