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.
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.
Turbulence (clear-air, mountain wave, convectively induced) is an aviation hazard that is a challenge to forecast due to the coarse resolution ultilized in operational weather models. Turbulence indices are commonly used to aid pilots in avoiding turbulence, but these indices have been designed and calibrated for midlatitude clear-air turbulence prediction (e.g., the Ellrod Index. A significant limitation with current convectively induced turbulence (CIT) prediction is the lack of storm stage dependency. In this study, six high-resolution simulations of tropical oceanic and midlatitude continental convection are performed to characterize the turbulent environment near various convective types during the developing and mature stages. Second-order structure functions, a diagnostic commonly used to identify turbulence in turbulence prediction systems, are used to characterize the probability of turbulence for various convective types. Turbulence likelihood was found to be independent of region (i.e., tropical versus midlatitude) but dependent on convective stage. The probability of turbulence increased near developing convection for the majority of cases. Additional analysis of static stability and vertical wind shear, indicators of turbulence potential, showed that the convective environment near developing convection was more favorable for turbulence production than mature convection. Near developing convection, static stability decreased and vertical wind shear increased. Vertical wind shear near mature and developing convection was found to be weakly correlated to turbulence intensity in both the tropics and midlatitudes. This study emphasizes the need for turbulence avoidance guidelines for the aviation community that are dependent on convective stage.
At its simplest, paint pouring is the mixing of paints with lower density and viscosity liquids and then pouring them onto a surface for an aesthetic artifact. Using active art as a teaching tool, middle school students were engaged in a paint pouring activity to study the influence of the interdisciplinary combination of chemistry and art topics on student understanding of density, viscosity, and creativity. It is accepted that hands-on activities increase the understanding of complex topics because students are able to apply these topics to real-world applications. Survey analysis (N = 124) of a pre- and post-event survey with 14 Likert scale questions broken into the following categories: density, science and creativity, viscosity, and art. The pre- and post-surveys included three multiple-choice questions indicating that student’s understanding of the importance of density and viscosity in art increased after completing the activity. Of the 14 Likert scale questions, 11 showed an increased self-reported understanding of the scientific concepts and enthusiasm for art after engaging in the paint pouring exercise. Three responses did not increase, as the students already wanted to complete a paint pour and recognized paint pouring as an art activity. It was also observed that, after completing the exercise, students were receptive to how science and art can be integrated. Correct student responses to the multiple choice all increased in the post-survey, providing evidence for the self-reported increased student understanding of density and viscosity.
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