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Proceedings with Extended Abstracts (single PDF file) - Radio ...

Proceedings with Extended Abstracts (single PDF file) - Radio ...

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This linear equation relates the intensities of the horizontal turbulent velocities uthe horizontal momentum flux uv to “measurable” parameters a , c , and 2 2d2,auto2,v2, andof auto andcross SF for the received signals. The mean velocities U and V can be estimated from“measurable” coefficients a 2and b2(PP, sec. 3.4). The characteristicscan be estimated uniquely by applying Eq. (7) to the coefficients a 2( x mk),d2, auto( x r a,k) for any three non-parallel baselines ∆xr mkat ( m≠ n)= 1, 2, ..., N.2 2u , v , and uv∆ r c ( ),2∆x rmkandFigure 1. Time series of the turbulence characteristics on 11/16/98 (left column) and11/23/98 (right column) showing STARS (blue bullets) and sonic (red crosses) results.304The NCAR MAPR is a modified version of the commercially available Radian LAP-3000915-MHz boundary layer pro<strong>file</strong>r. Modifications allow this radar to be used as a SA system,<strong>with</strong> the full (four panel) antenna used to transmit and each <strong>single</strong> antenna panel receivingbackscattered energy processed through four independent receiving channels. In November1998, MAPR was operated at the NOAA Boulder Atmospheric Observatory in Erie,Colorado. The experiment included a sonic anemometer atop a 300-m tower, and MAPR waslocated approximately 600 m south of the tower; see Cohn et al. (2001) for details of theexperiment. MAPR received signals in clear-air conditions were analyzed for two timeperiods of about six hours each when signal-to-noise ratio (SNR) was sufficiently high.During the selected periods, SNR after 254 coherent and 7 incoherent integrations varied inthe range of approximately ± 10 dB. The mean horizontal winds U , V , and characteristicsof turbulencew2,u2,2v , and uv were estimated <strong>with</strong> STARS at an averaging timeof Tav= 286 s which is close enough to T av= 5 min. for a sonic anemometer. This paperfocuses on turbulence, and the mean winds are not presented. A detailed comparison of theSTARS and FCA results for U , V , and2w <strong>with</strong> those by a sonic anemometer is

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