2. Cloud base altitude: We can estimate the cloud base altitude from the properties of surface air. Consider an air parcel at the Earth's surface with temperature of 20C and relative humidity (Ph20/ Ph20,54T) of 30%. As this air parcel rises in the atmosphere it cools following the adiabatic lapse rate. We would like to determine the altitude at which it will form a cloud. Use the following equation for the saturation vapor pressure of water PH2O,SAT (hPa) as a 17.67 TC function of temperature tc (C): PH205ur = 6.1 * exp (1,7:23.5 Tc+ a) If pho remains constant in the rising air parcel, calculate the altitude of cloud base. b) In fact, pho decreases in the rising air parcel because of the decrease in atmospheric pressure. Assuming an atmospheric scale height H = 7.4 km, determine the altitude of the cloud base