The formula to calculate the lapse rate is:
\[ L = \frac{g}{C_p} \]
Where:
A lapse rate is defined as the rate at which an atmospheric variable such as temperature changes with a change in altitude.
A lapse rate occurs because as a change in altitude occurs, a change in air density occurs. The less-dense air causes changes in pressure and temperature. The change in pressure is caused by the effect of gravity acting on the air.
Let's consider an example:
Using the formula to calculate the lapse rate:
\[ L = \frac{9.81}{1005} \approx 0.0098 \text{ °C/km} \]
This demonstrates that with a specific heat capacity of 1005 J/kg·K, the lapse rate is approximately 0.0098 °C/km. ✅