Estimation of the vertical turbulent diffusivity from thoron profiles

Abstract

Field measurements of the vertical Tn profiles were carried out on the university campus. On comparison of the observed Tn profiles with those calculated by assuming K = a + bz, some discrepancies were found between them. Profiles of the vertical diffusivity K were estimated from observed Tn profiles. It was found that the estimated K profiles may be expressed well by an experimental formula; KTn(z) = azβ. Some discrepancies were found between the diffusivity KTn estimated from Tn profiles and the diffusivity KM calculated from wind speed by assuming neutral stability. These discrepancies are discussed in relation to the stability of the atmosphere.