Composite ship track characteristics

The physical and radiative properties of a composite ship track are describ ed from the analysis of 131 ship-ship track correlation pairs collected dur ing the Monterey Area Ship Track experiment. The significant variability uf ship tracks around their average characteristics is also described. The no minal environmental conditions for the ship track set are also described. T he composite ship track is 296 +/- 233 km long, 7.3 +/- 6 h old, and averag es 9 +/- 5 km wide. The ship is, on the average, 16 +/- 8 km from of the he ad of the ship track along the relative wind vector and corresponds to a ti me of 2.5 +/- 15 min. The set of ship tracks examined in this study formed in marine boundary layers that were between 300 and 750 m deep, and no trac ks formed in boundary layers above 800 m. The tracks form in regions of hig h relative humidity: small air-sea temperature differences, and moderate wi nds (average of 7.7 +/- 3.1 m s(-1)). The ambient cloud reflectance in adva nced very high resolution radiometer channel 3 (3.7-mu m wavelength) is 11 +/- 4%, while the composite ship track Value is 14 +/- 5%. The relative tra ck brightness is 7 +/- 26% and 37 +/- 34% for 0.63- and 3.7-mu m wavelength s, respectively.