National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000, USA
Received: 06 Mar 2013 – Discussion started: 24 Apr 2013
Abstract. A comprehensive general circulation model including ice supersaturation is used to estimate the climate impact of aviation induced contrails. The model uses a realistic aviation emissions inventory for 2006 to initiate contrails, and allows them to evolve consistently with the model hydrologic cycle.
Revised: 31 Oct 2013 – Accepted: 11 Nov 2013 – Published: 20 Dec 2013
The radiative forcing from linear contrails is very sensitive to the diurnal cycle. For linear contrails, including the diurnal cycle of air traffic reduces the estimated radiative forcing by 29%, and for contrail cirrus estimates, the radiative forcing is reduced by 25%. Estimated global radiative forcing from linear contrails is 0.0031 ± 0.0005 Wm−2. The linear contrail radiative forcing is found to exhibit a strong diurnal cycle. The contrail cirrus radiative forcing is less sensitive to the diurnal cycle of flights. The estimated global radiative forcing from contrail cirrus is 0.013 ± 0.01 Wm−2. Over regions with the highest air traffic, the regional effect can be as large as 1 Wm−2.
Chen, C.-C. and Gettelman, A.: Simulated radiative forcing from contrails and contrail cirrus, Atmos. Chem. Phys., 13, 12525-12536, doi:10.5194/acp-13-12525-2013, 2013.