Open AccessAn overview of the micrometeorological field campaign at Santa Maria, Southern Brazil: the Pampa‐2016 experiment
Author(s) -
Degrazia Gervásio Annes,
Rizza Umberto,
Stefanello Michel,
Maldaner Silvana,
Roberti Debora Regina,
Martins Luis Gustavo Nogueira,
Anabor Vagner,
Puhales Franciano Scremin,
Dal Piva Everson,
Acevedo Otavio Costa,
Zimermann Hans Rogério,
Teichrieb Cláudio Alberto
Publication year - 2018
Publication title -
meteorological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 59
eISSN - 1469-8080
pISSN - 1350-4827
DOI - 10.1002/met.1711
Subject(s) - radiosonde , daytime , boundary layer , atmospheric sciences , planetary boundary layer , convective boundary layer , environmental science , convection , radiative transfer , potential temperature , meteorology , atmospheric instability , wind speed , radiative cooling , turbulence , radiative flux , surface layer , stratification (seeds) , nocturnal , geology , physics , mechanics , layer (electronics) , materials science , biology , seed dormancy , dormancy , composite material , germination , quantum mechanics , botany , astronomy
The Pampa‐2016 experimental campaign was performed in a typical Pampa lowland South American region. It consisted of both surface flux measurements (at 3 and 29 m) and a radiosonde launched every 3 h. The resulting meteorological observations allowed for the analysis of turbulent properties associated with both a stable and a convective boundary layer. The combined analysis of the surface data and vertical soundings has revealed some general characteristics of the atmospheric boundary layer for both the nocturnal stable conditions and the daytime convective environment. The continuous surface measurements showed that the nocturnal stable inversion, occurring in calm winds, is basically generated by the radiative cooling mechanism that is established after the late afternoon transition. The analysis of night‐time surface data also showed that, under stable conditions in the case of vanishing wind speed, the friction velocity has unrealistic values that are very close to zero. This situation is undesirable for numerical models that generally use this quantity as a lower boundary condition. The analysis of night‐time temperature profiles revealed two contrasting patterns in agreement with the classical classification of radiative night (a very stable boundary layer) and a turbulent night (a weakly stable boundary layer). In contrast, the analysis of the daytime temperature profiles provided an estimation of the convective time scale that is of the order of 10 min, in agreement with experimental values. A spectral analysis and the consequent estimation of the spectral peaks under unstable and stable conditions were in agreement with literature values.