Vortex bursting and tracer transport of a counter-rotating vortex pair

Misaka, Takashi; Holzäpfel, Frank; Hennemann, Ingo; Gerz, Thomas; Manhart, Michael; Schwertfirm, Florian

doi:10.1063/1.3684990

Cited by 71 publications

(116 citation statements)

References 55 publications

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“…For weak ambient shear, the width of the contrail B is of order (π/2) s, where s is the span width of the aircraft (in agreement with Misaka et al (2012); see below). The effective (in the sense of representing the optically effective depth of an ellipsoidal contrail cross section; see Schumann, 2012) contrail depth H and effective contrail width B are related to the contrail cross-section area by A = BH .…”

Section: The Cocip Modelsupporting

confidence: 51%

“…The derived contrail depths of about 110 to 290 m for the various aircraft is comparable to the depth of 110 m deduced from ground-based lidar observations by Sassen and Hsueh (1998) for a 2 min-old contrail of a DC8 aircraft (mass about 100 Mg). In order to scale optical contrail properties to unit flight distance, we integrate the extinction over the vertical ellipsoidal contrail cross section (for results see Table 6), whereby the contrail depth is derived from the P2P model (Holzäpfel, 2006) and the contrail width from Misaka et al (2012) (their Fig. 23).…”

Section: Impact Of Fuel Flow On Contrail Optical Propertiesmentioning

confidence: 99%

“…Ice crystal number densities and sizes can vary in the primary vortices and the secondary wake (Gayet et al, 2012). After the breakup of the vortex structures, initiated from small disturbances by the Crow instability or from ambient turbulence (Misaka et al, 2012), the contrail spreads out and disperses depending on atmospheric wind shear and turbulence (Jensen et al, 1998). Contrails may survive for several hours in ice supersaturated conditions (Graf et al, 2012), with the total contrail cover being dependent on air traffic movement and distribution.…”

Section: Introductionmentioning

confidence: 99%

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Aircraft type influence on contrail properties

et al. 2013

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Abstract. The investigation of the impact of aircraft parameters on contrail properties helps to better understand the climate impact from aviation. Yet, in observations, it is a challenge to separate aircraft and meteorological influences on contrail formation. During the CONCERT campaign in November 2008, contrails from 3 Airbus passenger aircraft of types A319-111, A340-311 and A380-841 were probed at cruise under similar meteorological conditions with in situ instruments on board DLR research aircraft Falcon. Within the 2 min-old contrails detected near ice saturation, we find similar effective diameters D eff (5.2-5.9 µm), but differences in particle number densities n ice (162-235 cm −3 ) and in vertical contrail extensions (120-290 m), resulting in large differences in contrail optical depths τ at 550 nm (0.25-0.94). Hence larger aircraft produce optically thicker contrails.Based on the observations, we apply the EULAG-LCM model with explicit ice microphysics and, in addition, the Contrail and Cirrus Prediction (CoCiP) model to calculate the aircraft type impact on young contrails under identical meteorological conditions. The observed increase in τ for heavier aircraft is confirmed by the models, yet for generally smaller τ . CoCiP model results suggest that the aircraft dependence of climate-relevant contrail properties persists during contrail lifetime, adding importance to aircraftdependent model initialization. We finally derive an analytical relationship between contrail, aircraft and meteorological parameters. Near ice saturation, contrail width × τ scales linearly with the fuel flow rate, as confirmed by observations. For higher relative humidity with respect to ice (RHI), the analytical relationship suggests a non-linear increase in the form (RHI-1) 2/3 . Summarized, our combined results could help to more accurately assess the climate impact from aviation using an aircraft-dependent contrail parameterization.

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Section: The Cocip Modelsupporting

confidence: 51%

Section: Impact Of Fuel Flow On Contrail Optical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aircraft type influence on contrail properties

et al. 2013

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“…Three-dimensional (3d) large eddy simulation (LES) models resolve the fluid dynamics of wake vortex formation and decay (Gerz and Ehret, 1996;Lewellen and Lewellen, 1996;Holzäpfel et al, 2010;Misaka et al, 2012) and the bulk microphysics of contrails (Gierens, 1996;Chlond, 1998;Lewellen and Lewellen, 2001;Unterstrasser and Sölch, 2010;Naiman et al, 2011), but require large computing times. Even two-dimensional (2d) variants of such models, which allow for parameter studies and several hours of contrail ages, are too expensive to be applied for simulations of a large ensemble of contrails with realistic meteorological variability (Jensen et al, 1998a;Gierens and Jensen, 1998;Unterstrasser and Gierens, 2010b).…”

Section: U Schumann: Contrail Cirrus Modelmentioning

confidence: 99%

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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“…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%

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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Vortex bursting and tracer transport of a counter-rotating vortex pair

Cited by 71 publications

References 55 publications

Aircraft type influence on contrail properties

Aircraft type influence on contrail properties

A contrail cirrus prediction model

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

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