Hydraulic and Wave Aspects of Novorossiysk Bora

Шестакова, А. А.; Moiseenko, K. B.; Toropov, P. A.

doi:10.1007/978-3-030-11958-4_3

Cited by 3 publications

(3 citation statements)

References 39 publications

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“…(), figure 6 of Kusaka and Fudeyasu () and figure 3a of Shestakova et al . (). Since the values of the Richardson number at the critical level

R i_{c} = N_{0}^{2} / α^{2}

to be adopted are never lower than 0.5 except in one case, the reflectivity due to atmospheric profile features aloft should generally not exceed about 3% (Teixeira et al ., , Figure 4), which means that this part of the profile is irrelevant for the present calculations, as in Teixeira et al .…”

Section: Theory and Linear Numerical Modelmentioning

confidence: 97%

The dependence of mountain wave reflection on the abruptness of atmospheric profile variations

Teixeira

Argaín

2020

Quart J Royal Meteoro Soc

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It is known from geometric optics that a change in refractive index is potentially reflective if it occurs over scales much smaller than the wavelength of the incident waves. The limitations of this assumption for hydrostatic orographic gravity waves are tested here using linear theory and a method recently developed by the authors to evaluate the reflection coefficient, based on the wave drag. Two atmospheric profiles optimally suited to this method are adopted, the first with piecewise constant static stability (representative of a tropopause), and the second with constant wind speed near the surface, and a linearly decreasing wind aloft below a critical level (relevant to downslope windstorms). Both profiles consist of two atmospheric layers separated by a transition layer with controllable thickness, where the parameters vary continuously. The variation of the reflection coefficient between its maximum (for a zero‐thickness transition layer) and zero, as the ratio of the thickness of the transition layer to the vertical wavelength increases, is studied systematically. The reflection coefficient attains half of its maximum for a value of this ratio of about 0.3, but its exact variation depends on the jump in static stability between the two layers in the first profile, and the Richardson number at the critical level in the second. For a stronger contrast between the two layers, the reflection coefficient is larger, but also decays to zero faster for thinner transition layers. According to these results, most atmospheric profile features perceived as discontinuities are likely to have close‐to‐maximum reflection coefficients, and the variation of atmospheric parameters over a sizeable fraction of the troposphere can still lead to significant wave reflection. These results seem to hold quantitatively to a good degree of approximation in moderately nonlinear flow for the first atmospheric profile, but only qualitatively for the second one.

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“…(), figure 6 of Kusaka and Fudeyasu () and figure 3a of Shestakova et al . (). Since the values of the Richardson number at the critical level

R i_{c} = N_{0}^{2} / α^{2}

Section: Theory and Linear Numerical Modelmentioning

confidence: 97%

The dependence of mountain wave reflection on the abruptness of atmospheric profile variations

Teixeira

Argaín

2020

Quart J Royal Meteoro Soc

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“…The occurrence of downslope windstorms are usually accompanied with hydraulic jumps, partial reflection, and critical‐level reflection, according to various numerical and theoretical studies in the past few decades (Afanasyev & Peltier, 1998; Cao & Fovell, 2016; Durran, 1990; Epifanio & Qian, 2008; Houghton & Kasahara, 1968; Klemp & Lilly, 1975; Long, 1953; Rögnvaldsson et al., 2011; Smith, 1985). The combination of hydraulic jumps and wave breaking can also enhance downslope windstorms and increase the wind speed (Shestakova et al., 2018; Tollinger et al., 2019). The pressure gradient force (PGF) is one of the possible factors that accelerates the wind speed near the exit of the gap between the mountains when prevailing winds blow into a narrow valley with appropriate directions (Colle & Mass, 2000; Finnigan et al., 1994; Reed, 1931; Yamada & Hirasawa, 2018).…”

Section: Introductionmentioning

confidence: 99%

Orographic‐Induced Strong Wind Associated With a Low‐Pressure System Under Clear‐Air Condition During ICE‐POP 2018

et al. 2022

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A strong wind event under clear‐air conditions during the 2018 Winter Olympic and Paralympic games in Pyeongchang, Korea, was examined using various datasets. High spatiotemporal resolution wind information was obtained by Doppler lidars, automatic weather stations, wind profiler, sounding observations, reanalysis datasets under the International Collaborative Experiments for Pyeongchang 2018 Olympic and Paralympic winter games (ICE‐POP 2018). This study aimed to understand the possible mechanisms of localized strong winds across a high mountainous area and on the leeside associated with the underlying large‐scale pattern of a low‐pressure system (LPS). The evolution of surface winds shows quite different patterns, exhibiting intensification of strong winds in the leeside and periodically persistent strong winds in upstream mountainous areas with the approaching LPS. The surface wind speed was intensified from ∼3 to ∼12 m s−1 (gusts were stronger than 20 m s−1 above the ground) at a surface station in the leeside. A budget analysis of the horizontal momentum equation suggested that the pressure gradient force (PGF) contributed from adiabatic warming and the passage of LPS was the main factor in the acceleration of the surface wind in the leeward side of the mountains. The detailed 3D winds revealed that the PGF also modulated the background winds at the mountainous station, which caused persistent strong and periodic winds (range of ∼7 to ∼12 m s−1) related to the channeling effect. The evidence showed that under the same synoptic condition of a LPS, different mechanisms are important for strong winds in determining the strength and persistence of orographic‐induced strong winds under clear‐air conditions.

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“…Bóra típusú lejtőviharok a Föld számos pontján előfordulnak. Oroszországban például a Fekete-tenger partján, Novorosszijszk térségében jellemző (Shestakova et al, 2019). Japánban többfelé előfordulnak lejtőviharok, közülük a legmarkánsabbak a Shikoku szigetének délkeleti részén húzódó hegységből a Filippinó-tenger partjára lecsapó Yamaji-kaze és a Tokió közelében kialakuló, a Csendes-óceán irányába fújó Hirodo-kaze, melyek jellemzően tájfunokhoz kötődően jönnek létre (Kusaka és Fudeyasu, 2017).…”

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Az adriai bórától a bakonyi lejtőviharig

Kurcsics¹,

Horváth²

2022

Légkör

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A Föld számos pontján megfigyelhető, hogy bizonyos időjárási helyzetekben az alapáramlás és a domborzati (orografikus) hatások eredményeként sajátos szélviszonyok alakulnak ki, melyek akár igen heves szélrohamokat is eredményezhetnek. Ezeknek a szeleknek minden területen megvan a maga neve, az Alpokban ilyen a főn, a Keleti-Kárpátokban a nemere, az Adriai-tenger térségében a bóra. Főnszerű szelek az Alpok mellett előfordulnak többek között a Skandináv-hegységben és a Pireneusokban is, de Magyarországon is többször megfigyelhető főnös hatás (például Tüskés, 2010). A bóra létrejöttében sok tényező játszik szerepet, így nem csoda, hogy az elmúlt évtizedekben, a numerikus modellek fejlődésének köszönhetően sokat módosult a kialakulását magyarázó elmélet.

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Hydraulic and Wave Aspects of Novorossiysk Bora

Cited by 3 publications

References 39 publications

The dependence of mountain wave reflection on the abruptness of atmospheric profile variations

The dependence of mountain wave reflection on the abruptness of atmospheric profile variations

Orographic‐Induced Strong Wind Associated With a Low‐Pressure System Under Clear‐Air Condition During ICE‐POP 2018

Az adriai bórától a bakonyi lejtőviharig

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