Tropical atmospheric dynamics differ fundamentally from midlatitude dynamics due to the weak Coriolis effect near the equator. In the tropics, horizontal temperature gradients remain weak (the 'weak temperature gradient' approximation), so diabatic heating from moist convection is primarily balanced by adiabatic cooling from vertical motion (ascent), not by horizontal temperature gradients (which instead dominate midlatitude thermal wind balance).
In the deep tropics, because the Coriolis parameter is small, geostrophic/thermal-wind balance (which relies on horizontal temperature gradients balancing atmospheric motion) is weak or absent;...
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