Turbulence regimes and the validity of similarity theory in the stable boundary layer during EBEX-2000

The objective of this work is to investigate the difference of the turbulence characteristics and its structures in the stable stratified atmospheric boundary layer (ABL) during daytime and nighttime. During the Energy Balance Experiment (EBEX-2000) that was conducted in the San Joaquin Valley of California in August 2000, ten flux towers were erected in a flat cotton field. Patch-by-patch irrigation over the field and horizontal advection of dry air from a bare dirt field create an “oasis effect” (stable ABL) in the afternoon. Two groups of data were selected under daytime stable and nighttime stable conditions, to analyze the difference of turbulence characteristics and its structures in the stable ABL during daytime and nighttime using continuous wavelet transform and empirical ensemble mode decomposition. From the continuous wavelet analysis, the comparisons of size and impacts of eddies will be presented in terms of the daytime and nighttime stable conditions. A case study showing the difference of turbulence during daytime and nighttime stable conditions will be illustrated. The validity of Monin-Obukhov similarity theory under daytime and nighttime stable conditions will also be examined.