Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size
Abstract A retrieval for characteristic raindrop size and width of the drop size distribution (DSD) based on triple‐frequency vertical Doppler radar measurements is developed. The algorithm exploits a statistical relation that maps measurements of the differential Doppler velocities at X and Ka and...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2020-03-01
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| Series: | Earth and Space Science |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2019EA000789 |
| _version_ | 1811312817026891776 |
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| author | Kamil Mróz Alessandro Battaglia Stefan Kneifel Leo Pio D'Adderio José Dias Neto |
| author_facet | Kamil Mróz Alessandro Battaglia Stefan Kneifel Leo Pio D'Adderio José Dias Neto |
| author_sort | Kamil Mróz |
| collection | DOAJ |
| description | Abstract A retrieval for characteristic raindrop size and width of the drop size distribution (DSD) based on triple‐frequency vertical Doppler radar measurements is developed. The algorithm exploits a statistical relation that maps measurements of the differential Doppler velocities at X and Ka and at Ka and W bands into the two aforementioned DSD moments. The statistical mapping has been founded on 7,900 hr of disdrometer‐observed DSDs and their simulated Doppler velocities. Additionally, a retrieval of Dm based only on DDVX−W measurements is also presented, and its performance is compared to the analogous algorithm exploiting DDVKa−W data. The retrievals are tested using triple‐frequency radar data collected during a recent field campaign held at the Juelich Observatory for Cloud Evolution (JOYCE, Germany) where in situ measurements of the DSD were carried out only few meters away from the vertically pointing radars. The triple‐frequency retrieval is able to obtain Dm with an uncertainty below 25% for Dm ranging from 0.7 to 2.4 mm. Compared to previously published dual‐frequency retrievals, the third frequency does not improve the retrieval for small Dm ( <1.4 mm). However, it significantly surpasses the DDVKa−W algorithm for larger Dm (20% versus 50% bias at 2.25 mm). Also compared to DDVX−W method, the triple‐frequency retrieval is found to provide an improvement of 15% in terms of bias for Dm=2.25 mm. The triple‐frequency retrieval of σm performs with an uncertainty of 20–50% for 0.2<σm<1.3 mm, with the best performance for 0.25<σm<0.8 mm. |
| first_indexed | 2024-04-13T10:43:18Z |
| format | Article |
| id | doaj.art-240545ddb04c45d29df8c7b1bf7d5c2d |
| institution | Directory Open Access Journal |
| issn | 2333-5084 |
| language | English |
| last_indexed | 2024-04-13T10:43:18Z |
| publishDate | 2020-03-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Earth and Space Science |
| spelling | doaj.art-240545ddb04c45d29df8c7b1bf7d5c2d2022-12-22T02:49:52ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842020-03-0173n/an/a10.1029/2019EA000789Triple‐Frequency Doppler Retrieval of Characteristic Raindrop SizeKamil Mróz0Alessandro Battaglia1Stefan Kneifel2Leo Pio D'Adderio3José Dias Neto4National Centre for Earth Observation University of Leicester Leicester UKNational Centre for Earth Observation University of Leicester Leicester UKInstitute for Geophysics and Meteorology University of Cologne Cologne GermanyInstitute of Atmospheric Sciences and Climate ISAC‐CNR National Research Council Rome ItalyInstitute for Geophysics and Meteorology University of Cologne Cologne GermanyAbstract A retrieval for characteristic raindrop size and width of the drop size distribution (DSD) based on triple‐frequency vertical Doppler radar measurements is developed. The algorithm exploits a statistical relation that maps measurements of the differential Doppler velocities at X and Ka and at Ka and W bands into the two aforementioned DSD moments. The statistical mapping has been founded on 7,900 hr of disdrometer‐observed DSDs and their simulated Doppler velocities. Additionally, a retrieval of Dm based only on DDVX−W measurements is also presented, and its performance is compared to the analogous algorithm exploiting DDVKa−W data. The retrievals are tested using triple‐frequency radar data collected during a recent field campaign held at the Juelich Observatory for Cloud Evolution (JOYCE, Germany) where in situ measurements of the DSD were carried out only few meters away from the vertically pointing radars. The triple‐frequency retrieval is able to obtain Dm with an uncertainty below 25% for Dm ranging from 0.7 to 2.4 mm. Compared to previously published dual‐frequency retrievals, the third frequency does not improve the retrieval for small Dm ( <1.4 mm). However, it significantly surpasses the DDVKa−W algorithm for larger Dm (20% versus 50% bias at 2.25 mm). Also compared to DDVX−W method, the triple‐frequency retrieval is found to provide an improvement of 15% in terms of bias for Dm=2.25 mm. The triple‐frequency retrieval of σm performs with an uncertainty of 20–50% for 0.2<σm<1.3 mm, with the best performance for 0.25<σm<0.8 mm.https://doi.org/10.1029/2019EA000789rainDoppler radardrop size distributioncharacteristic sizeretrievaldisdrometer |
| spellingShingle | Kamil Mróz Alessandro Battaglia Stefan Kneifel Leo Pio D'Adderio José Dias Neto Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size Earth and Space Science rain Doppler radar drop size distribution characteristic size retrieval disdrometer |
| title | Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size |
| title_full | Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size |
| title_fullStr | Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size |
| title_full_unstemmed | Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size |
| title_short | Triple‐Frequency Doppler Retrieval of Characteristic Raindrop Size |
| title_sort | triple frequency doppler retrieval of characteristic raindrop size |
| topic | rain Doppler radar drop size distribution characteristic size retrieval disdrometer |
| url | https://doi.org/10.1029/2019EA000789 |
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