ABSTRACT
When the sun is shining, for instance, the ground may become too hot to walk on barefoot, as on a dry, sunny beach in midsummer. At the ground surface the temperature may exceed 65° C, while at head height it may be only 30° C, and in the shade, where most temperature observations are made, it may be as low as 20° C. Similar variations can be found in wind speed and humidity. So, we may ask, what is it about this layer near the ground which produces such major gradients – gradients that are not repeated anywhere in the free atmosphere?
