Diurnal Variation of Wind and Temperature Fields in the Ekman Layer

Yamamoto, Giichi; Shimanuki, Atsushi; Aida, Masaru; Yasuda, Nobuhisa

doi:10.2151/jmsj1965.51.6_377

Cited by 16 publications

(6 citation statements)

References 7 publications

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“…Below the 85 m level, wind speeds show minimum values near sunrise and sunset. Sasamori's model produced minima of wind speed near sunrise and sunset, but not that of Yamamoto et al (1973). Sasamori (1970) and Yamamoto et al (1973) of wind in the atmospheric boundary layer.…”

Section: Typical Diurnal Variationsmentioning

confidence: 87%

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Turbulent diffusivity and diurnal variations in the atmospheric boundary layer

Yasuda¹

1988

Boundary-Layer Meteorol

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Diurnal variations of the vertical profiles of wind and temperature have been surveyed, and the diffusivity and the dimensionless gradient function in the atmospheric boundary layer have been estimated. Even in the middle of the atmospheric boundary layer (e.g., below a height of 442 m), the vertical wind profile normahzed by the surface friction velocity has approximately a universal profile function different from that in the surface boundary layer. Under strong stability conditions, the dimensionless gradient function has a value of about 9.

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Section: Typical Diurnal Variationsmentioning

confidence: 87%

“…In Figure 2, the geostrophic wind becomes large in the daytime, but the wind speed at 172, 261, 350, and 442 m decreases. Sasamori (1970) and Yamamoto et al (1973) of wind in the atmospheric boundary layer. Below the 85 m level, wind speeds show minimum values near sunrise and sunset.…”

Section: Typical Diurnal Variationsmentioning

confidence: 99%

Turbulent diffusivity and diurnal variations in the atmospheric boundary layer

Yasuda¹

1988

Boundary-Layer Meteorol

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“…A low-level jet, which is an essential feature of the PBL model (e.g., mula. Surface skin temperature is estimated by solv- Blackadar 1957, Yamamoto et al 1973, is also qualiing the surface heat budget equation. Soil temperature tatively reproduced at the 210.5 m level.…”

Section: Description Of the Numerical Model And Design Of Numerical Ementioning

confidence: 99%

Effects of Solar Radiation Amount and Synoptic-scale Wind on the Local Wind "Karakkaze" over the Kanto Plain in Japan

Kusaka

Miya

Ikeda

2011

Journal of the Meteorological Society of Japan

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A climatological and numerical study of "Karakkaze," a type of local wind in Japan, was conducted. First, winter days under a winter-type synoptic pressure pattern with daily minimum relative humidity of less than 40% were classified according to strong wind (wind speed � 9 ms −1 , Karakkaze day), medium wind (6 ms −1 � wind speed < 9 ms −1 ), and weak wind (wind speed < 6 ms −1 ). Secondly, the spatial patterns of the surface wind in each category are confirmed by the Japan Meteorological Agency (JMA)-Automated Meteorological Data Acquisition System (AMeDAS) observation data. In addition, we compared the boundary-layer wind of the three categories using wind speed data from the observation tower of the Meteorological Research Institute (MRI) in Tsukuba and from the JMA wind profiler in Kumagaya. Finally, we performed one-dimensional numerical experiments using a column Planetary Boundary Layer (PBL) model to evaluate the impact of solar radiation and upper-level wind on the formation of the Karakkaze.The results are summarized as follows. On the strong-wind days, strong northwesterly winds appear in the area along the Arakawa River and the Tonegawa River from Maebashi. The surface wind speed has a clear diurnal variation with a peak in the early afternoon. Such a diurnal variation is observed up to a 200 m level, but this diurnal pattern nearly reverses itself between 200 m and 400 m levels. On weak-wind days, the diurnal variation pattern is similar to that in other two categories, but the reversed pattern appears at a 100 m level, not at a 200 m level.Stronger surface winds appear under a clearer winter-type pressure pattern. The correlation coefficient is 0.632 between the daily maximum surface wind speed and the daily mean wind speed at a height of 2759 m, whereas the correlation is 0.284 between the surface wind speed and daily sunshine duration, which, in a previous study, was suggested to be the most significant factor.Numerical experiments indicate that a large amount of solar radiation is a necessary condition for a strong daytime wind, but this is not a sufficient explanation for the difference in the surface wind speed between weak and strong-wind days.

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“…Thus K is allowed to depend on height, thermal stability, local gradients of potential temperature, etc. Numerous authors including O'Brien [1970], Yamamoto et al [1973], Businger and Arya [1974], Orlanski et al [1974], Pielke and Mahrer [1975], Deardorff [1975], Brost and Wyngaard [1978], and Bodin [1980] have considered this approach to study a variety of atmospheric conditions. In the steady, horizontally homogeneous stable boundary layer, Brost and Wyngaard [1978] parameterized K based on surface layer and mixed layer scaling, while Businger and Arya [1974] used a scheme in which K adjusts asymptotically throughout the boundary layer (see Table 1 for a description of K profile schemes).…”

Section: T -•Z Kh •Z •T --•Z Kq •Zzmentioning

confidence: 99%

A review and comparative evaluation of multilevel boundary layer parameterizations for first‐order and turbulent kinetic energy closure schemes

Holt¹,

Raman²

1988

Reviews of Geophysics

129

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Multilevel parameterizations of the atmospheric boundary layer using first‐order and turbulent kinetic energy (TKE) closure schemes are reviewed. Eleven schemes, chosen as representative of both first‐order and TKE closure, are then used for comparison in a one‐dimensional barotropic planetary boundary layer model. TKE closure schemes evaluated are the E‐ε schemes in which eddy viscosity Km is determined from turbulent kinetic energy and energy dissipation ε and the l model schemes in which Km is determined from TKE and mixing length l. Comparison of model simulations of mean and turbulence structure for first‐order closure and TKE closure schemes to observational data (MONEX79) is given. The two main conclusions drawn from this comparison are that (1) the mean structure of the boundary layer is fairly insensitive to the type of closure scheme, given that the scheme properly accounts for turbulent boundary layer mixing, and (2) TKE closure is preferable to first‐order closure in predicting the overall turbulence structure of the boundary layer. Among the TKE schemes compared in this paper, the modified Detering and Etling (1985) scheme is preferred.

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Diurnal Variation of Wind and Temperature Fields in the Ekman Layer

Cited by 16 publications

References 7 publications

Turbulent diffusivity and diurnal variations in the atmospheric boundary layer

Turbulent diffusivity and diurnal variations in the atmospheric boundary layer

Effects of Solar Radiation Amount and Synoptic-scale Wind on the Local Wind "Karakkaze" over the Kanto Plain in Japan

A review and comparative evaluation of multilevel boundary layer parameterizations for first‐order and turbulent kinetic energy closure schemes

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