Stratospheric Wave Spectra Resembling Turbulence

Dewan, E. M.

doi:10.1126/science.204.4395.832

Cited by 173 publications

(126 citation statements)

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“…The state of turbulence in this region is highly anisotropic and often composed of largescale horizontal quasi 2d motions with little vertical motions. These motions are composed of wavy motions and intermittent turbulent spots (Dewan, 1979;Dörnbrack and Dürbeck, 1998;Riley and Lindborg, 2008). The kinetic energy spectrum follows a −3-power law for the large scales and a −5/3-power law for smaller scales, suggesting either 2d turbulence or 3d inertial range turbulence, but local isotropy requires smaller scales (Nastrom and Gage, 1985;Riley and Lindborg, 2008).…”

Section: The Turbulence 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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Section: The Turbulence Modelmentioning

confidence: 99%

A contrail cirrus prediction model

2012

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“…These fluctuations are believed to be superpositions of various atmospheric gravity waves with different wave lengths (e.g. Dewan, 1979;VanZandt, 1982). Spectral analysis is adopted to express gravity wave characteristics.…”

Section: Vertical Wave Number Spectrummentioning

confidence: 99%

Analysis of vertical wave number spectrum of atmospheric gravity waves in the stratosphere using COSMIC GPS radio occultation data

et al. 2011

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Abstract. GPS radio occultation (RO) is characterized by high accuracy and excellent height resolution, which has great advantages in analyzing atmospheric structures including small-scale vertical fluctuations. The vertical resolution of the geometrical optics (GO) method in the stratosphere is about 1.5 km due to Fresnel radius limitations, but full spectrum inversion (FSI) can provide superior resolutions. We applied FSI to COSMIC GPS-RO profiles from ground level up to 30 km altitude, although basic retrieval at UCAR/CDAAC sets the sewing height from GO to FSI below the tropopause. We validated FSI temperature profiles with routine high-resolution radiosonde data in Malaysia and North America collected within 400 km and about 30 min of the GPS RO events. The average discrepancy at 10-30 km altitude was less than 0.5 K, and the bias was equivalent with the GO results.Using the FSI results, we analyzed the vertical wave number spectrum of normalized temperature fluctuations in the stratosphere at 20-30 km altitude, which exhibits good consistency with the model spectra of saturated gravity waves. We investigated the white noise floor that tends to appear at high wave numbers, and the substantial vertical resolution of the FSI method was estimated as about 100-200 m in the lower stratosphere. We also examined a criterion for the upper limit of the FSI profiles, beyond which bending angle perturbations due to system noises, etc., could exceed atmospheric excess phase fluctuations. We found that the FSI profiles can be used up to about 28 km in studies of temperature fluctuations with vertical wave lengths as short as 0.5 km.

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“…First we shall follow Clifford11 (pp. [37][38][39] and consider the following two questions: "What is the optimum hize of an eddy, In relation to the wavelength of radiation, for causing fading effects ?" and "How does the weighting effect, x 5/6, arise in Eq.…”

Section: Fddies a Lenses (An Addendum)mentioning

confidence: 99%

Optical Turbulence Forecasting: A Tutorial

Dewan¹

1980

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Stratospheric Wave Spectra Resembling Turbulence

Cited by 173 publications

References 12 publications

A contrail cirrus prediction model

A contrail cirrus prediction model

Analysis of vertical wave number spectrum of atmospheric gravity waves in the stratosphere using COSMIC GPS radio occultation data

Optical Turbulence Forecasting: A Tutorial

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