Doesn the friction over land kill tropical cyclones?
No, during landfall, the increased friction over land acts – somewhat contradictory – to both decrease the sustained winds and also to increase the gusts felt at the surface. The sustained winds are reduced because of the dampening effect of larger roughness over land (i.e. bushes, trees and houses over land versus a relatively smooth ocean). The gusts are stronger because turbulence increases and acts to bring faster winds down to the surface in short (a few seconds) bursts.
(Parts of this section are written by Sim Aberson.) No. During landfall, the increased friction over land acts – somewhat contradictory – to both decrease the sustained winds and also to increase the gusts felt at the surface (Powell and Houston 1996). The sustained (1 min or longer average) winds are reduced because of the dampening effect of larger roughness over land (i.e. bushes, trees and houses over land versus a relatively smooth ocean). The gusts are stronger because turbulence increases and acts to bring faster winds down to the surface in short (a few seconds) bursts. However, after just a few hours, a tropical cyclone over land will begin to weaken rapidly – not because of friction – but because the storm lacks the the moisture and heat sources that the ocean provided. This depletion of moisture and heat hurts the tropical cyclone’s ability to produce thunderstorms near the storm center. Without this convection, the storm rapidly fills.
No. During landfall, the increased friction over land acts – somewhat contradictory to expectations – to both decrease the sustained winds and also to increase the gusts felt at the surface (Powell and Houston 1996). The sustained (1 min or longer average) winds are reduced because of the dampening effect of larger roughness over land (i.e. bushes, trees and houses over land versus a relatively smooth ocean). The gusts are stronger because turbulence increases and acts to bring faster winds down to the surface in short (a few seconds) bursts. However, after just a few hours, a tropical cyclone over land will begin to weaken rapidly – not because of friction – but because the storm lacks the the moisture and heat sources that the ocean provided. This depletion of moisture and heat hurts the tropical cyclone’s ability to produce thunderstorms near the storm center. Without this convection, the storm rapidly fills. An early numerical simulation (Tuleya and Kurihara 1978) had shown that a
