### Abstract

Original language | English |
---|---|

Journal | Boundary-Layer Meteorology |

Volume | 167 |

Issue number | 3 |

Pages (from-to) | 371-397 |

Number of pages | 27 |

ISSN | 0006-8314 |

DOIs | |

Publication status | Published - 2018 |

### Keywords

- Atmospheric stability
- Atmospheric turbulence
- Boundary layer
- Spectra
- Spectral tensor

### Cite this

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*Boundary-Layer Meteorology*, vol. 167, no. 3, pp. 371-397. https://doi.org/10.1007/s10546-018-0332-z

**Simplification and Validation of a Spectral-Tensor Model for Turbulence Including Atmospheric Stability.** / Chougule, Abhijit; Mann, Jakob; Kelly, Mark C.; Larsen, Gunner Chr.

Research output: Contribution to journal › Journal article › Research › peer-review

TY - JOUR

T1 - Simplification and Validation of a Spectral-Tensor Model for Turbulence Including Atmospheric Stability

AU - Chougule, Abhijit

AU - Mann, Jakob

AU - Kelly, Mark C.

AU - Larsen, Gunner Chr.

PY - 2018

Y1 - 2018

N2 - A spectral-tensor model of non-neutral, atmospheric-boundary-layer turbulence is evaluated using Eulerian statistics from single-point measurements of the wind speed and temperature at heights up to 100 m, assuming constant vertical gradients of mean wind speed and temperature. The model has been previously described in terms of the dissipation rate epsilon, the length scale of energy-containing eddies L, a turbulence anisotropy parameter Gamma, the Richardson number Ri, and the normalized rate of destruction of temperature variance eta(theta) equivalent to epsilon(theta)/epsilon. Here, the latter two parameters are collapsed into a single atmospheric stability parameter z/L usingMonin-Obukhov similarity theory, where z is the height above the Earth's surface, and L is the Obukhov length corresponding to {Ri ,eta(theta)}. Model outputs of the one-dimensional velocity spectra, as well as cospectra of the streamwise and/or vertical velocity components, and/or temperature, and cross-spectra for the spatial separation of all three velocity components and temperature, are compared with measurements. As a function of the four model parameters, spectra and cospectra are reproduced quite well, but horizontal temperature fluxes are slightly underestimated in stable conditions. In moderately unstable stratification, our model reproduces spectra only up to a scale similar to 1 km. The model also overestimates coherences for vertical separations, but is less severe in unstable than in stable cases.

AB - A spectral-tensor model of non-neutral, atmospheric-boundary-layer turbulence is evaluated using Eulerian statistics from single-point measurements of the wind speed and temperature at heights up to 100 m, assuming constant vertical gradients of mean wind speed and temperature. The model has been previously described in terms of the dissipation rate epsilon, the length scale of energy-containing eddies L, a turbulence anisotropy parameter Gamma, the Richardson number Ri, and the normalized rate of destruction of temperature variance eta(theta) equivalent to epsilon(theta)/epsilon. Here, the latter two parameters are collapsed into a single atmospheric stability parameter z/L usingMonin-Obukhov similarity theory, where z is the height above the Earth's surface, and L is the Obukhov length corresponding to {Ri ,eta(theta)}. Model outputs of the one-dimensional velocity spectra, as well as cospectra of the streamwise and/or vertical velocity components, and/or temperature, and cross-spectra for the spatial separation of all three velocity components and temperature, are compared with measurements. As a function of the four model parameters, spectra and cospectra are reproduced quite well, but horizontal temperature fluxes are slightly underestimated in stable conditions. In moderately unstable stratification, our model reproduces spectra only up to a scale similar to 1 km. The model also overestimates coherences for vertical separations, but is less severe in unstable than in stable cases.

KW - Atmospheric stability

KW - Atmospheric turbulence

KW - Boundary layer

KW - Spectra

KW - Spectral tensor

U2 - 10.1007/s10546-018-0332-z

DO - 10.1007/s10546-018-0332-z

M3 - Journal article

VL - 167

SP - 371

EP - 397

JO - Boundary-Layer Meteorology

JF - Boundary-Layer Meteorology

SN - 0006-8314

IS - 3

ER -