A contrail cirrus prediction model

Schumann, U.

doi:10.5194/gmd-5-543-2012

Cited by 151 publications

(263 citation statements)

References 154 publications

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“…Contrails may have a climate impact similar in magnitude to the radiative forcing from aircraft CO 2 emissions (Lee et al, 2009(Lee et al, , 2010Burkhardt and Kärcher, 2011;Schumann et al, 2012). Still the uncertainties of this estimate are large (Heymsfield et al, 2010;Burkhardt et al, 2010;Toohey et al, 2010).…”

Section: Introductionmentioning

confidence: 94%

“…The primary vortices descend downwards until the rotational vortex motion gets unstable, turbulent and dissipates. The maximum sinking distance depends on ambient stratification, shear, and turbulence and on aircraft properties (Lewellen and Lewellen, 2001;Sussmann and Gierens, 2001;Holzäpfel, 2003;Unterstrasser, 2008;Misaka et al, 2012;Schumann 2012). Ice crystals form early in the jet phase within some tenths of a second.…”

Section: Introductionmentioning

confidence: 99%

“…Poellot et al (1999) and Schröder et al (2000) measured contrails in the dispersion regime between 3 min and 1 h contrail age. These data were also used for comparison to contrail models (Unterstrasser and Gierens, 2010;Naiman et al, 2011;Schumann, 2012). The measurements and model results show that mean ice particle concentrations decrease and mean ice particle diameters increase in ice supersaturated air masses with contrail age.…”

Section: Introductionmentioning

confidence: 99%

“…Measuring ice crystal concentration, size, shape and extinction of contrails in the vortex phase is crucial for the initialization and validation of contrail models, since it determines contrail evolution (Lewellen and Lewellen, 2001;Unterstrasser et al, 2008;Unterstrasser and Gierens, 2010;Paugam et al, 2010;Naiman et al, 2011;Schumann, 2012). In addition, improving our understanding on microphysical and optical properties of young contrails may help to reduce the uncertainties in contrail radiative forcing Schumann et al, 2011a).…”

Section: Introductionmentioning

confidence: 99%

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The evolution of microphysical and optical properties of an A380 contrail in the vortex phase

et al. 2012

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Abstract.A contrail from a large-body A380 aircraft at cruise in the humid upper troposphere has been probed with in-situ instruments onboard the DLR research aircraft Falcon. The contrail was sampled during 700 s measurement time at contrail ages of about 1-4 min. The contrail was in the vortex regime during which the primary wake vortices were sinking 270 m below the A380 flight level while the secondary wake remained above. Contrail properties were sampled separately in the primary wake at 90 and 115 s contrail age and nearly continously in the secondary wake at contrail ages from 70 s to 220 s. The scattering phase functions of the contrail particles were measured with a polar nephelometer. The asymmetry parameter derived from these data is used to distinguish between quasi-spherical and aspherical ice particles. In the primary wake, quasi-spherical ice particles were found with concentrations up to 160 cm −3 , mean effective diameter D eff of 3.7 µm, maximum extinction of 7.0 km −1 , and ice water content (IWC) of 3 mg m −3 at slightly ice-subsaturated conditions. The secondary and primary wakes were separated by an almost particle-free wake vortex gap. The secondary wake contained clearly aspherical contrail ice particles with mean D eff of 4.8 µm, mean (maximum) concentration, extinction, and IWC of 80 (350) cm −3 , 1.6 (5.0) km −1 , and 2.5 (10) mg m −3 , respectively, at conditions apparently above ice-saturation. The asymmetry parameter in the secondary wake decreased with contrail age from 0.87 to 0.80 on average indicating a preferential aspherical ice crystal growth. A retrieval of ice particle habit and size with an inversion code shows that the number fraction of aspherical ice crystals increased from 2 % initially to 56 % at 4 min contrail age. The observed crystal size and habit differences in the primary and secondary wakes of an up to 4 min old contrail are of interest for understanding ice crystal growth in contrails and their climate impact. Aspherical contrail ice particles cause less radiative forcing than spherical ones.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The evolution of microphysical and optical properties of an A380 contrail in the vortex phase

et al. 2012

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“…1 Large-Eddy Simulation 2 Reynolds-Averaged Navier Stokes Regarding the contrail microphysics and the interaction with the meteorological situation, the entire procedure is online coupled, thus allowing feedback processes between contrails and natural clouds in contrast to other models on a comparable grid scale (Schumann, 2012). One of the key goals of this study is thus to quantify the influence of contrails and contrail cirrus on natural high-level cloudiness.…”

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confidence: 99%

Contrails and Their Impact on Shortwave Radiation and Photovoltaic Power Production – A Regional Model Study

Gruber¹,

Unterstraßer²,

Bechtold³

et al. 2017

Preprint

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Abstract. A high resolution regional-scale numerical model was extended by a parameterization that allows for both the generation and the life cycle of contrails and contrail cirrus to be calculated. The life cycle of contrails and contrail cirrus is described by a two-moment cloud microphysical scheme that was extended by a separate contrail ice class for a better representation of the high concentration of small ice crystals that occur in contrails. The basic input data set contains the spatially and temporally highly resolved flight trajectories over Central Europe derived from real time data. The parameterization provides 5 aircraft-dependent source terms for contrail ice mass and number. A case study was performed to investigate the influence of contrails and contrail cirrus on the radiative fluxes at the earth's surface. Accounting for contrails produced by aircraft enabled the model to simulate high clouds that were otherwise missing on this day. The effect of these extra clouds was to reduce the incoming shortwave radiation at the surface as well as the production of photovoltaic power by up to 10 %.

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A Lagrangian analysis of ice‐supersaturated air over the North Atlantic

2014

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[1] Understanding the nature of air parcels that exhibit ice supersaturation is important because they are the regions of potential formation of both cirrus and aircraft contrails, which affect the radiation balance. Ice-supersaturated air parcels in the upper troposphere and lower stratosphere over the North Atlantic are investigated using Lagrangian trajectories. The trajectory calculations use European Centre for Medium-Range Weather Forecasts Interim reanalysis data for three winter and three summer seasons, resulting in approximately 200,000 trajectories with ice supersaturation for each season. For both summer and winter, the median duration of ice supersaturation along a trajectory is less than 6 h. Five percent of air which becomes ice supersaturated in the troposphere and 23% of air which becomes ice supersaturated in the stratosphere will remain ice supersaturated for at least 24 h. Weighting the ice-supersaturation duration with the observed frequency indicates the likely overall importance of the longer duration ice-supersaturated trajectories. Ice-supersaturated air parcels typically experience a decrease in moisture content while ice supersaturated, suggesting that cirrus clouds eventually form in the majority of such air. A comparison is made between short-lived (less than 24 h) and long-lived (greater than 24 h) ice-supersaturated air flows. For both air flows, ice supersaturation occurs around the northernmost part of the trajectory. Short-lived ice-supersaturated air flows show no significant differences in speed or direction of movement to subsaturated air parcels. However, long-lived ice-supersaturated air occurs in slower-moving air flows, which implies that they are not associated with the fastest moving air through a jet stream.Citation: Irvine, E. A., B. J. Hoskins, and K. P. Shine (2014), A Lagrangian analysis of ice-supersaturated air over the North Atlantic,

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A contrail cirrus prediction model

Cited by 151 publications

References 154 publications

The evolution of microphysical and optical properties of an A380 contrail in the vortex phase

The evolution of microphysical and optical properties of an A380 contrail in the vortex phase

Contrails and Their Impact on Shortwave Radiation and Photovoltaic Power Production – A Regional Model Study

A Lagrangian analysis of ice‐supersaturated air over the North Atlantic

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