Vertical transport of heat by turbulence in the atmosphere

Abstract

A necessary consequence o f the classical theory o f the turbulent transfer of heat in the atmosphere is that the flux o f heat is in the direction from high to low potential temperature, and this normally involves the flux being from low to high actual temperature. On exam ina tion this is shown to be consistent w ith the second law of thermodynamics.However, the theory assumes that an eddy m ay be regarded as a normal sample o f the population at its level of origin; but when account is taken of buoyancy effects in a necessarily heterogeneous atmosphere it is clear that this assumption is incorrect. It also becomes apparent in the discussion that a definition of the concept ' level of origin ' of an eddy more rigid than that given in the classical theory is necessary, and this has been given. I t is shown that a component of heat flux, here called 'convective turbulence', m ust result from the buoyancy forces. This is always directed upwards and is thus opposed to the general downward transfer of mechanical turbulence.Records of the fluctuations in temperature at fixed levels show amplitudes which cannot be explained by mechanical turbulence. The traces further indicate that convective turbulence m ay at tim es com pletely dominate the direction o f the flow o f heat, a conclusion which is supported by reference to some synoptic examples. This result helps to explain the normal increase of potential temperature with height.Dimensional considerations provide a rough measure of the dependence of the buoyancy flux on the lapse rate and amplitude of fluctuations, and also allow the total flux to be written in the classical form pcv K K \ which m ay be positive or negative, will depend upon the synoptic situation. Some of the implications in synpotic and general theoretical meteorology are discussed in detail. The turbulent transfer o f physical quantities other than heat is briefly considered.

Stellar Mixing Length Theory With Entropy Rain

“…THE DEARDORFF FLUX 3.1. Derivation In the meteorological context, counter-gradient heat flux terms have been noticed for a long time (Ertel 1942;Priestley & Swinbank 1947;Deardorff 1966). They appear naturally when calculating the enthalpy flux F enth using the τ approximation in its minimalistic form (e.g.…”

Technical note: Time lag correction of aquatic eddy covariance data measured in the presence of waves

“…One of them is that procedures for calculating fluxes from raw data must be refined to minimize errors and uncertainties that may be unique to aquatic applications. The procedures used today are largely adapted directly from atmospheric boundary layer research, where the eddy covariance technique has been used for more than 6 decades (Priestley and Swinbank, 1947;Swinbank, 1951).…”

The study of density-stratified flows up to 1945 part 2 Internal waves and interfacial effects

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