Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration?
Cloud radars are unique instruments for observing cloud processes, but uncertainties in radar calibration have frequently limited data quality. Thus far, no single robust method exists for assessing the calibration of past cloud radar data sets. Here, we investigate whether observations of microphys...
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ftdoajarticles:oai:doaj.org/article:32f3a5ab115141a0b0e8e51379327686 2023-05-15T17:40:15+02:00 Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? M. Maahn F. Hoffmann M. D. Shupe G. de Boer S. Y. Matrosov E. P. Luke 2019-06-01T00:00:00Z https://doi.org/10.5194/amt-12-3151-2019 https://doaj.org/article/32f3a5ab115141a0b0e8e51379327686 EN eng Copernicus Publications https://www.atmos-meas-tech.net/12/3151/2019/amt-12-3151-2019.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-12-3151-2019 1867-1381 1867-8548 https://doaj.org/article/32f3a5ab115141a0b0e8e51379327686 Atmospheric Measurement Techniques, Vol 12, Pp 3151-3171 (2019) Environmental engineering TA170-171 Earthwork. Foundations TA715-787 article 2019 ftdoajarticles https://doi.org/10.5194/amt-12-3151-2019 2022-12-31T03:47:08Z Cloud radars are unique instruments for observing cloud processes, but uncertainties in radar calibration have frequently limited data quality. Thus far, no single robust method exists for assessing the calibration of past cloud radar data sets. Here, we investigate whether observations of microphysical processes in liquid clouds such as the transition of cloud droplets to drizzle drops can be used to calibrate cloud radars. Specifically, we study the relationships between the radar reflectivity factor and three variables not affected by absolute radar calibration: the skewness of the radar Doppler spectrum ( γ ), the radar mean Doppler velocity ( W ), and the liquid water path (LWP). For each relation, we evaluate the potential for radar calibration. For γ and W , we use box model simulations to determine typical radar reflectivity values for reference points. We apply the new methods to observations at the Atmospheric Radiation Measurement (ARM) sites North Slope of Alaska (NSA) and Oliktok Point (OLI) in 2016 using two 35 GHz K a -band ARM Zenith Radars (KAZR). For periods with a sufficient number of liquid cloud observations, we find that liquid cloud processes are robust enough for cloud radar calibration, with the LWP-based method performing best. We estimate that, in 2016, the radar reflectivity at NSA was about 1±1 dB too low but stable. For OLI, we identify serious problems with maintaining an accurate calibration including a sudden decrease of 5 to 7 dB in June 2016. Article in Journal/Newspaper north slope Alaska Directory of Open Access Journals: DOAJ Articles Atmospheric Measurement Techniques 12 6 3151 3171 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
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Environmental engineering TA170-171 Earthwork. Foundations TA715-787 M. Maahn F. Hoffmann M. D. Shupe G. de Boer S. Y. Matrosov E. P. Luke Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
topic_facet |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
description |
Cloud radars are unique instruments for observing cloud processes, but uncertainties in radar calibration have frequently limited data quality. Thus far, no single robust method exists for assessing the calibration of past cloud radar data sets. Here, we investigate whether observations of microphysical processes in liquid clouds such as the transition of cloud droplets to drizzle drops can be used to calibrate cloud radars. Specifically, we study the relationships between the radar reflectivity factor and three variables not affected by absolute radar calibration: the skewness of the radar Doppler spectrum ( γ ), the radar mean Doppler velocity ( W ), and the liquid water path (LWP). For each relation, we evaluate the potential for radar calibration. For γ and W , we use box model simulations to determine typical radar reflectivity values for reference points. We apply the new methods to observations at the Atmospheric Radiation Measurement (ARM) sites North Slope of Alaska (NSA) and Oliktok Point (OLI) in 2016 using two 35 GHz K a -band ARM Zenith Radars (KAZR). For periods with a sufficient number of liquid cloud observations, we find that liquid cloud processes are robust enough for cloud radar calibration, with the LWP-based method performing best. We estimate that, in 2016, the radar reflectivity at NSA was about 1±1 dB too low but stable. For OLI, we identify serious problems with maintaining an accurate calibration including a sudden decrease of 5 to 7 dB in June 2016. |
format |
Article in Journal/Newspaper |
author |
M. Maahn F. Hoffmann M. D. Shupe G. de Boer S. Y. Matrosov E. P. Luke |
author_facet |
M. Maahn F. Hoffmann M. D. Shupe G. de Boer S. Y. Matrosov E. P. Luke |
author_sort |
M. Maahn |
title |
Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
title_short |
Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
title_full |
Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
title_fullStr |
Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
title_full_unstemmed |
Can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
title_sort |
can liquid cloud microphysical processes be used for vertically pointing cloud radar calibration? |
publisher |
Copernicus Publications |
publishDate |
2019 |
url |
https://doi.org/10.5194/amt-12-3151-2019 https://doaj.org/article/32f3a5ab115141a0b0e8e51379327686 |
genre |
north slope Alaska |
genre_facet |
north slope Alaska |
op_source |
Atmospheric Measurement Techniques, Vol 12, Pp 3151-3171 (2019) |
op_relation |
https://www.atmos-meas-tech.net/12/3151/2019/amt-12-3151-2019.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-12-3151-2019 1867-1381 1867-8548 https://doaj.org/article/32f3a5ab115141a0b0e8e51379327686 |
op_doi |
https://doi.org/10.5194/amt-12-3151-2019 |
container_title |
Atmospheric Measurement Techniques |
container_volume |
12 |
container_issue |
6 |
container_start_page |
3151 |
op_container_end_page |
3171 |
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1766141136635691008 |