Use of the Atmospheric Infrared Sounder (AIRS) Surface Skin and Air Temperature Data Over Rural and Urban-Industrial Regions in Canada and the USA

We investigate the changes in surface air and skin temperatures for the period 2003 to 2007 over southern Ontario, Canada and bordering US States, as well as two urban-industrial and one rural sub-region. Surface air and skin temperatures acquired by the Atmospheric Infrared Sounder (AIRS) were used. The data indicate an overall increase in all temperatures for all areas, over the period. Both minimum and maximum temperatures are increasing, but minimum temperatures appear to be increasing at a faster rate in rural areas. There is also an indication that nighttime skin temperature is increasing faster than nighttime air temperature, so that there is a convergence of these two temperatures. In the urban areas, the daytime air temperature is increase marginally faster than the daytime skin temperature. This is contrary to the pattern in the rural areas, and is indicative of the effect of human activity on air temperature during the daytime. The data also indicate that during periods of daytime temperature inversions, the air temperature is warmer than the skin temperature, in both urban and rural areas.