Contrail Layer Forecasts for Fairbanks, Alaska

The condensation trail (contrail) layers for the subarctic setting of Fairbanks have been analyzed and forecasted based on atmospheric sounding measurements and vertical profiles derived from the MM5 mesoscale atmospheric circulation model. An operational contrail observation site was established in 2001 for verification. Using an improved Schmidt-Appleman criterion the contrail formation was confirmed for the majority of our observations. Without taking into account different aircraft types we derived a success-rate of 0.91 for the near real-time contrail analysis when using an average aircraft specific contrail factor of 0.0365 g/kg K. Forecasts of contrail layers could be involved in flight planning in order to avoid contrail formation and corresponding possible climatic effects. High correlation was found for the comparison of the 6 hour (r ∼ 0.94) and 30 hour (r ∼ 0.88) forecasts of contrail layer boundaries with the boundaries derived from atmospheric sounding for the period from February until July 2003.