Operational detection of contrails from NOAA-AVHRR-data

This paper describes a fully automated scheme that allows for the detection of contrails using the infrared channels of the Advanced Very High Resolut ion Radiometer (AVHRR). The presented algorithm is adjusted to have a low r ate of misdetection in spite of the low contrail detection efficiency resul ting from this tuning. A time-series and regional patterns of contrail clou diness over Central and Western Europe are derived. Daily analysis of noon scenes in 1996 indicates that the average of daytime contrail coverage over Central Europe was 0.5% +/- 0.25 with regional maxima of 1.2%. Comparing n oon and midnight scenes shows that night-time contrail coverage, which is e specially effective in greenhouse forcing, is approximately one-third of th at of daytime.