Contrail Reduction Strategies Using Different Weather Resources

Two weather products used extensively in aviation are the wind, temperature and hu-midity forecast as part of the Rapid Update Cycle and the weather forecast provided by the Corridor Integrated Weather System. These weather forecasts have been used to es-timate traffic delays and to design aircraft routes avoiding severe weather. The Rapid Update Cycle forecast has been used to strategically plan reductions of aircraft induced contrails. Currently, concepts for weather avoidance and contrail reduction are separate. This paper uses these two weather forecasts in a complementary way to develop contrail reduction strategies in the presence of different weather conditions. The concept of contrail frequency index is used to quantify the severity of contrail formation and is modified with additional weather information. The contrail frequency index is defined as the number of aircraft flying through regions that would form contrails during a period of time. When the weather forecast indicates that there were already clouds in the regions, the index is dis-counted. The index is used to identify the air traffic control centers and altitudes with high potential for contrail formation in the next few hours. This is so that different strategies can be used to reduce the contrail formation in the entire airspace by altering the aircraft cruising altitudes. When severe weather is present, the feasibility of the strategies will be evaluated. For the day tested, contrail frequency index was discounted by 14 % when taking into account the effect of cloud coverage. The contrail reduction strategy achieves a 63.7 % contrail reduction taking into account the weather impact if the aircraft are allowed to alter their cruising altitude by 2,000 feet, and a 92.6 % reduction if by 4,000 feet. The proposed contrail reduction strategies are suitable for reducing contrail formation in the entire airspace with the presence of different weather conditions. I