the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 15 May 2025
First insights into deep convection by the Doppler velocity measurements of the EarthCARE's Cloud Profiling Radar
Abstract. Convective updrafts and downdrafts play a vital role in Earth's energy and water cycles by modulating vertical energy and moisture transport and shaping precipitation patterns. Despite their importance, the characteristics of convective motions and their relationship to the near-storm environment remain poorly constrained by observations.
The payload of the recently launched EarthCARE satellite mission includes a 94-GHz Cloud Profiling Radar (CPR) with Doppler capability. In this study, we present first-light CPR Doppler velocity observations in deep convective clouds. These early examples offer a first glimpse into the dynamic nature of cloud systems. The narrow footprint of the CPR helps reduce the impact of multiple scattering and non-uniform beam filling (NUBF) on the Doppler velocity measurements. However, the instrument's low Nyquist velocity presents a significant challenge for recovering the true Doppler velocity profiles in deep convective systems.
The CPR Doppler velocity observations are expected to challenge traditional methodologies for identifying deep convective cores, which typically rely on reflectivity-based thresholds. We showcase examples that demonstrate the synergy between CPR Doppler velocity measurements and geostationary satellite observations, illustrating how their combined use can help capture the evolution of the convective lifecycle.
These results align with EarthCARE's broader mission objectives and highlight the potential of spaceborne Doppler radar to significantly advance our understanding of cloud dynamics and convection in the climate system.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Measurement Techniques.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.- Preprint
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RC1: 'Comment on egusphere-2025-1914', Anonymous Referee #1, 12 Jun 2025
This article describes an analysis of convective events as observed by the radar of the ESA/JAXA EarthCARE mission. This radar uses a novel technology in space, which is its Doppler capability. The authors do a great job of
1) illustrating the quality of the EarthCARE observations and
2) tying radar observations to underlying atmospheric dynamics.
The Authors' expertise allows them to juggle between data products and select the most appropriate to analyze various aspects of convection.
The task at hand is challenging because vigorous convection often means significant attenuation, large velocities that are aliased, multiple-scattering etc., especially at millimeter wavelengths like the one of EarthCARE's radar.I suggest major revisions of the article before it can be published. This is motivated by the fact that
- the article is quite long (Section 2 should be subdivided and unnecessary material should be left out).
- there is some work needed in terms of editing to avoid distracting the reader from the main message of your article (such distractions are unfortunate because you obviously did a lot of good work!).
For instance Lines 204-224 are really well written. Could you maintain that standard throughout the article, or have that co-author re-read the article?While I appreciate your use of radar and GEO data, I would recommend also using reanalysis data from ECMWF. In particular, it would be interesting to see if the height of the 0C isotherm is consistent with the melting layer that you observe, and if the ERA5 vertical wind has any updraft.
Also, I would suggest combining Figs 7 & 8: they are great but having to flip back and forth between them was yet another distraction from the precious scientific content of your article.
Lastly, this is just a convention, but could you please consider showing downward motion as negative velocities? That prevents mental exercises to interpret the Doppler observations.
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AC1: 'Reply on RC1', Aida Galfione, 17 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1914/egusphere-2025-1914-AC1-supplement.pdf
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RC3: 'Reply on AC1', Anonymous Referee #1, 17 Jun 2025
Dear Authors,
I have taken note of your initial reaction to my review (i.e. suggestions you agree with and those you disagree with). However, I would like to invite you to please consider
1) points that are also made by the second reviewer (e.g. regarding the convention for the sign of velocities, which is an easy fix);
And
2) more importantly, the PDF I attached which details the corrections and edits that I invite you to apply (I only see your reaction to the paragraph posted online, which is only one of many suggested corrections from your title to your references).
Respectfully,
Citation: https://doi.org/10.5194/egusphere-2025-1914-RC3 -
AC3: 'Reply on RC3', Aida Galfione, 20 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1914/egusphere-2025-1914-AC3-supplement.pdf
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AC3: 'Reply on RC3', Aida Galfione, 20 Jun 2025
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RC3: 'Reply on AC1', Anonymous Referee #1, 17 Jun 2025
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AC1: 'Reply on RC1', Aida Galfione, 17 Jun 2025
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RC2: 'Comment on egusphere-2025-1914', Anonymous Referee #2, 16 Jun 2025
This manuscript describes initial Doppler velocity measurements made by the EarthCARE Cloud Profiling Radar. These initial measurements are exciting and are the initial “pay back” for years of analysis and feasibility studies this team has made exploring the challenges of making Doppler velocity measurements from space. This manuscript is appropriate for Atmospheric Measurement Techniques and will need some minor changes before being ready for publication.
General Comments.
This reviewer’s comments are aimed at clarifying text that could be confusing to the reader. In general, the manuscript is well written. However, there are a couple paragraphs in the middle of the manuscript that are not of the same quality as the rest of the manuscript and will need editing and clarification (details are described below). One concern in these paragraphs is the inclusion and analysis of Doppler velocity estimates in the regions below multiple scattering, which, I believe, should not have valid atmospheric observations.
Specific Comments.
- Line 74. Please correct satellite speed (7.6 km/s).
- Line 99 and Fig. 1a. Please clarify for the reader whether the spatial resolution of the reflectivity measurements shown in Fig. 1a is at 500-m, 4-km, or some other spatial resolution.
- Line 102. Please clarify for the reader, is the averaging immune to velocity folding, or is the lag-1 velocity estimator immune to velocity folding? Or, is this statement even necessary?
- Line 122. Please inform the reader the value of the Pulse Repetition Frequency and the Nyquist velocity for the examples shown in the manuscript.
- Line 126. Please inform the reader that this estimated maximum value of 6.5 m/s is obtained only when using a radar operating at W-band and that larger reflectivity-weighted mean velocities are measured when using radars operating at lower frequencies. (Readers may be more familiar with Ka-, Ku-, or X-band airborne radars; or Ka-, K-, C-, or S-band ground based radars.)
- Line 136. The phrase 'requires knowledge' is the incorrect phrase to use here because we will never “know” the exact Doppler terminal fall speed (aka, reflectivity-weighted mean fall speed) of the hydrometeors within the radar resolution volume. This sentence is shifting from observations to a retrieval algorithm, so a more appropriate phrase to use here is 'requires parameterization', or some other expression that reflects that the Doppler terminal fall speed is not measured.
- Line 136. Please clarify the text. As written, the phrase "...VT^D can be…" is equivalent to the phrase "...it could be done, but was not done in this study".
- Line 135-137. After reviewing comments #6 and #7, maybe the discussion of retrieving air motion will be confusing to the reader because air motion is not retrieved in this manuscript. Possibly, the sentences from lines 135 to 137 can be deleted.
- Lines 143 to 188. The paragraphs from line 143 through 188 are not of the same quality as other paragraphs in this manuscript. These paragraphs contain grammar errors, errors in logic, and a change in variable notation. These paragraphs need to be rewritten and then proof-read for consistency with the rest of the manuscript. A couple major concerns (and not all concerns) include:
- Line 170, the text is, “…VD is positive indicating the presence of an updraft.” This is inconsistent with Equation (1) that defines positive values as downward motion.
- Figures 4 and 5. The variable VSED is shown in Fig. 4 and 5, but it is not described in the body. Also, is VSED the same as VT^D?
- Line 185, Fig. 4b and 4c below 11 km, and Fig. 5b and 5c below 14 km. Are the authors suggesting that the Doppler velocity measurements below the reflectivity ‘knee” corresponding to the height region below multiple scattering are valid and represent atmospheric observations? The authors will need to describe how the change in phase of signals coming from non-radial directions are representative of motions along the radial direction.
- Lines 257 to 259 and Figure 8. Where are the green bars in Fig. 8a?
- Figure 8. What are the symbols in Fig. 8a and 8b?
- Figure 8. Can you please label Cell 1 and Cell 2 in the figure to help follow the discussion in the text?
- Line 316, the phrase “…unprecedented view of convective motions on a global scale” is incorrect and very misleading. The satellite makes nadir measurements and is in an orbit around the globe. These measurements are not at a “global scale”. Also, this work shows images of a few individual precipitation events that do not represent motions on the global scale. Therefore, the phrase can be reduced to, “…unprecedented view of convective motions.”
Citation: https://doi.org/10.5194/egusphere-2025-1914-RC2 -
AC2: 'Reply on RC2', Aida Galfione, 20 Jun 2025
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-1914/egusphere-2025-1914-AC2-supplement.pdf
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