Understanding Aircraft Contrail Radiative forcing Using Satellite observations

Abstract:

Air traffic can induce a substantial climate impact through the formation of contrail cirrus from jet engine emissions. The contrails are normally high in altitude, optically thin in shortwave bands, but efficient at trapping longwave radiation on its way to space via the greenhouse effect. Recent studies estimated that the global mean radiative forcing from contrails is about 11.3 mW m^-2. Regionally, the radiative forcing can be as large as 0.5 W m^-2, such as over the east coast of the U.S. and Western Europe. However, the contrail parameterization in those models is very simple. For an accurate contrail radiative forcing assessment, it is important to better constrain the contrail optical properties using spaceborne observations. In this study, we detect the contrails using Machine Learning techniques applied to the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) observations. After contrail detection is complete, we retrieve the optical properties of contrails and use them as constraints in a global climate model.