## Abstract

The probability density functions (pdf's) for the longitudinal and vertical velocities, temperature, their derivatives, and momentum and sensible heat fluxes were measured in the atmospheric surface layer for a wide range of atmospheric stability conditions. The measured pdf's for both the velocity and the temperature fluctuations are near-Gaussian and consistent with corresponding laboratory measurements for near- neutral and stable stability conditions. Hence the first- and second-order moments are sufficient to predict the heat and momentum flux pdf's. The lower- order moments can be estimated from mean meteorological conditions using surface layer similarity theory. For unstable conditions the pdf for temperature is non-Gaussian and is strongly skewed due to local convective thermal plumes. For near-neutral and stable conditions the pdf's for the velocity and temperature longitudinal gradients have long exponential tails, in agreement with findings in laboratory experiments and numerical simulations.

Original language | English |
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Pages (from-to) | 1681-1688 |

Number of pages | 8 |

Journal | Water Resources Research |

Volume | 32 |

Issue number | 6 |

DOIs | |

State | Published - Jun 1996 |