(a) What are the main factors that determine the wind distribution in the PBL? (b) On a summer day that is clear with no frontal activity over land, sketch typical virtual potential temperature and water vapor mixing ratio profiles in the early afternoon and in the midnight. (c) Explain why in going up and down a high mountain, air temperature can increase substantially at the downwind base compared to that at the upwind base. (d) Under what conditions is the static stability parameter not likely to be a reliable indicator of the stability of the layer? Give an example.