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Dry Adiabatic Lapse Rate Equation:
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The Dry Adiabatic Lapse Rate (DALR) is the rate at which the temperature of a parcel of dry air decreases as it rises in the atmosphere without exchanging heat with its surroundings. It is a fundamental concept in atmospheric science and meteorology.
The calculator uses the Dry Adiabatic Lapse Rate equation:
Where:
Explanation: The equation represents the temperature change per unit altitude for a dry air parcel rising or descending adiabatically in the atmosphere.
Details: Understanding the dry adiabatic lapse rate is crucial for predicting atmospheric stability, cloud formation, and weather patterns. It helps meteorologists determine whether air parcels will continue to rise (unstable atmosphere) or resist vertical movement (stable atmosphere).
Tips: Enter gravitational acceleration in m/s² (Earth's standard is 9.8 m/s²) and specific heat capacity in J/kg·K (standard value for dry air is approximately 1005 J/kg·K). All values must be positive numbers.
Q1: What is the typical value of DALR on Earth?
A: The standard dry adiabatic lapse rate on Earth is approximately 9.8 K/km, calculated using g = 9.8 m/s² and Cp = 1005 J/kg·K.
Q2: How does DALR differ from the moist adiabatic lapse rate?
A: The moist adiabatic lapse rate is lower than DALR because latent heat release during condensation partially offsets the cooling of rising air.
Q3: Why is DALR important in aviation?
A: Pilots use knowledge of lapse rates to anticipate turbulence, cloud formation, and temperature changes at different altitudes.
Q4: Does DALR vary on other planets?
A: Yes, the dry adiabatic lapse rate varies on other planets depending on their gravitational acceleration and atmospheric composition.
Q5: How does altitude affect the calculation?
A: While g decreases slightly with altitude, the change is negligible for most practical applications in the lower atmosphere.