First results from the surface heterogeneity focus area of the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) Experiment

The BLLAST experiment was conducted from 14 June - 8 July 2011 in Lannemezan, France with the aim of gaining improved understanding of various transitory processes associated with the afternoon boundary layer. A sub-focus area of the BLLAST experiment was dedicated to studying the impact of surface heterogeneity on various aspects of the afternoon transition and decay processes. The three adjacent vegetative surfaces: corn, moor and forest were instrumented with high frequency continuous monitoring surface energy balance and trace-gas flux stations. In addition, during Intensive Observational Periods, measurements of lower frequency typical meteorological variables were acquired using tethered balloon soundings and unmanned aerial vehicle (UAV) vertical profiles and horizontal surveys. Frequent radio soundings, remote sensing and aircraft measurements provided an important context for larger scales processes that interact with local scale heterogeneity. This talk will present the first results from the surface heterogeneity experiment, and will address several areas of inquiry including: variability in timing according the surface energy balance, impact of induced local breezes, variability in turbulence scales, and variability in the transport of heat, momentum, and scalars.