Question

Note in passing: We will consider that a parcel that is saturated (contains cloud droplets) will warm at the moist adiabatic rate (here, 5°C) when it sinks, until the cloud droplets evaporate. Continued descent will then produce warming at the dry adiabatic rate. This process is called a reversible moist adiabatic process.

6. Suppose we have a cloudy parcel at a temperature of 10°C at 1km height. The parcel sinks to cloud base at 800 m height and then continues to sink to sea level. What will it's temperature be at sea level?
7. What is the typical tropospheric lapse rate, as given in the Standard Atmosphere?
8. Compare the standard atmosphere's typical value of lapse rate with the dry adiabatic lapse rate. Would you say that the atmosphere is typically stable or unstable?

Answer 1

1.

The temperature at sea level considering sea level as 0 m the temperature of cloud parcel will be 16 ' C . as per the point no D

as per the rule

A. as long as the parcel is unsaturated the rate of cooling is 10 ' C for every 1000 m height parcel is lifted.

B. a rising parcel cools its relative humidity increases once the relative humidity reaches 100% further lifting results in net condensation forming a cloud.

C. when lowering an air parcel in the atmosphere the temperature changes are reversed if there is no cloud ( liquid water) in parcel the air temperature in parcel increases at a rate of 10'C for every 1000 m parcel is lowered .

D if there is cloud in parcel enough water will evaporate to keep the relative humidity at 100 % and the dew point ( saturated) temperature equal to the air atmosphere . since it takes energy to evaporate the rate off heating is slower . cloud warms at a rate of 6 ' C for every 1000 m the parcel is lowered untill the entire cloud has evaporated

2. lapse rate is defined as the change in temperature when moving upward from earth atmosphere.

the typical tropospheric lapse rate rate is 6.5 ' C per kilometer rise

( additional information

dry adibatic lapse rate is 9.8 ' C per kilometer rise )

3

Adiabatic lapse rate is defined as rate at which the temperature of an air parcel changes in response to compression or expansion associated with elevation change ( assumption no heat exchange occurs between the given air parcel and its surrounding)

a unstable atmosphere is one that encourages continual vertical motion of air either upward or downwards.

the environmental lapse rate is less than the dry adiabatic lapse rate so there is turbulence in the atmosphere and is said to to be unstable (  Super -adiabatic)