Understanding Urban HOST Hypothesis with SURF Field Data

Using the observation over flat terrain, Sun et al. (2016) proposed the HOckey Stick Transition (HOST) hypothesis, which emphasizes contributions of large coherent eddies in atmospheric turbulent mixing that are not fully captured by Monin-Obukhov similarity theory. Using the field data from the Study of Urban Rainfall-Impacts and Fog/Haze (SURF), similar HOST of any TKE-related variables between stable and nearly neutral regimes is found over urban canopies, and the role of large coherent eddies over urban canopies is confirmed. In addition, impacts of variations of urban surface roughness and daytime fog/haze conditions on the nighttime HOST are noted particularly important for urban environment.

Sun, J. and D. H. Lenschow and M. A. LeMone and L. Mahrt, 2016: The role of large-coherent-eddy transport in the atmospheric surface layer based on CASES-99 observations. Bound.-Layer Meteor., 2016, 160(1), 83-111.