Near-surface coherent structures explored by large eddy simulation of entire tropical cyclones

Ito, Junshi; Oizumi, Tsutao; Niino, Hiroshi

doi:10.1038/s41598-017-03848-w

Cited by 32 publications

(40 citation statements)

References 41 publications

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“…Rotunno et al (2009) and Green and Zhang (2015) suggest that the horizontal resolution should be below 100 m to simulate the development of 3-D turbulent eddies in the TCBL. Ito et al (2017) found that the near-surface coherent structures can be successfully simulated by using the horizontal resolution of 70 m, which appears to be caused by an inflectionpoint instability of both radial and tangential winds.…”

Section: Introductionmentioning

confidence: 98%

Tornado-scale vortices in the tropical cyclone boundary layer: numerical simulation with the WRF–LES framework

2019

Atmos. Chem. Phys.

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Abstract. A tornado-scale vortex in the tropical cyclone (TC) boundary layer (TCBL) has been observed in intense hurricanes and the associated intense turbulence poses a severe threat to the manned research aircraft when it penetrates hurricane eyewalls at a lower altitude. In this study, a numerical experiment in which a TC evolves in a large-scale background over the western North Pacific is conducted using the Advanced Weather Research and Forecast (WRF) model by incorporating the large-eddy simulation (LES) technique. The simulated tornado-scale vortex shows features similar to those revealed with limited observational data, including the updraft–downdraft couplet, the sudden jump of wind speeds, the location along the inner edge of the eyewall, and the small horizontal scale. It is suggested that the WRF–LES framework can successfully simulate the tornado-scale vortex with grids at a resolution of 37 m that cover the TC eye and eyewall. The simulated tornado-scale vortex is a cyclonic circulation with a small horizontal scale of ∼1 km in the TCBL. It is accompanied by strong updrafts (more than 15 m s−1) and large vertical components of relative vorticity (larger than 0.2 s−1). The tornado-scale vortex favorably occurs at the inner edge of the enhanced eyewall convection or rainband within the saturated, high-θe layer, mostly below an altitude of 2 km. In nearly all the simulated tornado-scale vortices, the narrow intense updraft is coupled with the relatively broad downdraft, constituting one or two updraft–downdraft couplets, as observed by the research aircraft. The presence of the tornado-scale vortex also leads to significant gradients in the near-surface wind speed and wind gusts.

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Section: Introductionmentioning

confidence: 98%

Tornado-scale vortices in the tropical cyclone boundary layer: numerical simulation with the WRF–LES framework

2019

Atmos. Chem. Phys.

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“…Rolls do occur in boundary layers beyond hurricanes; in fact, rolls were originally associated with airmass cloud bands [4][5][6][7]. Furthermore, rolls with different characteristics and driving mechanisms have since been identified and classified [8,9], with multiple types of rolls also identified and classified for hurricanes [10][11][12][13][14][15]. Large eddy simulations have been used to characterize rolls at finer granularity in recent years [16][17][18], and most recently, rolls have even been observed to be associated with high wind bands in extratropical cyclones [19].…”

Section: Introductionmentioning

confidence: 99%

Large Roll Vortices Exhibited by Post-Tropical Cyclone Sandy during Landfall

Schiavone¹,

Gao

Robinson

et al. 2021

Atmosphere

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Roll vortices are frequent features of a hurricane’s boundary layer, with kilometer or sub-kilometer horizontal scale. In this study, we found that large roll vortices with O (10 km) horizontal wavelength occurred over land in Post-Tropical Cyclone Sandy (2012) during landfall on New Jersey. Various characteristics of roll vortices were corroborated by analyses of Doppler radar observations, a 500 m resolution Weather Research and Forecasting (WRF) simulation, and an idealized roll vortex model. The roll vortices were always linear-shaped, and their wavelengths of 5–14 km were generally larger than any previously published for a tropical cyclone over land. Based on surface wind observations and simulated WRF surface wind fields, we found that roll vortices significantly increased the probability of hazardous winds and likely caused the observed patchiness of treefall during Sandy’s landfall.

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“…Such a combination of resolutions in the nesting (e.g., Muñoz-Esparza et al, 2018), allows us to avoid "gray zone" or "Terra Incognita" problems for which turbulence parameterization is difficult (Wyngaard, 2004). The remaining model settings are similar to our previous studies using JMA-NHM (e.g., Ito et al, 2017).…”

Section: Numerical Simulationsmentioning

confidence: 99%

Large Eddy Simulation on Horizontal Convective Rolls that Caused an Aircraft Accident during its Landing at Narita Airport

Ito

Niino

Yoshino³

2020

Geophysical Research Letters

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An accident occurred when an aircraft landed at Narita International Airport, Japan, on 20 June 2012. The aircraft encountered rapid changes of winds together with strong turbulence, although the weather was fair. In the present study, a two‐domain nested regional weather prediction models are used. The results in the outer domain show that southwesterly winds associated with a synoptic extratropical cyclone were locally accelerated to the southwest of the airport resulting in strong vertical shear. The simulation in the inner domain reproduces horizontal convective rolls, which are similar to those observed by a Doppler lidar at the airport. The wind velocity component parallel to the runway had a spatial variation of about 10 m s −1. The present approach using a large eddy simulation is useful for clarifying environments and features of horizontal convective rolls and forecasting low‐level wind shear associated with them, which can be a significant risk for aircraft.

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Near-surface coherent structures explored by large eddy simulation of entire tropical cyclones

Cited by 32 publications

References 41 publications

Tornado-scale vortices in the tropical cyclone boundary layer: numerical simulation with the WRF–LES framework

Tornado-scale vortices in the tropical cyclone boundary layer: numerical simulation with the WRF–LES framework

Large Roll Vortices Exhibited by Post-Tropical Cyclone Sandy during Landfall

Large Eddy Simulation on Horizontal Convective Rolls that Caused an Aircraft Accident during its Landing at Narita Airport

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