Final answer:
The letter 'q' in the equation represents heat or thermal energy in the context of the given equation. It is a general representation of heat, representing heat transfer in various forms such as sensible heat, latent heat, and heat flux.
Step-by-step explanation:
The letter 'q' in the equation represents heat or thermal energy in the context of the given equation.
In the equation Q = QG + QH + QLE, QG represents the sensible heat flux or the heat transfer through conduction, QH represents the latent heat flux or the heat transfer associated with phase change (evaporation/condensation), and QLE represents the latent heat flux or the heat transfer associated with evaporation and condensation.
Therefore, 'q' is a general representation of heat in the given equation, representing heat transfer in various forms such as sensible heat, latent heat, and heat flux.