On optical and microphysical characteristics of contrails and cirrus

Febvre, Guy; Gayet, Jean-François; Minikin, Andreas; Schläger, Hans; Shcherbakov, Valéry; Jourdan, Olivier; Busen, R.; Fiebig, Markus; Kärcher, B.; Schumann, U.

doi:10.1029/2008jd010184

Cited by 59 publications

(121 citation statements)

References 61 publications

(78 reference statements)

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“…CoCiP is applied to compute the ice bulk properties of contrails for comparison with in-situ measurements for various contrail ages (5 s-2000 s) behind various aircraft as reported by Schröder et al (2000), Febvre et al (2009) and for the CONCERT campaign (Voigt et al, 2010). (We do not expect good agreement for CoCiP for the youngest contrails.)…”

Section: Young and Mid-aged Contrails In Comparison With In-situ Obsementioning

confidence: 99%

“…the value consistent with the reported ice water content IWC and volume mean diameter d mean ; both values, partly with large differences, are listed in Table 4. The measured concentrations are uncertain due to variable lower cut-off size of ice particles in the data analysis (Febvre et al, 2009). Some aircraft types and humidity values were unknown and had to be estimated.…”

Section: Young and Mid-aged Contrails In Comparison With In-situ Obsementioning

confidence: 99%

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A contrail cirrus prediction model

2012

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Abstract.A new model to simulate and predict the properties of a large ensemble of contrails as a function of given air traffic and meteorology is described. The model is designed for approximate prediction of contrail cirrus cover and analysis of contrail climate impact, e.g. within aviation system optimization processes. The model simulates the full contrail life-cycle. Contrail segments form between waypoints of individual aircraft tracks in sufficiently cold and humid air masses. The initial contrail properties depend on the aircraft. The advection and evolution of the contrails is followed with a Lagrangian Gaussian plume model. Mixing and bulk cloud processes are treated quasi analytically or with an effective numerical scheme. Contrails disappear when the bulk ice content is sublimating or precipitating. The model has been implemented in a "Contrail Cirrus Prediction Tool" (CoCiP). This paper describes the model assumptions, the equations for individual contrails, and the analysis-method for contrailcirrus cover derived from the optical depth of the ensemble of contrails and background cirrus. The model has been applied for a case study and compared to the results of other models and in-situ contrail measurements. The simple model reproduces a considerable part of observed contrail properties. Mid-aged contrails provide the largest contributions to the product of optical depth and contrail width, important for climate impact.

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Section: Young and Mid-aged Contrails In Comparison With In-situ Obsementioning

confidence: 99%

Section: Young and Mid-aged Contrails In Comparison With In-situ Obsementioning

confidence: 99%

A contrail cirrus prediction model

2012

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“…Allowing the atmosphere and surface below the layer to be reflective with an effective albedo A, we apply a two-stream approach leading to (Twomey, 1977), with the cloud reflectance r= βτ µ 1 1+βτ/µ (Coakley and Chylek, 1975), the upscattered fraction of incident sunlight, β, the SW cloud optical depth, τ , and µ= cos θ . According to aircraft observations (Febvre et al, 2009) (Liou et al, 1990), since contrails do not act as perfect black bodies. The contrail layer reduces the outgoing LW flux in proportion to E,…”

Section: Radiative Transfer Parametrizationmentioning

confidence: 99%

Effects of optical depth variability on contrail radiative forcing

Kärcher

Burkhardt

2012

Quart J Royal Meteoro Soc

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Line-shaped contrails arising from aircraft emissions affect radiative forcing. The magnitude of the radiative forcing from contrails depends strongly on their optical depth and their spatial and temporal variability caused by dynamical and microphysical processes. Here we investigate the significance of this variability, both for modelling contrail radiative forcing and estimating thresholds for the detection of contrails in satellite imagery. Ignoring the variability of contrail optical depth in models by prescribing a mean optical depth may overestimate mean net radiative forcing by 10−20%. Undersampling of optically thin line-shaped contrails by passive satellite remote sensing is linked to the inability to detect flux changes in the outgoing long-wave radiation below ≈ 3 W m −2 for conditions over the eastern North Pacific. Consideration of these findings aids efforts to better quantify uncertainties in aviation climate assessments.

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“…Ice crystals in young contrails are considerably smaller than the ones that form in natural cirrus clouds and occur with sub-25 stantially higher ice crystal number concentrations (Febvre et al, 2009;Schröder et al, 2000;Voigt et al, 2010). Therefore, the original microphysical scheme was extended by a new hydrometeor class that allows for a separate treatment of the small contrail ice crystals separate from natural ice.…”

mentioning

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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On optical and microphysical characteristics of contrails and cirrus

Cited by 59 publications

References 61 publications

A contrail cirrus prediction model

A contrail cirrus prediction model

Effects of optical depth variability on contrail radiative forcing

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

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