A comparison of vertical velocity variance measurements from wind profiling radars and sonic anemometers
Observations of turbulence in the planetary boundary layer are critical for developing and evaluating boundary layer parameterizations in mesoscale numerical weather prediction models. These observations, however, are expensive and rarely profile the entire boundary layer. Using optimized configurat...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-03-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/10/999/2017/amt-10-999-2017.pdf |
| Summary: | Observations of turbulence in the planetary boundary layer are
critical for developing and evaluating boundary layer parameterizations in
mesoscale numerical weather prediction models. These observations, however,
are expensive and rarely profile the entire boundary layer. Using optimized
configurations for 449 and 915 MHz wind profiling radars during the
eXperimental Planetary boundary layer Instrumentation Assessment (XPIA),
improvements have been made to the historical methods of measuring vertical
velocity variance through the time series of vertical velocity, as well as
the Doppler spectral width. Using six heights of sonic anemometers mounted on
a 300 m tower, correlations of up to <i>R</i><sup>2</sup> = 0. 74 are seen in measurements of
the large-scale variances from the radar time series and <i>R</i><sup>2</sup> = 0. 79 in
measurements of small-scale variance from radar spectral widths. The total
variance, measured as the sum of the small and large scales, agrees well with
sonic anemometers, with <i>R</i><sup>2</sup> = 0. 79. Correlation is higher in daytime
convective boundary layers than nighttime stable conditions when turbulence
levels are smaller. With the good agreement with the in situ
measurements, highly resolved profiles up to 2 km can be accurately observed
from the 449 MHz radar and 1 km from the 915 MHz radar. This optimized
configuration will provide unique observations for the verification and
improvement to boundary layer parameterizations in mesoscale models. |
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| ISSN: | 1867-1381 1867-8548 |