Difference between revisions of "Reversible moist-adiabatic process"

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<div class="definition"><div class="short_definition">A [[moist-adiabatic process]] in which the air is maintained at  [[saturation]] by the [[evaporation]] or [[condensation]] of water substance, the [[enthalpy]] of [[water vapor]]  formed or removed being supplied by or to the air, respectively.</div><br/> <div class="paragraph">In contrast to a [[pseudoadiabatic expansion]], the liquid water that condenses in an [[air parcel]]  expanding through a reversible moist-adiabatic process is carried with the parcel, so that subsequent  compression occurs with moist-[[adiabatic]] warming, leading to the original state. This can only  happen if the condensed water drops are small enough to have negligible fallout velocities. The  [[moist-adiabatic lapse rate]] for the [[reversible process]] is given by  <div class="display-formula"><blockquote>[[File:ams2001glos-Re37.gif|link=|center|ams2001glos-Re37]]</blockquote></div> where &#x00393;<sub>''rm''</sub> is the reversible moist-adiabatic lapse rate; ''g'' is [[gravity]]; ''r''<sub>''v''</sub>, ''r''<sub>''l''</sub>, and ''r''<sub>''t''</sub> are the [[mixing]] of  water vapor, liquid water, and total water; ''c''<sub>''pd''</sub>, ''c''<sub>''pv''</sub>, and ''c'' are the [[specific heats]] at constant [[pressure]]  of [[dry air]], water vapor, and liquid water; ''L''<sub>''v''</sub> is the [[heat of vaporization]]; ''R'' is the dry air gas  constant; &#x003b5; is the ratio of the [[gas constants]] of dry air and water vapor (&asymp; 0.622); and ''T'' is  [[temperature]].</div><br/> </div>
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<div class="definition"><div class="short_definition">A [[moist-adiabatic process]] in which the air is maintained at  [[saturation]] by the [[evaporation]] or [[condensation]] of water substance, the [[enthalpy]] of [[water vapor]]  formed or removed being supplied by or to the air, respectively.</div><br/> <div class="paragraph">In contrast to a [[pseudoadiabatic expansion]], the liquid water that condenses in an [[air parcel]]  expanding through a reversible moist-adiabatic process is carried with the parcel, so that subsequent  compression occurs with moist-[[adiabatic]] warming, leading to the original state. This can only  happen if the condensed water drops are small enough to have negligible fallout velocities. The  [[moist-adiabatic lapse rate]] for the [[reversible process]] is given by  <div class="display-formula"><blockquote>[[File:ams2001glos-Re37.gif|link=|center|ams2001glos-Re37]]</blockquote></div> where &#x00393;<sub>''rm''</sub> is the reversible moist-adiabatic lapse rate; ''g'' is [[gravity]]; ''r''<sub>''v''</sub>, ''r''<sub>''l''</sub>, and ''r''<sub>''t''</sub> are the [[mixing ratio|mixing]] of  water vapor, liquid water, and total water; ''c''<sub>''pd''</sub>, ''c''<sub>''pv''</sub>, and ''c'' are the [[specific heats]] at constant [[pressure]]  of [[dry air]], water vapor, and liquid water; ''L''<sub>''v''</sub> is the [[heat of vaporization]]; ''R'' is the dry air gas  constant; &#x003b5; is the ratio of the [[gas constants]] of dry air and water vapor (&asymp; 0.622); and ''T'' is  [[temperature]].</div><br/> </div>
 
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Latest revision as of 17:47, 25 April 2012



reversible moist-adiabatic process

A moist-adiabatic process in which the air is maintained at saturation by the evaporation or condensation of water substance, the enthalpy of water vapor formed or removed being supplied by or to the air, respectively.

In contrast to a pseudoadiabatic expansion, the liquid water that condenses in an air parcel expanding through a reversible moist-adiabatic process is carried with the parcel, so that subsequent compression occurs with moist-adiabatic warming, leading to the original state. This can only happen if the condensed water drops are small enough to have negligible fallout velocities. The moist-adiabatic lapse rate for the reversible process is given by
ams2001glos-Re37
where Γrm is the reversible moist-adiabatic lapse rate; g is gravity; rv, rl, and rt are the mixing of water vapor, liquid water, and total water; cpd, cpv, and c are the specific heats at constant pressure of dry air, water vapor, and liquid water; Lv is the heat of vaporization; R is the dry air gas constant; ε is the ratio of the gas constants of dry air and water vapor (≈ 0.622); and T is temperature.