Chapter 4 - Hot Towers
Published online by Cambridge University Press: 05 June 2012
Summary
The graphic term “hot tower” has originated with Riehl and Malkus (1958), to describe their conceptual model intended to explain the peculiar distribution of “total static energy” or “moist static energy,” cpT + gz + Lvq, that they found in the tropical atmosphere (Figure 4.1). Between the energy-rich mixed layer below, and the equally energetic air high in the troposphere, a considerable energy deficit is evident, greatest just above the Trade Inversion. They realized that the high values of total static energy aloft cannot be the result of simple area-wide mixing or advection from below, especially if radiant cooling is taken into account. As Johnson (1969) points out in his review, Riehl and Malkus (1958) proposed that “the ascent [of low level air].… took place in the embedded central cores of cumulonimbus clouds, protected from mixing with the environment by the large cross-section of the clouds.” Release of latent heat turns the central cores of cumulonimbus into hot towers and generates fast ascent in them. In spite of their “large” individual cross section, their aggregate area is small, compared to the area of the global tropical ocean. Mass balance dictates that the total upward mass transport in all the hot towers return to low levels. This takes place in slow subsidence outside hot towers (i.e., over most of the tropical ocean). Hot towers form the upward leg of an overturning atmospheric circulation.
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- Air-Sea InteractionLaws and Mechanisms, pp. 146 - 186Publisher: Cambridge University PressPrint publication year: 2001