Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar
<p>Low-powered commercially available coherent Doppler lidar (CDL) wind profilers provide continuous measurement of vertical profiles of wind in the lower troposphere, usually close to or up to the top of the planetary boundary layer. The vertical extent of these wind profiles is limited by th...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-08-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/3715/2023/amt-16-3715-2023.pdf |
| _version_ | 1797745929750577152 |
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| author | S. Baidar S. Baidar T. J. Wagner D. D. Turner W. A. Brewer |
| author_facet | S. Baidar S. Baidar T. J. Wagner D. D. Turner W. A. Brewer |
| author_sort | S. Baidar |
| collection | DOAJ |
| description | <p>Low-powered commercially available coherent Doppler lidar
(CDL) wind profilers provide continuous measurement of vertical profiles of wind in the
lower troposphere, usually close to or up to the top of the planetary
boundary layer. The vertical extent of these wind profiles is limited by the
availability of scatterers and thus varies substantially throughout the day
and from one day to the next. This makes it challenging to develop
continuous products that rely on CDL-observed wind profiles. In order to
overcome this problem, we have developed a new method for wind profile
retrievals from CDL that combines the traditional velocity-azimuth display
(VAD) technique with optimal estimation (OE) to provide continuous wind
profiles up to 3 km. The new method exploits the level-to-level covariance
present in the wind profile to fill in the gaps where the signal-to-noise
ratio of the CDL return is too low to provide reliable results using the
traditional VAD method. Another advantage of the new method is that it
provides the full error covariance matrix of the solution and profiles of
information content, which more easily facilitates the assimilation of the
observed wind profiles into numerical weather prediction models. This method
was tested using yearlong CDL measurements at the Atmospheric Radiation
Measurement (ARM) Southern Great Plains (SGP) Central Facility in 2019.
Comparison with the ARM operational CDL wind profile product and collocated
radiosonde wind measurements shows excellent agreement (<span class="inline-formula"><i>R</i><sup>2</sup>>0.99</span>) with no degradation in results where the traditional VAD provided a
valid solution. In the region where traditional VAD does not provide
results, the OE wind speed and wind vector have uncertainties of 3.44 and
4.33 m s<span class="inline-formula"><sup>−1</sup></span>, respectively. As a result, the new method provides additional
information over the standard technique and increases the effective range of
existing CDL systems without the need for additional hardware.</p> |
| first_indexed | 2024-03-12T15:30:53Z |
| format | Article |
| id | doaj.art-cc4be734c30643fd9f0bf117aca097c6 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-03-12T15:30:53Z |
| publishDate | 2023-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-cc4be734c30643fd9f0bf117aca097c62023-08-10T06:39:11ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482023-08-01163715372610.5194/amt-16-3715-2023Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidarS. Baidar0S. Baidar1T. J. Wagner2D. D. Turner3W. A. Brewer4Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, USAChemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, USASpace Science and Engineering Center, University of Wisconsin-Madison, Madison, Wisconsin 53706, USAGlobal Systems Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, USAChemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, USA<p>Low-powered commercially available coherent Doppler lidar (CDL) wind profilers provide continuous measurement of vertical profiles of wind in the lower troposphere, usually close to or up to the top of the planetary boundary layer. The vertical extent of these wind profiles is limited by the availability of scatterers and thus varies substantially throughout the day and from one day to the next. This makes it challenging to develop continuous products that rely on CDL-observed wind profiles. In order to overcome this problem, we have developed a new method for wind profile retrievals from CDL that combines the traditional velocity-azimuth display (VAD) technique with optimal estimation (OE) to provide continuous wind profiles up to 3 km. The new method exploits the level-to-level covariance present in the wind profile to fill in the gaps where the signal-to-noise ratio of the CDL return is too low to provide reliable results using the traditional VAD method. Another advantage of the new method is that it provides the full error covariance matrix of the solution and profiles of information content, which more easily facilitates the assimilation of the observed wind profiles into numerical weather prediction models. This method was tested using yearlong CDL measurements at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Central Facility in 2019. Comparison with the ARM operational CDL wind profile product and collocated radiosonde wind measurements shows excellent agreement (<span class="inline-formula"><i>R</i><sup>2</sup>>0.99</span>) with no degradation in results where the traditional VAD provided a valid solution. In the region where traditional VAD does not provide results, the OE wind speed and wind vector have uncertainties of 3.44 and 4.33 m s<span class="inline-formula"><sup>−1</sup></span>, respectively. As a result, the new method provides additional information over the standard technique and increases the effective range of existing CDL systems without the need for additional hardware.</p>https://amt.copernicus.org/articles/16/3715/2023/amt-16-3715-2023.pdf |
| spellingShingle | S. Baidar S. Baidar T. J. Wagner D. D. Turner W. A. Brewer Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar Atmospheric Measurement Techniques |
| title | Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar |
| title_full | Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar |
| title_fullStr | Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar |
| title_full_unstemmed | Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar |
| title_short | Using optimal estimation to retrieve winds from velocity-azimuth display (VAD) scans by a Doppler lidar |
| title_sort | using optimal estimation to retrieve winds from velocity azimuth display vad scans by a doppler lidar |
| url | https://amt.copernicus.org/articles/16/3715/2023/amt-16-3715-2023.pdf |
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