ACPD paper on contrail observations

Hazel Jones has submitted a detailed study of COSIC contrail observations

Satellite image from Flight B587

Forecast models were utilised to determine flight regions suitable for contrail formation and sampling; regions that were both free of cloud but showed a high probability of occurrence of air mass being supersaturated with respect to ice. The FAAM research aircraft, fitted with cloud microphysics probes and remote sensing instruments, formed a distinctive spiral-shaped contrail in the predicted area by flying in an orbit over the same ground position as the wind advected the contrails to the east. Parts of these contrails were sampled during the completion of four orbits, with sampled contrail regions being between 7 and 30 min old. Lidar measurements were useful for in-flight determination of the location and spatial extent of the contrails, and also to report extinction values that agreed well with those calculated from the microphysical data. A shortwave spectrometer was also able to detect the contrails, though the signal was weak due to the dispersion and evaporation of the contrails. Post-flight the UK Met Office NAME III dispersion model was successfully used as a tool for modelling the dispersion of the persistent contrail; determining its location and age, and determining when there was interference from other measured other aircraft contrails or when cirrus encroached on the area later in the flight.

The persistent contrails were found to consist of small (~10 ?m) plate-like crystals where growth of ice crystals to larger sizes (~100 ?m) was detected when higher water vapour levels were present. Using the cloud microphysics data, extinction co-efficient values were calculated and found to be 0.01–1 km?1. The contrails formed during the flight (referred to as B587) were found to have a visible lifetime of ~40 min, and limited water vapour supply was thought to have suppressed ice crystal growth.

Annual linear contrail coverage

Jones, H. M., Haywood, J., Marenco, F., O’Sullivan, D., Meyer, J., Thorpe, R., Gallagher, M. W., Krämer, M., Bower, K. N., Rädel, G., Rap, A., Forster, P., and Coe, H.: A methodology for in-situ and remote sensing of microphysical and radiative properties of contrails as they evolve into cirrus, Atmos. Chem. Phys. Discuss., 12, 7829-7877, doi:10.5194/acpd-12-7829-2012, 2012.

Spracklen DV; Jimenez JL; Carslaw KS; Worsnop DR; Evans MJ; Mann GW; Zhang Q; Canagaratna MR; Allan J; Coe H; McFiggans G; Rap A; Forster P (2011) Aerosol mass spectrometer constraint on the global secondary organic aerosol budget ATMOSPHERIC CHEMISTRY AND PHYSICS11, pp.12109-12136. doi:10.5194/acp-11-12109-2011

Spracklen DV; Carslaw KS; Poeschl U; Rap A; Forster PM (2011) Global cloud condensation nuclei influenced by carbonaceous combustion aerosol ATMOSPHERIC CHEMISTRY AND PHYSICS11, pp.9067-9087. doi:10.5194/acp-11-9067-2011

Fueglistaler S; Haynes PH; Forster PM (2011) The annual cycle in lower stratospheric temperatures revisited ATMOSPHERIC CHEMISTRY AND PHYSICS11, pp.3701-3711. doi:10.5194/acp-11-3701-2011

Kurten T; Zhou L; Makkonen R; Merikanto J; Raisanen P; Boy M; Richards N; Rap A; Smolander S; Sogachev A; Guenther A; Mann GW; Carslaw K; Kulmala M (2011) Large methane releases lead to strong aerosol forcing and reduced cloudiness ATMOSPHERIC CHEMISTRY AND PHYSICS11, pp.6961-6969. doi:10.5194/acp-11-6961-2011

Rädel G, Shine KP (2010) Validating ECMWF forecasts for the occurrence of ice supersaturation using visual observations of persistent contrails and radiosonde measurements over England Q.J.R.Meteorol.Soc 136:1723-1732 doi: 10.1002/qj.670

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Heymsfield, A; Baumgardner, D; DeMott, P; Forster, P; Gierens, K; Karcher, B (2010) CONTRAIL MICROPHYSICS, B AM METEOROL SOC91, pp.465-+. doi:10.1175/2009BAMS2839.1

Rap, A; Forster, PM; Jones, A; Boucher, O; Haywood, JM; Bellouin, N; De Leon, RR (2010) Parameterization of contrails in the UK Met Office Climate Model, J GEOPHYS RES-ATMOS115, . doi:10.1029/2009JD012443

Rap, A; Forster, PM; Haywood, JM; Jones, A; Boucher, O (2010) Estimating the climate impact of linear contrails using the UK Met Office climate model, GEOPHYS RES LETT37, . doi:10.1029/2010GL045161

Haywood, JM; Allan, RP; Bornemann, J; Forster, PM; Francis, PN; Milton, S; Radel, G; Rap, A; Shine, KP; Thorpe, R (2009) A case study of the radiative forcing of persistent contrails evolving into contrail-induced cirrus, J GEOPHYS RES-ATMOS114, . doi:10.1029/2009JD012650

Myhre, G; Kvalevag, M; Radel, G; Cook, J; Shine, KP; Clark, H; Karcher, F; Markowicz, K; Kardas, A; Wolkenberg, P; Balkanski, Y; Ponater, M; Forster, P; Rap, A; de Leon, RR (2009) Intercomparison of radiative forcing calculations of stratospheric water vapour and contrails, METEOROL Z18, pp.585-596. doi:10.1127/0941-2948/2009/0411