Wednesday, 25 January 2012: 9:45 AM
An Overview of a Northern Hemisphere Contrail Climatology Derived From MODIS Measurements
Room 257 (New Orleans Convention Center )
Estimates of the radiative impact of contrails on climate vary by at least an order of magnitude. As air traffic increases worldwide, contrail coverage is expected to increase also, and more accurate estimates of contrail coverage are needed to reduce this uncertainty. Nearly all estimates of global radiative forcing from line-shaped contrails use estimates of regional contrail coverage derived from satellite imagery. Although several studies of regional contrail coverage are available, no comprehensive study of line-shaped contrail coverage over the Northern Hemisphere has been produced. We use an automated contrail detection algorithm (CDA) to determine the coverage of line-shaped persistent contrails over the Northern Hemisphere throughout 2006. The contrail detection algorithm is a modification of the Mannstein et al. (1999) method, and uses several channels from the Terra and Aqua MODerate-resolution Imaging Spectroradiometers (MODIS) to reduce the occurrence of false positive detections. In addition, we will discuss methods to improve the reliability of the contrail coverage detection through comparisons with flight track data. Estimates of contrail properties including optical depth, longwave radiative forcing and contrail height will also be presented. Future work will focus on extending this near-global contrail climatology to 2008 or 2010.