Research is proposed to improve our understanding of atmosphere- land surface relationships at local and regional scales. The project will involve analysis of the atmospheric boundary layer to study turbulent space-scale relationships. Parameterizations of the Atmospheric Boundary Layer (ABL) transport are critical for quantifying surface fluxes over heterogeneous regions since the ABL integrates regional scale fluxes. The experimental data necessary to carry out the analysis have already been collected: 1) Field (1 km length scale) experiments near UC Davis, 2) Basin (15 km length scale) experiments in Ojai Valley southern California, 3) Regional (100 km length scale) experiments in the Landes Regional in southwestern France as part of HAPEX-MOBILHY. The data collected over the different regions will be analyzed using compactly supported orthonormal wavelet expansions to study spatial intermittency of the surface heat fluxes for various wave numbers in the inertial subrange. In addition dual spectra, which enable a space-scale representation of the turbulent energy, shall be applied to sensible and latent heat fluxes for different atmospheric stability conditions. The spatial probability distribution of the heat fluxes at various scales will be also analyzed. Ultimately this project will provide basic information for the development of models of the ABL to parameterize surface fluxes in general circulation models.
