Comparing spectra and cospectra of turbulence over different surface boundary conditions

Long-term eddy-covariance measurements from the LBA-ECO Project were used to study the behavior of turbulence spectra and cospectra above the Amazon rainforest as well as over a nearby deforested area in the central part of Amazon region. Results are separated according to the wind speed and stability conditions. Under stable low wind speed conditions the Kolmogorov inertial subrange law is not observed. For all other situations simple empirical relations are obtained and length scales associated with the more energetic eddies are calculated. Above the forest canopy, the cospectra are more peaked than those observed over the deforested area, confirming previous observations made over a midlatitude forest.