Density of a dry-adiabatically lifted air parcel
For dry adiabatic ascent, T2 = T1*(P2/P1)^(R/cp), with R/cp ~ 0.286. Here T1 = 30C = 303.15 K, P1=1000 hPa, P2=500 hPa: T2 = 303.15*(0.5)^0.286...
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