MOIST vs DRY ADIABATIC RATES

Lapse rates imply warming and cooling of air. Moist, or saturated adiabatic lapse rate, and the dry adiabatic lapse rate are the two types of lapse rates.

The dry adiabatic lapse rate is simply unsaturated. The term dry implies to parcels of air without water content. For every hundred meters, there is one degree Celsius of cooling. The higher the altitude, the lower is the pressure. Thus, when a parcel of air rises to 200 meters, it will gain 2 degree Celsius of cooling. And when it descends, the normal temperature of that parcel of air will be regained. As the air rises, it cools, and when it cools it will definitely meet its dew point. The dry adiabatic lapse rate actual temperature is definitely higher than the dew point. With this, condensation can take place and the clouds will be formed. Thus, clouds are formed when there is condensation of parcel of air reaching its dew point.

Saturated, or moist, adiabatic lapse rate are parcels of air that are already moist. Thus, when it arises, it will become colder and expands. This has a saturated lapse rate of 0.5 ˚C per 100 meters. Unlike the dry adiabatic lapse rate, this parcel of air rises slowly due to the fact that it already contains water which makes it heavy and as it rises, it loses its internal heat. This plunge in temperature is caused by the decrease in pressure of the atmosphere as the altitude becomes high. Therefore the parcel of air in moist adiabatic lapse rate expands as it goes higher. During expansion, the parcels of air are working, but without involving heat loss. This type of lapse rate cools the clouds.

Basically, the saturated adiabatic lapse rate is less compared to the dry adiabatic lapse rate. This is because the cooling of the parcel of air in the saturated adiabatic lapse rate during rising is divided into energy released upon condensation. The energy/ heat released during saturated adiabatic lapse rate come from its internal and not based on the external temperature. Moist adiabatic lapse rate varies with temperatures. This is determined by the quantity of water vapor that squeezes or condenses. When cool parcel of air rises up, the dry air inside the clouds rises and condensation of water vapor is less, therefore the saturated adiabatic lapse rate in this situation is larger. When more water vapor is condensing, the saturated adiabatic lapse rate becomes lesser. If the dry adiabatic lapse rate forms the clouds, the moist adiabatic lapse rate on the other hand is responsible for the thunderstorms, and the like.

The term adiabatic refers to the unchanging external heat. Meaning, the term implies that no heat is loss or gained. The heat of the parcel of air is stable and does not change with the outside environment. Lapse rate refers to the change in rates as the parcel of air rises and lowers. Therefore, the change in rates varies with the height and not merely implies the rate change.

Summary:

1.Lapse rates imply warming and cooling of air. Moist, or saturated adiabatic lapse rate, and the dry adiabatic lapse rate are the two types of lapse rates.

2.The term adiabatic refers to the unchanging external heat. Meaning, the term implies that no heat is loss or gained. The heat of the parcel of air is stable and does not change with the outside environment.

3.The dry adiabatic lapse rate is simply unsaturated. For every hundred meters, there is one degree Celsius of cooling. The higher the altitude, the lower is the pressure. . And when it descends, the normal temperature of that parcel of air will be regained. As the air rises, it cools, and when it cools it will definitely meet its dew point. The dry adiabatic lapse rate actual temperature is definitely higher than the dew point.

4.Thus, clouds are formed when there is condensation of parcel of air reaching its dew point.

5.Saturated, or moist, adiabatic lapse rate are parcels of air that are already moist. Thus, when it arises, it will become colder and expands. This has a saturated lapse rate of 0.5 ˚C per 100 meters. Unlike the dry adiabatic lapse rate, this parcel of air rises slowly due to the fact that it already contains water which makes it heavy and as it rises, it loses its internal heat.

6.The energy/ heat released during saturated adiabatic lapse rate come from its internal and not based on the external temperature.

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