MET-question concerning pressure levels
Hey guys,
this is my first thread here and I hope there's someone that could help me with my problem. There's a question in the MET-exams, which answer I can't understand:
Q: "Flying from Marseilles (QNH 1012) to Palma (QNH 1015) at FL100. You don't reset the altimeter, why would the true altitude be the same throughout the flight?"
A: "Air at Marseilles is warmer than air at Palma"
I can't figure out, why that's the correct answer... Can someone help me please?