Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars
<p>At millimeter wavelengths, attenuation by hydrometeors, such as liquid droplets or large snowflakes, is generally not negligible. When using multifrequency ground-based radar measurements, it is common practice to use the Rayleigh targets at cloud top as a reference in order to derive atten...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-09-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/13/5065/2020/amt-13-5065-2020.pdf |
| _version_ | 1818575660512182272 |
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| author | F. Tridon A. Battaglia A. Battaglia S. Kneifel |
| author_facet | F. Tridon A. Battaglia A. Battaglia S. Kneifel |
| author_sort | F. Tridon |
| collection | DOAJ |
| description | <p>At millimeter wavelengths, attenuation by hydrometeors, such as liquid droplets or large snowflakes, is generally not negligible. When using multifrequency ground-based radar measurements, it is common practice to use the Rayleigh targets at cloud top as a reference in order to derive attenuation-corrected reflectivities and meaningful dual-frequency ratios (DFRs). By capitalizing on this idea, this study describes a new quality-controlled approach that aims at identifying regions of cloud where particle growth is negligible. The core of the method is the identification of a “Rayleigh plateau”, i.e., a large enough region near cloud top where the vertical gradient of DFR remains small.</p>
<p>By analyzing co-located K<span class="inline-formula"><sub>a</sub></span>–W band radar and microwave radiometer (MWR) observations taken at two European sites under various meteorological conditions, it is shown how the resulting estimates of differential path-integrated attenuation (<span class="inline-formula">Δ</span>PIA) can be used to characterize hydrometeor properties. When the <span class="inline-formula">Δ</span>PIA is predominantly produced by cloud liquid droplets, this technique alone can provide accurate estimates of the liquid water path. When combined with MWR observations, this methodology paves the way towards profiling the cloud liquid water, quality-flagging the MWR retrieval for rain and drizzle contamination, and/or estimating the snow differential attenuation.</p> |
| first_indexed | 2024-12-15T00:43:54Z |
| format | Article |
| id | doaj.art-e92f1be04cb34457aa4495c82ad3431f |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-15T00:43:54Z |
| publishDate | 2020-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-e92f1be04cb34457aa4495c82ad3431f2022-12-21T22:41:35ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482020-09-01135065508510.5194/amt-13-5065-2020Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radarsF. Tridon0A. Battaglia1A. Battaglia2S. Kneifel3Institute for Geophysics and Meteorology, University of Cologne, Cologne, GermanyDepartment of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Turin, ItalyDepartment of Physics and Astronomy, University of Leicester, Leicester, UKInstitute for Geophysics and Meteorology, University of Cologne, Cologne, Germany<p>At millimeter wavelengths, attenuation by hydrometeors, such as liquid droplets or large snowflakes, is generally not negligible. When using multifrequency ground-based radar measurements, it is common practice to use the Rayleigh targets at cloud top as a reference in order to derive attenuation-corrected reflectivities and meaningful dual-frequency ratios (DFRs). By capitalizing on this idea, this study describes a new quality-controlled approach that aims at identifying regions of cloud where particle growth is negligible. The core of the method is the identification of a “Rayleigh plateau”, i.e., a large enough region near cloud top where the vertical gradient of DFR remains small.</p> <p>By analyzing co-located K<span class="inline-formula"><sub>a</sub></span>–W band radar and microwave radiometer (MWR) observations taken at two European sites under various meteorological conditions, it is shown how the resulting estimates of differential path-integrated attenuation (<span class="inline-formula">Δ</span>PIA) can be used to characterize hydrometeor properties. When the <span class="inline-formula">Δ</span>PIA is predominantly produced by cloud liquid droplets, this technique alone can provide accurate estimates of the liquid water path. When combined with MWR observations, this methodology paves the way towards profiling the cloud liquid water, quality-flagging the MWR retrieval for rain and drizzle contamination, and/or estimating the snow differential attenuation.</p>https://amt.copernicus.org/articles/13/5065/2020/amt-13-5065-2020.pdf |
| spellingShingle | F. Tridon A. Battaglia A. Battaglia S. Kneifel Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars Atmospheric Measurement Techniques |
| title | Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars |
| title_full | Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars |
| title_fullStr | Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars |
| title_full_unstemmed | Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars |
| title_short | Estimating total attenuation using Rayleigh targets at cloud top: applications in multilayer and mixed-phase clouds observed by ground-based multifrequency radars |
| title_sort | estimating total attenuation using rayleigh targets at cloud top applications in multilayer and mixed phase clouds observed by ground based multifrequency radars |
| url | https://amt.copernicus.org/articles/13/5065/2020/amt-13-5065-2020.pdf |
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