Turbulent pressure fluctuations measured during CHATS

Fast-response pressure sensors were deployed during the Canopy Horizontal Array Turbulence Study (CHATS) field campaign, since pressure fluctuations are expected to have a signficant role in the generation of turbulence kinetic energy (TKE) in the roughness sublayer in and near the orchard canopy. Also, it was desired to validate pressure fields associated with LES simulations of coherent structures close to the canopy. Two different sensors were used. They were deployed initially together just above the canopy for intercomparison. Later one was moved to the CHATS horizontal array where it was moved between 3 heights within the canopy. Both sensors were deployed in close proximity to three-dimensional sonic anemometers to calculate the pressure term in various budget equations. Wind tunnel measurements as well as spectra and horizontal heat flux budgets calculated from the intercomparison period are presented to demonstrate the quality of these observations. We also present an attempt to calculate the TKE budget.