[Understanding Weather & Climate, Books a la Carte Edition (6th Edition) #ISBN-13: 978-0321773227 #ISBN-10: 0321773225 CH 5 Atmospheric Moisture]
Diabatic /Adiabatic process
Diabatic process (e.g formation of fog)
– is involving adding OR removing energy from a system.
Adiabatic process (e.g formation of clouds)
– is involving temperature changes but no heat is added or removed from a substance – i.e ∆H = 0
(REF: [ ∆H (change in heat) = P∆V + c∆T ])
In terms of cloud’s formation –
Expanding air cools; Compressing air warms:
– base on adiabatic process AND 1st law of thermodynamic
Volume of gas increasing (V↑) + Internal energy decreasing (Temp↓) ⇒ no change in heat
[formula: Positive work + (negative temperature) ⇒ ∆H = 0]
In the atmosphere, air raise, encounter lower surrounding pressure, it expands and cools.