Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models
<p>Currently, terahertz remote sensing technology is one of the best ways to detect the microphysical properties of ice clouds. Influenced by the representativeness of the ice crystal scattering (ICS) model, the existing terahertz ice cloud remote sensing inversion algorithms still have signif...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-01-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/331/2023/amt-16-331-2023.pdf |
| _version_ | 1797944901151752192 |
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| author | M. Li M. Li H. Letu H. Ishimoto S. Li L. Liu T. Y. Nakajima D. Ji H. Shang C. Shi |
| author_facet | M. Li M. Li H. Letu H. Ishimoto S. Li L. Liu T. Y. Nakajima D. Ji H. Shang C. Shi |
| author_sort | M. Li |
| collection | DOAJ |
| description | <p>Currently, terahertz remote sensing technology is one of
the best ways to detect the microphysical properties of ice clouds.
Influenced by the representativeness of the ice crystal scattering (ICS)
model, the existing terahertz ice cloud remote sensing inversion algorithms
still have significant uncertainties. In this study, based on the Voronoi
ICS model, we developed a terahertz remote sensing inversion algorithm of
the ice water path (IWP) and median mass diameter (<span class="inline-formula"><i>D</i><sub>me</sub></span>) of ice clouds.
This study utilized the single-scattering properties (extinction efficiency,
single-scattering albedo, and asymmetry factor) of the Voronoi, sphere, and
hexagonal column ICS models in the terahertz region. Combined with 14 408
groups of particle size distributions obtained from aircraft-based
measurements, we developed the Voronoi, sphere, and column ICS schemes based
on the Voronoi, sphere, and column ICS models. The three schemes were applied
to the radiative transfer model to carry out the sensitivity analysis
of the top-of-cloud (TOC) terahertz brightness temperature differences
between cloudy and clear skies (BTDs) on the IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span>. The
sensitivity results showed that the TOC BTDs between 640 and 874 GHz are
functions of the IWP, and the TOC BTDs of 380, 640, and 874 GHz are
functions of the <span class="inline-formula"><i>D</i><sub>me</sub></span>. The Voronoi ICS scheme possesses stronger
sensitivity to the <span class="inline-formula"><i>D</i><sub>me</sub></span> than the sphere and column ICS schemes. Based on
the sensitivity results, we built a multi-channel look-up table for BTDs.
The IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span> were searched from the look-up table using an optimal
estimation algorithm. We used 2000 BTD test data randomly generated by the
RSTAR model to assess the algorithm's accuracy. Test results showed that the
correlation coefficients of the retrieved IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span> reached 0.99 and
0.98, respectively. As an application, we used the inversion algorithm to
retrieve the ice cloud IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span> based on the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) airborne
terahertz radiation measurements. Validation against the retrievals of the
Bayesian algorithm reveals that the Voronoi ICS model performs better than
the sphere and hexagonal column ICS models, with enhancement of the mean
absolute errors of 5.0 % and 12.8 % for IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span>, respectively.
In summary, the results of this study confirmed the practicality and
effectiveness of the Voronoi ICS model in the terahertz remote sensing
inversion of ice cloud microphysical properties.</p> |
| first_indexed | 2024-04-10T20:46:56Z |
| format | Article |
| id | doaj.art-61587ca18f6d412c8d9e9d906e9f036b |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-10T20:46:56Z |
| publishDate | 2023-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-61587ca18f6d412c8d9e9d906e9f036b2023-01-24T07:19:11ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482023-01-011633135310.5194/amt-16-331-2023Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering modelsM. Li0M. Li1H. Letu2H. Ishimoto3S. Li4L. Liu5T. Y. Nakajima6D. Ji7H. Shang8C. Shi9State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100101, ChinaUniversity of Chinese Academy of Sciences, Beijing, 100049, ChinaState Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100101, ChinaMeteorological Research Institute, Japan Meteorological Agency (JMA), Nagamine 1-1, Tsukuba, 305-0052, JapanCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha, 410073, ChinaCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha, 410073, ChinaResearch and Information Center (TRIC), Tokai University, 4-1-1 Kitakaname Hiratsuka, Kanagawa, 259-1292, JapanState Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100101, ChinaState Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100101, ChinaState Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, 100101, China<p>Currently, terahertz remote sensing technology is one of the best ways to detect the microphysical properties of ice clouds. Influenced by the representativeness of the ice crystal scattering (ICS) model, the existing terahertz ice cloud remote sensing inversion algorithms still have significant uncertainties. In this study, based on the Voronoi ICS model, we developed a terahertz remote sensing inversion algorithm of the ice water path (IWP) and median mass diameter (<span class="inline-formula"><i>D</i><sub>me</sub></span>) of ice clouds. This study utilized the single-scattering properties (extinction efficiency, single-scattering albedo, and asymmetry factor) of the Voronoi, sphere, and hexagonal column ICS models in the terahertz region. Combined with 14 408 groups of particle size distributions obtained from aircraft-based measurements, we developed the Voronoi, sphere, and column ICS schemes based on the Voronoi, sphere, and column ICS models. The three schemes were applied to the radiative transfer model to carry out the sensitivity analysis of the top-of-cloud (TOC) terahertz brightness temperature differences between cloudy and clear skies (BTDs) on the IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span>. The sensitivity results showed that the TOC BTDs between 640 and 874 GHz are functions of the IWP, and the TOC BTDs of 380, 640, and 874 GHz are functions of the <span class="inline-formula"><i>D</i><sub>me</sub></span>. The Voronoi ICS scheme possesses stronger sensitivity to the <span class="inline-formula"><i>D</i><sub>me</sub></span> than the sphere and column ICS schemes. Based on the sensitivity results, we built a multi-channel look-up table for BTDs. The IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span> were searched from the look-up table using an optimal estimation algorithm. We used 2000 BTD test data randomly generated by the RSTAR model to assess the algorithm's accuracy. Test results showed that the correlation coefficients of the retrieved IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span> reached 0.99 and 0.98, respectively. As an application, we used the inversion algorithm to retrieve the ice cloud IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span> based on the Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) airborne terahertz radiation measurements. Validation against the retrievals of the Bayesian algorithm reveals that the Voronoi ICS model performs better than the sphere and hexagonal column ICS models, with enhancement of the mean absolute errors of 5.0 % and 12.8 % for IWP and <span class="inline-formula"><i>D</i><sub>me</sub></span>, respectively. In summary, the results of this study confirmed the practicality and effectiveness of the Voronoi ICS model in the terahertz remote sensing inversion of ice cloud microphysical properties.</p>https://amt.copernicus.org/articles/16/331/2023/amt-16-331-2023.pdf |
| spellingShingle | M. Li M. Li H. Letu H. Ishimoto S. Li L. Liu T. Y. Nakajima D. Ji H. Shang C. Shi Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models Atmospheric Measurement Techniques |
| title | Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models |
| title_full | Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models |
| title_fullStr | Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models |
| title_full_unstemmed | Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models |
| title_short | Retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped Voronoi ice scattering models |
| title_sort | retrieval of terahertz ice cloud properties from airborne measurements based on the irregularly shaped voronoi ice scattering models |
| url | https://amt.copernicus.org/articles/16/331/2023/amt-16-331-2023.pdf |
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