Net Mass Transport Research Articles

The white box: The mean mechanics of the cumulus cycle

AbstractA region surrounding a cumulus cloud is defined in such a way that (when virtual temperature effects are neglected) there is no sensible heat transfer across the boundaries of the region. This simplifies the discussion of the interaction between the cumulus and its environment. A model of the region, which is called the white box, is developed and an estimate is made of the net vertical mass transport within it as a function of height. Rain and cloud radiation have the effect of modifying this transport and may be described in terms of it. If the requirements of continuity are satisfied by means of an alteration of the wind profile of the environment downstream, the wind near the base of the cloud downstream is increased. It is shown that cumulus convection can destabilize as well as stabilize its environment.

Spring-warming transfer processes in the lower antarctic stratosphere

Earlier evaluations of heat balance requirements in the lower stratosphere from sounding data had resulted in excessive radiational net-cooling rates (budget residuals) during 1958 and 1960 spring warming periods, viz. 4° to 6°C/day. The imbalance arises chiefly from stratospheric subsidence rates calculated with the assumption of vanishing net mass transport across the top of the highest datum layer (75 and 25 mb level respectively). When vertical mass transport is assumed to vanish relative to a minimum temperature surface (stratobase) which descends on to the principal Antarctic tropopause, quasi-Lagrangian radiational cooling rates of 0.5 to 1.5°C/day obtain in 1960 and 1964 stratospheric warming periods. The hypothesis of an impermeable stratobase requires transient ascent at the 25 mb level suggesting a temporarily reversed meridional circulation overlying the direct polar cell. The associated vertical divergence in the lower stratosphere is examined for its effects on ozone changes in this layer and observed changes of total ozone at Halley Bay, Mirny and Dumont d'Urville. DOI: 10.1111/j.2153-3490.1967.tb01470.x

Spring-warming transfer processes in the lower antarctic stratosphere

Earlier evaluations of heat balance requirements in the lower stratosphere from sounding data had resulted in excessive radiational net-cooling rates (budget residuals) during 1958 and 1960 spring warming periods, viz. 4° to 6°C/day. The imbalance arises chiefly from stratospheric subsidence rates calculated with the assumption of vanishing net mass transport across the top of the highest datum layer (75 and 25 mb level respectively). When vertical mass transport is assumed to vanish relative to a minimum temperature surface (stratobase) which descends on to the principal Antarctic tropopause, quasi-Lagrangian radiational cooling rates of 0.5 to 1.5°C/day obtain in 1960 and 1964 stratospheric warming periods. The hypothesis of an impermeable stratobase requires transient ascent at the 25 mb level suggesting a temporarily reversed meridional circulation overlying the direct polar cell. The associated vertical divergence in the lower stratosphere is examined for its effects on ozone changes in this layer and observed changes of total ozone at Halley Bay, Mirny and Dumont d'Urville. DOI: 10.1111/j.2153-3490.1967.tb01470.x