Reconsider the flow illustrated in Figure P7.22. Suppose that you have conclusive evidence that the water temperature at the surface of the lower body of water is slightly lower than that at the...

Reconsider the flow illustrated in Figure P7.22. Suppose that you have conclusive evidence that the water temperature at the surface of the lower body of water is slightly lower than that at the surface of the upper body of water. Offer a viable explanation for this observation.