Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation
<p>The cloud-profiling radar (CPR) on the Earth Clouds, Aerosol, and Radiation Explorer (EarthCARE) satellite (EC-CPR) is the first satellite-borne Doppler radar. In a previous study, we examined the effects of horizontal (along-track) integration and simple unfolding methods on the reduction...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-06-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/3211/2023/amt-16-3211-2023.pdf |
| _version_ | 1797794089267101696 |
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| author | Y. Hagihara Y. Ohno H. Horie W. Roh M. Satoh T. Kubota |
| author_facet | Y. Hagihara Y. Ohno H. Horie W. Roh M. Satoh T. Kubota |
| author_sort | Y. Hagihara |
| collection | DOAJ |
| description | <p>The cloud-profiling radar (CPR) on the Earth Clouds,
Aerosol, and Radiation Explorer (EarthCARE) satellite (EC-CPR) is the first
satellite-borne Doppler radar. In a previous study, we examined
the effects of horizontal (along-track) integration and simple unfolding
methods on the reduction of Doppler errors in the EC-CPR observations, and
those effects were evaluated using two limited scenes in limited-latitude
and low-pulse-repetition-frequency (PRF) settings. In this study, the amount
of data used was significantly increased, and the area of the data used was
extended globally. Not only low-PRF but also high-PRF settings were
examined. We calculated the EC-CPR-observed Doppler velocity from pulse-pair
covariances using the radar reflectivity factor and Doppler velocity
obtained from a satellite data simulator and a global storm-resolving
simulation. The global data were divided into five latitudinal zones, and
each standard deviation of Doppler errors for 5 dB<span class="inline-formula"><i>Z</i><sub>e</sub></span> after 10 km
integration was calculated. In the case of the low-PRF setting, the error
without unfolding correction for the tropics reached a maximum of 2.2 m s<span class="inline-formula"><sup>−1</sup></span> and then decreased toward the poles (0.43 m s<span class="inline-formula"><sup>−1</sup>)</span>. The error
with unfolding correction for the tropics became much smaller at 0.63 m s<span class="inline-formula"><sup>−1</sup></span>. In the case of the high-PRF setting, the error without unfolding
correction for the tropics reached a maximum of 0.78 m s<span class="inline-formula"><sup>−1</sup></span> and then
decreased toward the poles (0.19 m s<span class="inline-formula"><sup>−1</sup>)</span>. The error with unfolding
correction for the tropics was 0.29 m s<span class="inline-formula"><sup>−1</sup></span>, less than half the value
without the correction. The results of the analyses of the simulated data
indicated that the zonal mean frequency of precipitation echoes was highest
in the tropics and decreased toward the poles. Considering a limitation of
the unfolding correction for discrimination between large upward velocity
and large precipitation falling velocity, the latitudinal variation in the
standard deviation of Doppler error can be explained by the precipitation
echo distribution.</p> |
| first_indexed | 2024-03-13T02:56:41Z |
| format | Article |
| id | doaj.art-98e0c3e105094e19b6cda7ff90c04b26 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-03-13T02:56:41Z |
| publishDate | 2023-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-98e0c3e105094e19b6cda7ff90c04b262023-06-28T04:19:11ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482023-06-01163211321910.5194/amt-16-3211-2023Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulationY. Hagihara0Y. Ohno1H. Horie2W. Roh3M. Satoh4T. Kubota5Radio Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, JapanRadio Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, JapanRadio Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, JapanAtmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, JapanAtmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, JapanEarth Observation Research Center, Japan Aerospace Exploration Agency, Tsukuba, Ibaraki 305-8505, Japan<p>The cloud-profiling radar (CPR) on the Earth Clouds, Aerosol, and Radiation Explorer (EarthCARE) satellite (EC-CPR) is the first satellite-borne Doppler radar. In a previous study, we examined the effects of horizontal (along-track) integration and simple unfolding methods on the reduction of Doppler errors in the EC-CPR observations, and those effects were evaluated using two limited scenes in limited-latitude and low-pulse-repetition-frequency (PRF) settings. In this study, the amount of data used was significantly increased, and the area of the data used was extended globally. Not only low-PRF but also high-PRF settings were examined. We calculated the EC-CPR-observed Doppler velocity from pulse-pair covariances using the radar reflectivity factor and Doppler velocity obtained from a satellite data simulator and a global storm-resolving simulation. The global data were divided into five latitudinal zones, and each standard deviation of Doppler errors for 5 dB<span class="inline-formula"><i>Z</i><sub>e</sub></span> after 10 km integration was calculated. In the case of the low-PRF setting, the error without unfolding correction for the tropics reached a maximum of 2.2 m s<span class="inline-formula"><sup>−1</sup></span> and then decreased toward the poles (0.43 m s<span class="inline-formula"><sup>−1</sup>)</span>. The error with unfolding correction for the tropics became much smaller at 0.63 m s<span class="inline-formula"><sup>−1</sup></span>. In the case of the high-PRF setting, the error without unfolding correction for the tropics reached a maximum of 0.78 m s<span class="inline-formula"><sup>−1</sup></span> and then decreased toward the poles (0.19 m s<span class="inline-formula"><sup>−1</sup>)</span>. The error with unfolding correction for the tropics was 0.29 m s<span class="inline-formula"><sup>−1</sup></span>, less than half the value without the correction. The results of the analyses of the simulated data indicated that the zonal mean frequency of precipitation echoes was highest in the tropics and decreased toward the poles. Considering a limitation of the unfolding correction for discrimination between large upward velocity and large precipitation falling velocity, the latitudinal variation in the standard deviation of Doppler error can be explained by the precipitation echo distribution.</p>https://amt.copernicus.org/articles/16/3211/2023/amt-16-3211-2023.pdf |
| spellingShingle | Y. Hagihara Y. Ohno H. Horie W. Roh M. Satoh T. Kubota Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation Atmospheric Measurement Techniques |
| title | Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation |
| title_full | Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation |
| title_fullStr | Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation |
| title_full_unstemmed | Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation |
| title_short | Global evaluation of Doppler velocity errors of EarthCARE cloud-profiling radar using a global storm-resolving simulation |
| title_sort | global evaluation of doppler velocity errors of earthcare cloud profiling radar using a global storm resolving simulation |
| url | https://amt.copernicus.org/articles/16/3211/2023/amt-16-3211-2023.pdf |
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