2002 Annual

Tuesday, 15 January 2002
Quantifying Land-Atmosphere Interactions at the Norman Mesonet Site: A Sensitivity Analysis Using the Oregon State University 1-D PBL Model
Jeffrey B. Basara, Oklahoma Climatological Survey, University of Oklahoma, Norman, OK; and K. C. Crawford and M. B. Ek
In April 1999, the Norman Mesonet site (NORM) was upgraded to include sensors to measure latent, sensible, and ground heat fluxes, as well as net radiation. In addition, over 2,000 discrete soil samples were collected within a 20 X 20 m enclosure encompassing the Norman Mesonet site between 1 June 1999 and 15 August 1999. These samples were collected to provide point-scale observations of soil-water content for field calibration of in situ soil moisture sensors installed at NORM (the Campbell Scientific model 229-L), and to determine the naturally occurring spatial and temporal variability of soil moisture conditions within the outline of the Norman Mesonet site.

Using the Oregon State University (OSU) one-dimensional, coupled atmospheric-plant-soil model, in situ and field observations of soil moisture, atmospheric soundings from the National Weather Service Weather Forecast Office (NWS WFO) in Norman, and atmospheric observations collected at the NORM site, planetary boundary layer conditions were examined at NORM during July 1999. Results indicate that latent and sensible heat fluxes in the model simulations varied by as much as 300 W m-2 due to naturally occurring variability of soil-water content determined from field samples and biases occurring in the in situ measurements. Furthermore, ground heat flux values derived by the model varied as much as 50 W m-2.

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