A comparison of rooftop and surface temperature observations

For many years the primary temperature observations taken for weather and climate were taken in federal networks. A relatively small number of the observations have been taken on rooftops at National Weather Service sites. In recent years a much larger number of temperature observations have been initiated in many networks with a wider variety of instrumentation. In this new era of non-federal data collection there has been a growth in the number of rooftop observation sites. The concurrent expansion of electronic communications has allowed these observations to be immediately available to a wide audience of users including the public, private companies, school students, the media and the government.

This presentation will report on a comparison of rooftop and surface temperatures. The primary emphasis in this presentation is to explore physical causes for differences between rooftop and surface observations using the surface radiating temperatures in the vicinity of the rooftop and surface air temperature observations. Results will be shown from observations taken in Colorado, Wyoming and the Virginia-Maryland area. Results indicate the minimum temperatures are usually quite close to nearby radiating temperatures while maximum temperatures can be considerably cooler than surface radiating temperatures in the convective boundary layer.