DRY ADIABATIC LAPSE RATE Meaning and
Definition
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The dry adiabatic lapse rate refers to the rate at which the temperature of a dry parcel of air changes as it ascends or descends in the atmosphere without exchanging heat with its surroundings. It is commonly denoted as DALR.
In a dry adiabatic process, the rising or sinking air parcel experiences changes solely due to the expansion or compression caused by changes in atmospheric pressure. As the parcel ascends, the pressure decreases and so does the surrounding air pressure against it. Consequently, the air parcel expands, leading to a cooling effect. Conversely, as the parcel descends, the surrounding air pressure increases, causing the parcel to compress and warm up.
The dry adiabatic lapse rate is considered to be approximately 9.8 degrees Celsius per kilometer of altitude. This rate is constant and independent of the initial parcel temperature. However, it is important to note that the actual lapse rate in the atmosphere may deviate from this standard value due to various factors, including the presence of moisture, clouds, or other phenomena.
By understanding the dry adiabatic lapse rate, meteorologists can make predictions about atmospheric stability, cloud formation, and the potential for convection. It serves as a fundamental concept in atmospheric sciences, allowing for the analysis of how temperature changes affect the behavior of air masses at different altitudes.
