Estimation of Eddy Dissipation Rates from Mesoscale Model Simulations

Ahmad, Nashat N.; Proctor, Fred H.

doi:10.2514/6.2012-429

Cited by 8 publications

(7 citation statements)

References 28 publications

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“…However, in stably stratified environments it can be used as a scaling factor for other indices (Sharman and Pearson 2017;Muñoz-Esparza and Sharman 2018). EDR is a common turbulence diagnostic that is physically based and in past studies has predicted turbulence in the midlatitudes accurately (Ahmad and Proctor 2012;Barber et al 2018). However, in this oceanic study EDR underpredicted turbulence.…”

Section: Discussionmentioning

confidence: 75%

Properties of Convectively Induced Turbulence over Developing Oceanic Convection

Barber

Deierling

Mullendore

et al. 2019

Monthly Weather Review

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Convectively induced turbulence (CIT) is an aviation hazard that continues to be a forecasting challenge as operational forecast models are too coarse to resolve turbulence affecting aircraft. In particular, little is known about tropical maritime CIT. In this study, a numerical simulation of a tropical oceanic CIT case where severe turbulence was encountered by a commercial aircraft is performed. The Richardson number (Ri), subgrid-scale eddy dissipation rate (EDR), and second-order structure functions (SF) are used as diagnostics to determine which may be used for CIT related to developing and mature convection. Model-derived subgrid-scale EDR in past studies of midlatitude continental CIT was shown to be a good diagnostic of turbulence but underpredicted turbulence intensity and areal coverage in this tropical simulation. SF diagnosed turbulence with moderate to severe intensity near convection and agreed most with observations. Further, SF were used to diagnose turbulence for developing convection. Results show that the areal coverage of turbulence associated with developing convection is less than mature convection. However, the intensity of turbulence in the vicinity of developing convection is greater than the turbulence intensity in the vicinity of mature convection highlighting developing convection as an additional concern to aviation.

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Section: Discussionmentioning

confidence: 75%

Properties of Convectively Induced Turbulence over Developing Oceanic Convection

Barber

Deierling

Mullendore

et al. 2019

Monthly Weather Review

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“…EDR is a popular aviation turbulence metric that is not dependent on physical aircraft variables such as type, weight, and speed (Poellot and Grainger 1991;Emanuel et al 2013). EDR can be calculated using various inflight data such as vertical acceleration, true airspeed, and three-dimensional winds (Poellot and Grainger 1991;Cornman et al 1995;Emanuel et al 2013;Ahmad and Proctor 2012). The calculation for EDR used in this study is and D02) -…”

Section: Eddy Dissipation Ratementioning

confidence: 99%

Section: Eddy Dissipation Ratementioning

confidence: 99%

“…where TKE is the turbulent kinetic energy (m 2 s 22 ) and L is a length scale (Ahmad and Proctor 2012). Ahmad and Proctor (2012) investigated the accuracy of boundary layer turbulence intensity when using a length scale L that is dependent on the model PBL scheme. Their study concluded that EDR at 40 m above ground level (AGL) when calculated using a model-predicted L was less accurate than a constant L of 336 m. Other constant length scales were evaluated but also found to be less accurate.…”

Section: Eddy Dissipation Ratementioning

confidence: 99%

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Out-of-Cloud Convective Turbulence: Estimation Method and Impacts of Model Resolution

Barber

Mullendore

Alexander

2018

Journal of Applied Meteorology and Climatology

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Convectively induced turbulence (CIT) poses both a serious threat to aviation operations and a challenge to forecasting applications. CIT generation and propagation processes occur on scales between 10 and 1000 m and therefore are best treated with high-resolution cloud-resolving models. However, high-resolution model simulations are computationally expensive, limiting their operational use. In this study, summertime convection in the North Dakota region is simulated over a 1-week period using a variety of model setups that are similar to those utilized in operational and research applications. Eddy dissipation rate and Ellrod index, both popular turbulence metrics, are evaluated across various model resolutions and compared with pilot reports from aircraft. The Ellrod index was found to be extremely sensitive to model resolution and overestimated turbulence intensity. The variability of turbulence values with respect to model resolution and distance away from convection is also examined. Turbulence probability was found to be the greatest when farther than 20 mi (32.2 km) away from convective cores. Model resolution was found to influence the intensity of predicted turbulence, and the model setup with the highest horizontal and vertical resolution predicted the highest turbulence values. However, the influence on turbulence intensity of vertical resolution and convective properties, such as storm depth, was found to be minimal for 3-km horizontal grid spacing.

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“…Ahmad and Proctor 15 have previously described the use of WRF model outputs of TKE and the master length scale which are used to compute the EDR in a post-processing step. A similar methodology was used here for application to the Denver Airport.…”

Section: Mesoscale Modelingmentioning

confidence: 99%

Atmospheric Turbulence Estimates from a Pulsed Lidar

Pruis

Delisi

Ahmad

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Estimation of Eddy Dissipation Rates from Mesoscale Model Simulations

Abstract: The Eddy Dissipation Rate is an important metric for representing the intensity of atmospheric turbulence and is used as an input parameter for predicting the decay of aircraft wake vortices. In this study, the forecasts of eddy dissipation rates obtained from

Cited by 8 publications

References 28 publications

Properties of Convectively Induced Turbulence over Developing Oceanic Convection

Properties of Convectively Induced Turbulence over Developing Oceanic Convection

Out-of-Cloud Convective Turbulence: Estimation Method and Impacts of Model Resolution

Atmospheric Turbulence Estimates from a Pulsed Lidar

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