Postulate a parcel of air within the larger atmosphere. The air above the parcel is cooler than the parcel, while the air below it is warmer. The parcel is emitting photons to both the overlying and the underlying layers of air and simultaneously absorbing photons from both layers. Both sets of photons that are absorbed by the parcel help to warm the parcel. My understanding of the thermodynamic definition of heat is that absorbed photons from the lower warmer layer represent heat; while the absorbed photons from the upper cooler layer merely represent thermal energy. Am I correct in this understanding, or am I missing something?