Wind and Temperature Variations during Development of a Low-Level Jet

Izumi, Yutaka; Barad, Morton L.

doi:10.1175/1520-0450(1963)002<0668:watvdd>2.0.co;2

Cited by 26 publications

(16 citation statements)

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“…With weakening stability, a became smaller from 59.2" at the beginning of the night to 43.4" in the morning. These results are comparable with the observations of a LLJ at the Cedar Hill tower, Dallas (Izumi and Barad, 1963). Deardorff (197 1) reproduced these soundings numerically.…”

Section: Nocturnalmean Statesupporting

confidence: 81%

“…From these profiles, turbulent fluxes of heat and momentum, coefficients of eddy diffusivity and boundary-layer parameters were estimated. The nocturnal mean state analysis agrees well with the second-order model results of Brost and Wyngaard (1978) and our own first-order numerical testing while the time histories of different profile groups are in accordance with the observations of Izumi and Barad (1963). …”

supporting

confidence: 88%

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A case study of nocturnal wind and temperature profiles over the inhomogeneous terrain of Northern Germany with some considerations of turbulent fluxes

Wittich

Roth

1984

Boundary-Layer Meteorol

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Soundings in the stably-stratified boundary layer were executed over the rough terrain of Northern Germany during a night with a low-level jet (LU) development. Vertical wind and temperature profiles were obtained at 5 m height intervals using a tethersonde transported up and down along a 300 m high radio tower by an elevator. From these profiles, turbulent fluxes of heat and momentum, coefficients of eddy diffusivity and boundary-layer parameters were estimated. The nocturnal mean state analysis agrees well with the second-order model results of Brost and Wyngaard (1978) and our own first-order numerical testing while the time histories of different profile groups are in accordance with the observations of Izumi and Barad (1963).

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Section: Nocturnalmean Statesupporting

confidence: 81%

supporting

confidence: 88%

A case study of nocturnal wind and temperature profiles over the inhomogeneous terrain of Northern Germany with some considerations of turbulent fluxes

Wittich

Roth

1984

Boundary-Layer Meteorol

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“…It has long been documented that, during the spring and summer time, the Great Plains of the US is characterized by frequent nocturnal low-level jets which are often associated with severe weather events such as thunderstorms [4][5][6][7][8][9]. Specifically, Bonner [4] examined the geographical distribution and diurnal variations of the low-level jet over the US based on the 2-yr radiosonde data.…”

Section: Introductionmentioning

confidence: 99%

Wind Resource Assessment in the Southern Plains of the US: Characterizing Large-Scale Atmospheric Circulation with Cluster Analysis

Dong

2018

Atmosphere

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Abstract:A new approach for wind resource assessment in the Southern Plains of the US is proposed here. This new approach establishes the baseline frequency of occurrence of large-scale atmospheric circulations (weather regimes) by cluster analysis, using 38-yr NCEP-NCAR reanalysis daily data from 1979-2016. These baseline frequency values can help quantify the departure of wind resource from the long-term mean for a given month. In specific, two scenarios featuring favorable and unfavorable wind energy productions in the Callahan Divide Energy Center of Texas, US, are evaluated by the new approach of wind resource assessment in details. For the favorable scenario, it is found that the jet stream is configured to enhance the southwesterly flow over the Southern Plains, with a frequency of occurrence being nearly three times of the baseline frequency, whereas for the unfavorable scenario, the jet stream is found to suppress the low-level jet over the Southern Plains, with a frequency of occurrence being more than twice the baseline frequency. Hence, the new approach is proven to provide an objective and more efficient way in conducting wind resource assessment.

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“…However, it is not sufficient to test MOST using turbulence statistics (such as the standard deviation of w (σ w ) and momentum fluxes) which mainly represent active eddies because of the possibility of interaction between inactive and active eddies even in the stable boundary layer (McNaughton and Brunet, 2002). In addition, LLJs play an important role in the large scale water budget and in thermal mixing by transporting water vapor (Corsmeier et al, 1997;Whiteman et al, 1997;Stensrud, 1996;Izumi and Barad, 1963). But it has not been extensively quantified how much a LLJ transports CO 2 and water vapor inside stable boundary layer.…”

Section: Introductionmentioning

confidence: 99%

“…The transport through LLJ2 and the suspected presence of a drainage flow indirectly suggests the existence of warm advection. Izumi and Barad (1963) and Whiteman et al (1997) showed that the SBL temperature profile was influenced by mixing associated with the LLJ. In addition to turbulent mixing, our data set shows that not only water vapor, but also CO 2 and temperature were significantly transported by the LLJ inside the stable boundary layer.…”

mentioning

confidence: 99%

Response of Ecosystem Carbon and Water Vapor Exchanges in Evolving Nocturnal Low-Level Jets

Hong¹,

Mathieu²,

Strachan³

et al. 2012

Asian J. Atmos. Environ

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The nocturnal low-level jet makes a significant impact on carbon and water exchanges and turbulent mixing processes in the atmospheric boundary layer. This study reports a case study of nocturnal surface fluxes such as CO 2 and water vapor in the surface layer observed at a flat and homogeneous site in the presence of low-level jets (LLJs). In particular, it documents the temporal evolution of the overlying jets and the coincident response of surface fluxes. The present study highlights several factors linking the evolution of low-level jets to surface fluxes: 1) wavelet analysis shows that turbulent fluxes have similar time scales with temporal scale of LLJ evolution; 2) turbulent mixing is enhanced during the transition period of low-level jets; and 3) CO 2 , water vapor and heat show dissimilarity from momentum during the period. We also found that LLJ activity is related not only to turbulent motions but also to the divergence of mean flow. An examination of scalar profiles and turbulence data reveal that LLJs transport CO 2 and water vapor by advection in the stable boundary layer, suggesting that surface fluxes obtained from the micrometeorological method such as nocturnal boundary layer budget technique should carefully interpreted in the presence of LLJs.

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Wind and Temperature Variations during Development of a Low-Level Jet

Cited by 26 publications

References 0 publications

A case study of nocturnal wind and temperature profiles over the inhomogeneous terrain of Northern Germany with some considerations of turbulent fluxes

A case study of nocturnal wind and temperature profiles over the inhomogeneous terrain of Northern Germany with some considerations of turbulent fluxes

Wind Resource Assessment in the Southern Plains of the US: Characterizing Large-Scale Atmospheric Circulation with Cluster Analysis

Response of Ecosystem Carbon and Water Vapor Exchanges in Evolving Nocturnal Low-Level Jets

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