Define and compare dry adiabatic rates and moist adiabatic rates

Answer 1

An adiabatic process is when a parcel of air expands and cools, or compresses and warms, with no interchange of heat with its outside surroundings. If the air in the parcel is unsaturated (the relative humidity is less than 100%), the rate of adiabatic cooling or warming remains constant. This rate of cooling or warming only applies to unsaturated air, so it is called the dry adiabatic rate. As the rising air cools, its relative humidity increases as the air temperature approaches the dew-point temperature. If the rising air cools to its dew-point temperature, the relative humidity becomes 100%. Further lifting results in condensation, a cloud forms, and latent heat is released in the rising air. The air no longer cools at the dry adiabatic rate but a lesser rate called the moist adiabatic rate. The rate at which rising or sinking saturated air changes temperature - the moist adiabatic rate - is less than the dry adiabatic rate. Furthermore, unlike the dry adiabatic rate, the moist adiabatic rate is not constant, but varies greatly with temperature.