Mean and flux horizontal variability of virtual potential temperature, moisture, and carbon dioxide: Aircraft observations and LES Study

A first attempt is made to estimate the ratios of the flux at the entrainment zone to the surface flux (entrainment ratios) as a function of longitude. The entrainment ratios averaged from these observations (Î²Î¸Ï â‰ˆ 0.10, βq ≈ −2.4, and βCO2 ≈ −0.58) are similar to the values found from the homogeneous LES experiment with initial and boundary conditions similar to observations. To understand how surface flux heterogeneity influences turbulent fluxes higher up, a heterogeneous LES experiment is performed in a domain with higher sensible and lower latent heat fluxes in the western half compared to the eastern half.

In contrast to the aircraft measurements, the LES turbulent fluxes show a difference in magnitude between the eastern and western halves at 70 and 700 m above ground level. Possible reasons for these differences between results from LES and aircraft measurements are discussed.