Atmospheric Tides Appearing in a Global Atmospheric General Circulation Model

[摘要] Atmospheric tides induced in a global atmospheric general circulation model in January are analyzed. The model produces detailed structure in the thermal forcings of diurnal and semi-diurnal modes within the planetary boundary layer (PBL) in the subtropics and within the mid-troposphere in the tropics. Compared with the forcings by Forbes (1982a, b), the model gives larger ones in the lower part of the troposphere for both modes. The thermal forcings of diurnal and semi-diurnal tides within the stratosphere roughly agree with the forcings by Forbes (1982a, b).The model produces tidal forcings other than the migrating tides, such as (ƒ=-1, m=5), (ƒ=1, m=3), (ƒ=-1, m=9), (ƒ=1, m=1), ..., where _??_ is the frequency in day-1 and m is the zonal wavenumber. Such non-migrating modes* have large thermal forcings within the PBL and the mid-troposphere in the tropics. Strong diurnal heating over land in low latitudes essentially forces them.

[学科分类] 大气科学