Open AccessLidar Measurement of Boundary Layer Evolution to Determine Sensible Heat Fluxes
Author(s) -
W. E. Eichinger,
H. Holder,
D. I. Cooper,
L. E. Hipps,
R.J. Knight,
William P. Kustas,
Julie Nichols,
John H. Prueger
Publication year - 2005
Publication title -
journal of hydrometeorology (online)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.733
H-Index - 123
eISSN - 1525-755X
pISSN - 1525-7541
DOI - 10.1175/jhm461.1
Subject(s) - sensible heat , eddy covariance , environmental science , entrainment (biomusicology) , planetary boundary layer , boundary layer , atmospheric sciences , bowen ratio , lidar , flux (metallurgy) , potential temperature , latent heat , heat flux , atmosphere (unit) , surface layer , moisture , meteorology , mechanics , geology , materials science , remote sensing , heat transfer , layer (electronics) , physics , biology , ecology , ecosystem , rhythm , acoustics , metallurgy , composite material
The Soil Moisture–Atmosphere Coupling Experiment (SMACEX) was conducted in the Walnut Creek watershed near Ames, Iowa, over the period from 15 June to 11 July 2002. A main focus of SMACEX is the investigation of the interactions between the atmospheric boundary layer, surface moisture, and canopy. A vertically staring elastic lidar was used to provide a high-time-resolution continuous record of the boundary layer height at the edge between a soybean and cornfield. The height and thickness of the entrainment zone are used to estimate the surface sensible heat flux using the Batchvarova–Gryning boundary layer model. Flux estimates made over 6 days are compared to conventional eddy correlation measurements. The calculated values of the sensible heat flux were found to be well correlated (R2 = 0.79, with a slope of 0.95) when compared to eddy correlation measurements in the area. The standard error of the flux estimates was 21.4 W m−2 (31% rms difference between this method and surface measurements), which is somewhat higher than a predicted uncertainty of 16%. The major sources of error were from the estimates of the vertical potential temperature gradient and an assumption that the entrainment parameter A was equal to the ratio of the entrainment flux and the surface heat flux.