the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 12 Feb 2024
Technical note: Retrieval of the supercooled liquid fraction in mixed-phase clouds from Himawari-8 observations
Abstract. The supercooled liquid fraction (SLF) in mixed-phase clouds (MPCs) is an essential variable of cloud microphysical processes and climate sensitivity. However, SLF is currently calculated in spaceborne remote sensing only as the cloud phase frequency ratio of adjacent pixels, which results in a loss of the original resolution in observations of cloud liquid or ice content within MPCs. Here, we present a novel method for retrieving the SLF in MPCs based on the differences in radiative properties of supercooled liquid droplets and ice particles at visible and shortwave‐infrared channels of the geostationary Himawari-8. Liquid and ice water paths are inferred by assuming that clouds are composed of only liquid or ice, with the real cloud water path (CWP) expressed as a combination of these two water paths (SLF and 1-SLF as coefficients), and SLF is determined by referring to the CWP from CALIPSO. The statistical relatively small cloud phase spatial inhomogeneity in Himawari-8-pixel level indicates an optimal scene for the cloud retrieval. The SLF results are comparable to global SLF distributions observed by active instruments, particularly for single-layered cloud systems. While accessing the method’s feasibility, SLF averages are estimated between 74 % and 78 % in Southern Ocean stratocumulus across seasons, contrasting with a range of 29 % to 32 % in Northeast Asia. The former exhibits a minimum SLF around midday in summer and a maximum in winter, while the latter trend differs. This novel algorithm will be valuable for research to track the evolution of MPCs and constrain the related climate impact.
-
Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
-
Preprint
(1759 KB)
-
Supplement
(667 KB)
-
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1759 KB) - Metadata XML
-
Supplement
(667 KB) - BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2023-2667', Anonymous Referee #1, 27 Feb 2024
This paper presents a novel method for retrieving the supercooled liquid fraction (SLF) of mixed-phase clouds using observations from the geostationary Himawari-8 satellite. By using differences in radiative properties between cloud droplets and ice particles, the method explores the extreme states of clouds, whether fully supercooled or fully glaciated, and reference cloud water content data from CALIPSO are incorporated. The uncertainties of the method are evaluated. Furthermore, the method's accuracy is assessed using various datasets, and its feasibility is thoroughly discussed through applications of analyzing the diurnal cycle of SLF and considering hemispheric contrasts. As a "Technical Note," this paper provides distinctly valuable insights into the further evolution and climate impact of mixed-phase clouds. I recommend its publication in ACP, with some minor comments provided for the authors' consideration, acknowledging the well done work accomplished in this article.
Comments:
Introduction: In discussing research on SLF, it is good to include airborne measurements as well, for example, Wang et al. (2023).
Yang Wang et al.: High small ice concentration in stratiform clouds over Eastern China based on aircraft observations: Habit properties and potential roles of secondary ice production, Atmospheric Research, 281,106495, 2023.
Figure 3: Can you imply the relationship between the retrieved SLF and the CWPprediction?
Line 251-253: “…the cloud phase spatial inhomogeneity is scarcely shown in the Himawari-8-pixel level (5km)”. Are you assuming that the clouds within the Himawari-8-pixel level are composed of either liquid droplets or ice particles? This statement may lead to misunderstanding. Could you elaborate further on the implications of cloud phase inhomogeneity in Himawari-8 (5km) from CALIPSO data (333m)?
Line 270-274: Would it be better to add a scattering plot or another format of quantitative comparison of “SLF_CALIPSO_GOCCP” and “SLF_Himawari-8” for Figure 6?
Technical comments:
L16: “statistically” instead of “statistical”?
L25: Singular verb “forms” should be used here.
L141: Plural verb “appear”.
L146: “analyzed” instead of “analyze”.
L202: “varies” instead of “vary”.
L316: with an average “of” around 74%...
L329: remove “around”.
Citation: https://doi.org/10.5194/egusphere-2023-2667-RC1 -
RC2: 'Comment on egusphere-2023-2667', Anonymous Referee #2, 03 Mar 2024
The authors present a method for obtaining the mass phase ratio (MPR) of clouds in the mixed phase temperature regime from the Himawari-8 satellite. They compare this method with CALIPSO-GOCCP and show good first results. The method is novel and timely, and this technical note is worthy of publication. However, a weakness of the evaluation is that there are no comparisons between SLF and temperature, which makes it difficult to assess the quality of the results. Nevertheless, as a technical note focusing on the novelty of the method, I support the publication of the paper in ACP.
# Some minor suggestions:
Line 108: This would be clearer if the sentence were split into two sentences explaining input and output.
Line 130: Please check the trailing "IF" at the end.
Line 209: Ice-dominant -> Ice-dominated. belt -> belts
Line 210: Which invalid cases are excluded? Phase-overlap scenes, ice-dominant MPCs or WCBs and convection? How are these cases defined? Please clarify
Citation: https://doi.org/10.5194/egusphere-2023-2667-RC2 - AC1: 'Authors' Comment (AC) on egusphere-2023-2667', Ziming Wang, 20 Apr 2024
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2023-2667', Anonymous Referee #1, 27 Feb 2024
This paper presents a novel method for retrieving the supercooled liquid fraction (SLF) of mixed-phase clouds using observations from the geostationary Himawari-8 satellite. By using differences in radiative properties between cloud droplets and ice particles, the method explores the extreme states of clouds, whether fully supercooled or fully glaciated, and reference cloud water content data from CALIPSO are incorporated. The uncertainties of the method are evaluated. Furthermore, the method's accuracy is assessed using various datasets, and its feasibility is thoroughly discussed through applications of analyzing the diurnal cycle of SLF and considering hemispheric contrasts. As a "Technical Note," this paper provides distinctly valuable insights into the further evolution and climate impact of mixed-phase clouds. I recommend its publication in ACP, with some minor comments provided for the authors' consideration, acknowledging the well done work accomplished in this article.
Comments:
Introduction: In discussing research on SLF, it is good to include airborne measurements as well, for example, Wang et al. (2023).
Yang Wang et al.: High small ice concentration in stratiform clouds over Eastern China based on aircraft observations: Habit properties and potential roles of secondary ice production, Atmospheric Research, 281,106495, 2023.
Figure 3: Can you imply the relationship between the retrieved SLF and the CWPprediction?
Line 251-253: “…the cloud phase spatial inhomogeneity is scarcely shown in the Himawari-8-pixel level (5km)”. Are you assuming that the clouds within the Himawari-8-pixel level are composed of either liquid droplets or ice particles? This statement may lead to misunderstanding. Could you elaborate further on the implications of cloud phase inhomogeneity in Himawari-8 (5km) from CALIPSO data (333m)?
Line 270-274: Would it be better to add a scattering plot or another format of quantitative comparison of “SLF_CALIPSO_GOCCP” and “SLF_Himawari-8” for Figure 6?
Technical comments:
L16: “statistically” instead of “statistical”?
L25: Singular verb “forms” should be used here.
L141: Plural verb “appear”.
L146: “analyzed” instead of “analyze”.
L202: “varies” instead of “vary”.
L316: with an average “of” around 74%...
L329: remove “around”.
Citation: https://doi.org/10.5194/egusphere-2023-2667-RC1 -
RC2: 'Comment on egusphere-2023-2667', Anonymous Referee #2, 03 Mar 2024
The authors present a method for obtaining the mass phase ratio (MPR) of clouds in the mixed phase temperature regime from the Himawari-8 satellite. They compare this method with CALIPSO-GOCCP and show good first results. The method is novel and timely, and this technical note is worthy of publication. However, a weakness of the evaluation is that there are no comparisons between SLF and temperature, which makes it difficult to assess the quality of the results. Nevertheless, as a technical note focusing on the novelty of the method, I support the publication of the paper in ACP.
# Some minor suggestions:
Line 108: This would be clearer if the sentence were split into two sentences explaining input and output.
Line 130: Please check the trailing "IF" at the end.
Line 209: Ice-dominant -> Ice-dominated. belt -> belts
Line 210: Which invalid cases are excluded? Phase-overlap scenes, ice-dominant MPCs or WCBs and convection? How are these cases defined? Please clarify
Citation: https://doi.org/10.5194/egusphere-2023-2667-RC2 - AC1: 'Authors' Comment (AC) on egusphere-2023-2667', Ziming Wang, 20 Apr 2024
Peer review completion
Journal article(s) based on this preprint
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 444 | 94 | 24 | 562 | 41 | 12 | 16 |
- HTML: 444
- PDF: 94
- XML: 24
- Total: 562
- Supplement: 41
- BibTeX: 12
- EndNote: 16
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
Husi Letu
Huazhe Shang
Luca Bugliaro
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(1759 KB) - Metadata XML
-
Supplement
(667 KB) - BibTeX
- EndNote
- Final revised paper