Global survey of jet contrails using AVHRR data: spatial distributions and optical property retrievals

Jet contrails are considered to be a subset of thin cirrus clouds. Due to their semitransparent nature, thin cirrus are thought to be enhancers of the greenhouse effect. They are almost transparent to the incoming solar energy reaching the surface, and also they reduce the planetary emissions to space due to their cold temperatures. Jet contrails are considered responsible not so much for increases of cloudiness, but rather to enhance the formation of natural cloudiness. In the present study, one month of daytime global Advanced Very High Resolution Radiometer (AVHIR) data are used to 1) automatically detect contrails, 2) estimate the global frequency of occurrence of contrails, and 3) estimate the optical depth and particle size of jet contrails. One month (April, 1993) of daily AVHRR LAC (Local Area Coverage) satellite data on board the NOAA-11 satellite is used in this investigation