Geography Reference
In-Depth Information
(a)
z
r
(b)
z
r
Fig. 9.15
Meridional cross sections showing the relationship between surfaces of constant saturation
θ
e
(dashed contours; values decreasing as r increases) and meridional circulation (arrows)
in CISK (a) and WISHE (b) theories for hurricane development. (a) Frictionally induced
boundary layer convergence moistens the environment and destabilizes it through layer
ascent. This enables small-scale plumes to reach their levels of free convection easily and to
produce cumulonimbus clouds. Diabatic heating due to the resulting precipitation drives the
large-scale circulation and thus maintains the large-scale convergence. (b) The saturation
θ
e
is tied to the θ
e
of the boundary layer. The warm core occurs because enhanced surface
fluxes of latent heat increase θ
e
there. (After Emanuel, 2000.)
