the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 22 Jul 2026
Overhaul of the stratospheric lidar at Dumont d’Urville, Antarctica: three-wavelength setup, processing and observations
Abstract. The stratospheric cloud and aerosol lidar instrument Liraan (LIdar pour la Recherche Antarctique Aérosol et Nuages) has been operated at the French Antarctic station Dumont d'Urville since 1989. Following a major upgrade conducted between 2022 and 2024, this paper presents the instrument configuration and its scientific capabilities. Liraan now enables the retrieval of backscatter coefficients at 355 nm, 532 nm and 1064 nm and depolarization ratios at 355 nm and 532 nm. The new configuration is described in detail, along with an improved data inversion algorithm, which is further used as input to a dedicated microphysical retrieval methodology. A unified 532 nm lidar time series spanning 1991–2025 at Dumont d'Urville is also presented for the first time. Finally, 2025 multispectral lidar measurements are used in a case study of volcanic aerosol size distribution retrieval.
- Preprint
(5880 KB) - Metadata XML
- BibTeX
- EndNote
Status: final response (author comments only)
- RC1: 'Comment on egusphere-2026-2958', Anonymous Referee #1, 19 Aug 2026
-
RC2: 'Comment on egusphere-2026-2958', Anonymous Referee #2, 24 Aug 2026
General comments
This preprint presents the current technical configuration and data processing procedures of the stratospheric lidar operated at Dumont d’Urville (Antarctica). This instrument has been operating since 1989 in a particularly remote region, under harsh meteorological conditions and with major logistical constraints. Long-term observations of this type are of great importance for the scientific community, in particular for monitoring the Antarctic stratosphere and documenting the occurrence and evolution of stratospheric aerosol and polar stratospheric cloud events.
In this context, I consider it very valuable that the current technical configuration of the instrument, as well as the associated data processing and inversion procedures, are comprehensively documented and made available to the community. Such documentation is particularly important for long-term observational infrastructures, where successive technical developments and changes in instrumentation need to be properly documented to ensure the long-term usability and interpretation of the data.
Overall, I find the manuscript well motivated and generally well presented. I am therefore in favor of publication in AMT, after the comments and questions raised below are addressed in a revised version.
Specific comments
1) Line 20, the sentence “Similar systems have since been installed in McMurdo, Rothera and Davis stations (Adriani et al., 1992, 2004; Innis and Klekociuk, 2006; Simpson et al., 2005), with some instruments relocated between stations to maintain operations (Snels et al., 2019, 2021; Cairo et al., 2023).” is not entirely clear to me. It is not clear to me what is meant by “some instruments relocated between stations”?
2) The introduction provides a good description of the scientific motivation and historical context of the Dumont d’Urville lidar, and link with satellite missions (CALIPSO/EARTHCARE). However, I think that the organisational and networking context could be described in greater detail.
The Data availability section (line 425) indicates that the instrument operates within the framework of NDACC. I suggest that this should also be introduced earlier in the Introduction. In particular, it would be useful to explain what operating within NDACC implies for the observations presented in this paper, for example in terms of quality assurance and quality control, data processing procedures, calibration, and/or harmonisation of the products with observations from other NDACC lidar stations.
This information would also help the reader to better understand the role of the Dumont d’Urville lidar within the broader international network and the extent to which the processing described in the manuscript follows established NDACC recommendations or procedures specific to this instrument.
3) The data-processing section is clearly presented and provides useful information on the inversion procedures and uncertainty propagation. However, I would appreciate some additional information concerning the status and origin of the inversion and error-propagation codes.
Are these codes research codes specifically developed by the authors for the Dumont d’Urville lidar? Or are they community-developed codes that are also used for other similar or related lidar instruments?
If the codes are based on existing community tools, it would be useful to provide the relevant references and to explain which parts have been specifically adapted or developed for the Dumont d’Urville system. Conversely, if the codes have been developed specifically for this instrument, could the authors indicate whether they are available to the scientific community, for example through an open-source repository?
Given the long-term importance of the dataset and the increasing emphasis on reproducibility of measurement processing, information on the accessibility and reusability of these codes would significantly strengthen the manuscript.
Technical corrections
1) Figure 1
The small text and labels in Figure 1 are readable in the digital version when zooming to 300%, but they are too small to be comfortably read in a printed version.
I suggest either increasing the font size or, preferably, removing the detailed textual information from the schematic and reporting these details in one or more tables. This would make the figure easier to read and would improve its usefulness in both electronic and printed versions.
2) Figure 3
The positioning of the years on the x-axis appears irregular. For example, the distance between 2004 and 2005 is smaller than that between 2005 and 2006. This makes it difficult to accurately identify the dates corresponding to the beginning and end of the episodes indicated by the white brackets.
This can be problematic when the figure is used to relate the observed lidar signatures to known events. For example, the Calbuco eruption occurred in April 2015, whereas the current positioning of the time series gives the impression that the corresponding signatures may start as early as autumn 2014.Citation: https://doi.org/10.5194/egusphere-2026-2958-RC2
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 155 | 31 | 13 | 199 | 18 | 29 |
- HTML: 155
- PDF: 31
- XML: 13
- Total: 199
- BibTeX: 18
- EndNote: 29
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
The manuscript entitled “Overhaul of the stratospheric lidar at Dumont d’Urville, Antarctica: three-wavelength setup, processing and observations” by Tence et al. presents a substantial upgrade of the stratospheric lidar at Dumont d’Urville, including the implementation of a three-wavelength configuration and new approaches for data processing and analysis. The enhanced capabilities of the lidar are particularly relevant for future studies of stratospheric aerosols and polar stratospheric clouds (PSCs).
Overall, the manuscript is well structured, scientifically relevant, and well suited for publication in Atmospheric Measurement Techniques. However, I believe that the manuscript would benefit from a more comprehensive demonstration of the capabilities offered by the new three-wavelength configuration. I therefore recommend that the authors address the following major point:
The manuscript would benefit from additional examples demonstrating the scientific benefit of this new configuration. At present, the full potential of the three-wavelength measurements is not sufficiently illustrated.
According to the authors, the upgraded lidar is particularly well suited for observations of polar stratospheric clouds and aerosol-perturbed stratospheric conditions. In this context, I strongly encourage the authors to include an example of a PSC observation obtained with the new lidar system. Ideally, this example could also demonstrate how the available measurements can be used to distinguish or classify different PSC types. Such an example would provide a valuable demonstration of the capabilities of the upgraded system and would strengthen the relevance of the manuscript for future PSC studies.
Minor points
Section 3.1 Pre-processing steps are not clear and further explanation are needed. For example, how is the transmission factor CO3, λ later used in the lidar signal Pλ. Further, for what do you use the total lidar signal?
Line 219 to 225: It is not clear how znc is used to optimise zref.
Figure 3: Could you add within the text what altitude range is shown in the plot?
Line 347: The Ruang plume is not decreasing smoothly in Figure 4, there are “jumps” of around 4km between different observations times (e.g. before 1st of April). I am somewhat surprised by the large variability observed within the stratospheric layer attributed to volcanic plume. Considering the remote location of Dumont d’Urville and the transport time required for volcanic material to reach the Antarctic stratosphere, I would have expected the volcanic plum to be relatively well aged and spatially dispersed by the time it is observed over the station. Could the authors provide some discussion of the processes that may explain the pronounced variability observed in this layer?