The circulation patterns induced by mobile global heating are investigated by using linearized shallow-water equations on the sphere when the Rayleigh friction rate (α) is different from the Newtonian cooling rate (
c). The other parameters involved in this system are Lamb parameter (
i. e., the parameter representing the effect of planetary rotation) and the velocity of the heat source. Numerical solutions for a wide range of these parameters are obtained directly from the simultaneous equations which are calculated from the shallow-water equations by expanding variables and the heating distribution in a series of normalized spherical harmonics.
When the motion of the heat source is not fast, the circulation patterns obtained strongly depend on α rather than
c. The circulation, which is zonally uniform only in the height field, appears only when both α and
c are sufficiently small. Further, both the height and divergence fields become zonally uniform when α is sufficiently large,
c is small. This pattern never appears for steady heating. The circulation patterns also become zonally uniform for rapidly mobile heating, unless
c is large. These results suggest that the assumption of α=
c is applicable to a planetary atmosphere of α≠
c such as the earth's one, if α is neither extremely smaller nor larger than
c.
This investigation may be applied to the Venusian lower atmosphere where α is supposed to be considerably larger than
c. When the relaxation time of the dynamical damping process (=1/α) is shorter than 100 days, it is suggested that the direct circulation between the day and night sides appears independent of
c.
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