Calibrating Differential Reflectivity with QZdrCal: An Open System Radar Product Generator (ORPG) Update with an Upgraded Dry Aggregated Snow Method.
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| Title: | Calibrating Differential Reflectivity with QZdrCal: An Open System Radar Product Generator (ORPG) Update with an Upgraded Dry Aggregated Snow Method. |
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| Authors: | HU, JIAXI1 jhu20@albany.edu, ZHANG, PENGFEI2,3, KRAUSE, JOHN2,3, RYZHKOV, ALEXANDER2,3 |
| Source: | Journal of Atmospheric & Oceanic Technology. Jun2026, Vol. 43 Issue 6, p673-686. 14p. |
| Subjects: | Meteorological precipitation, Snowstorms, Radar signal processing, Coherent radar |
| Abstract: | Accurate calibration of differential reflectivity (ZDR) on polarimetric weather radars remains a challenge. In addition to the internal system calibration, various techniques based on an analysis of the radar data collected are being used in research and operations. In this study, we focus on the use of dry aggregated snow (DAS) routinely observed just above the melting layer (ML) and below the dendritic growth layer (DGL) in stratiform precipitation. We assume that the intrinsic value of ZDR in DAS varies between 0 and 0.25 dB depending on the intensity of snow and its degree of aggregation. By utilizing range-defined quasi-vertical profiles of polarimetric radar variables, we can provide accurate measurements of ZDR bias above the ML or above the surface during a cold-season scenario. The most critical part of the calibration methodology is to identify DAS as opposed to other snow types with a much wider distribution of ZDR. Several criteria for DAS identification have been developed. These include the value of maximum Z and the vertical gradient of Z above the ML top (or surface for the cold season) up to the DGL bottom, the minimal value of the cross-correlation coefficient within the ML (ignored during the cold season), and the height of the storm above the DGL. This calibration technique is tested for a large number of storms and demonstrates high stability and robustness of the ZDR bias estimation with a standard error lower than 0.1 dB. This algorithm has been adopted into the U.S. Open Radar Product Generator system in FY24. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Atmospheric & Oceanic Technology is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 195190425 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Calibrating Differential Reflectivity with QZdrCal: An Open System Radar Product Generator (ORPG) Update with an Upgraded Dry Aggregated Snow Method. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22HU%2C+JIAXI%22">HU, JIAXI</searchLink><relatesTo>1</relatesTo><i> jhu20@albany.edu</i><br /><searchLink fieldCode="AR" term="%22ZHANG%2C+PENGFEI%22">ZHANG, PENGFEI</searchLink><relatesTo>2,3</relatesTo><br /><searchLink fieldCode="AR" term="%22KRAUSE%2C+JOHN%22">KRAUSE, JOHN</searchLink><relatesTo>2,3</relatesTo><br /><searchLink fieldCode="AR" term="%22RYZHKOV%2C+ALEXANDER%22">RYZHKOV, ALEXANDER</searchLink><relatesTo>2,3</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Atmospheric+%26+Oceanic+Technology%22">Journal of Atmospheric & Oceanic Technology</searchLink>. Jun2026, Vol. 43 Issue 6, p673-686. 14p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Meteorological+precipitation%22">Meteorological precipitation</searchLink><br /><searchLink fieldCode="DE" term="%22Snowstorms%22">Snowstorms</searchLink><br /><searchLink fieldCode="DE" term="%22Radar+signal+processing%22">Radar signal processing</searchLink><br /><searchLink fieldCode="DE" term="%22Coherent+radar%22">Coherent radar</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Accurate calibration of differential reflectivity (ZDR) on polarimetric weather radars remains a challenge. In addition to the internal system calibration, various techniques based on an analysis of the radar data collected are being used in research and operations. In this study, we focus on the use of dry aggregated snow (DAS) routinely observed just above the melting layer (ML) and below the dendritic growth layer (DGL) in stratiform precipitation. We assume that the intrinsic value of ZDR in DAS varies between 0 and 0.25 dB depending on the intensity of snow and its degree of aggregation. By utilizing range-defined quasi-vertical profiles of polarimetric radar variables, we can provide accurate measurements of ZDR bias above the ML or above the surface during a cold-season scenario. The most critical part of the calibration methodology is to identify DAS as opposed to other snow types with a much wider distribution of ZDR. Several criteria for DAS identification have been developed. These include the value of maximum Z and the vertical gradient of Z above the ML top (or surface for the cold season) up to the DGL bottom, the minimal value of the cross-correlation coefficient within the ML (ignored during the cold season), and the height of the storm above the DGL. This calibration technique is tested for a large number of storms and demonstrates high stability and robustness of the ZDR bias estimation with a standard error lower than 0.1 dB. This algorithm has been adopted into the U.S. Open Radar Product Generator system in FY24. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Atmospheric & Oceanic Technology is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1175/JTECH-D-25-0123.1 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 14 StartPage: 673 Subjects: – SubjectFull: Meteorological precipitation Type: general – SubjectFull: Snowstorms Type: general – SubjectFull: Radar signal processing Type: general – SubjectFull: Coherent radar Type: general Titles: – TitleFull: Calibrating Differential Reflectivity with QZdrCal: An Open System Radar Product Generator (ORPG) Update with an Upgraded Dry Aggregated Snow Method. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: HU, JIAXI – PersonEntity: Name: NameFull: ZHANG, PENGFEI – PersonEntity: Name: NameFull: KRAUSE, JOHN – PersonEntity: Name: NameFull: RYZHKOV, ALEXANDER IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 06 Text: Jun2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 07390572 Numbering: – Type: volume Value: 43 – Type: issue Value: 6 Titles: – TitleFull: Journal of Atmospheric & Oceanic Technology Type: main |
| ResultId | 1 |
