A regional Bowen ratio is computed from an aerological energy budget approach with both mean monthly and a daily upper air and surface data for Northern Canada. Elsasser radiation computations are made from the mean soundings, the net heat added (or lost) in the column is computed, evaporation is estimated from the change in the precipitable water during the motion along the trajectory, and, finally the Bowen ratio and the complete heat budget are evaluated from the "climatological" soundings and trajectories according to the residual equation, L0=Rn-S-E0