Thermodynamic diagram and upper air information

Adiabatic processes on a thermodynamic chart.

• Adiabatic process
• dq/dt = 0 (no work done)!!
• Thus, the internal energy equals the pressure work term. Also, now there are no diabatics so;

Adiabatic processes on a thermodynamic chart.

• Expansion (lower pressure) cooling  work done on air parcel and energy lost to environment
• Contraction (higher pressure) warming  work done by environment and energy gained at expense of environment

Adiabatic processes on a thermodynamic chart.

• Constant Potential Temperature  Adiabatic system or flow follows lines of potential temperature.
• Why? Let’s derive relationship for potential temperature

Adiabatic processes on a thermodynamic chart.

• Derive…..start with 1st law

Adiabatic processes on a thermodynamic chart.

• And….