the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 18 Aug 2025
Inter-annual snow accumulation and meter-scale variability from trench measurements at Dome C, Antarctica
Abstract. The central regions of the East Antarctic ice sheet contains some of the oldest ice on earth, due to low snow accumulation rates and consistently cold conditions. One consequence of low accumulation however is that the little snow amount which is deposited at irregular times is more strongly affected by erosion and re-deposition by wind, inducing local mixing and loss of snowfall events in the snowpack. This discontinuous deposition leads to highly disturbed snow layers, limiting the interpretation of climate records from ice cores in these regions to time scales larger than decades. In order to interpret climate records at higher temporal resolution it is crucial to assess and quantify the local patterns of snow accumulation leading to stratigraphic noise.
Here, we reconstruct the spatial and temporal variability of snow accumulation in Central Antarctica using chemical composition and physical properties in 35 vertical profiles sampled in a 50 m long snow trench at Dome C. We show that a high resolution alignment of the chemistry profiles is a suitable method for inter-annual dating of the single trench profiles, allowing the reconstruction of accumulation time series with a 1 year resolution over the last 20 years. This reconstruction shows annually-varying past surface configurations, with about 10 % of the surface subject to accumulation hiatus. More persistent patterns with timescales of years are also evidenced, causing difference in snow age of up to 4 years at similar depth in neighboring profiles, highlighting the complex dynamics of the snow accumulation in central Antarctica.
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Status: open (until 05 Oct 2025)
- RC1: 'Comment on egusphere-2025-3259', Anonymous Referee #1, 12 Sep 2025 reply
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- 1
Ooms et al. reconstructed the snow accumulation time series at Dome C over the last 20 years, using chemical composition and physical properties from 35 vertical profiles in a 50 m long snow trench. This is a rare, high-resolution multi-profile trench dataset from the Antarctic Plateau, providing a reference for subsequent SMB research. Their results showed that the annual SMB broadly agrees with stake farm and ERA5, exhibits meter-scale spatial variability, and reflects persistent meter-scale topographic features over multiyear timescales. I believe this work will interest researchers studying surface mass balance (SMB), stratigraphic processes, and ice core interpretation on the Antarctic Plateau. However, the manuscript needs more confirmation and clarification before acceptance.
Major comments:
1. The key result of this study is the establishment of a high-resolution dating method for snowpits. The dating is achieved by aligning the target profile with the sulfate records of old snowpits. The process of manually selecting tie points for alignment is subjective. The article does not quantify the agreement between different operators.
2. I believe that all readers will want to know why this study uses a single profile P0 as the reference to align all other sections in the entire 50-meter trench.
(1) If P0 itself is abnormal, then this anomaly may be passed on to all other profiles, causing a deviation in the dating of the entire. Münch et al. (2016, https://doi.org/10.5194/cp-12-1565-2016) pointed out it is necessary to average multiple ice cores or snowpits to extract climate signals and filter out stratigraphic noise.
(2) When P0 is compared with snowpits that may be hundreds of meters or even farther away, the basic assumption is that the sulfate signal is stable over a considerable spatial scale. However, an important finding of this study is that there is a significant meter-scale spatial variability in snow accumulation. Gautier et al. (2016, https://doi.org/10.5194/cp-12-103-2016) indicates that even ice cores just a few meters apart may have missing records of volcanic events.
(3) The manuscript indicates in the method section that due to too little snow was available to measure chemical elements of the P0 sample, it was mixed with a high-resolution sample from another profile. The authors did not explain the specific method of mixing, and this operation may artificially change the chemical signal of the reference profile.
So I am skeptical about using a single and mixed profile P0 as the reference for the age alignment of the 50 m trench.
3. The authors take the mid-2015 isochrone as an example to validate past topography. Using imperfect individual cases to prove isochrony over a twenty-year period is too weak. I suggest adding more isochrone for verification rather than relying on a single “perfect case”. For example, Sinnl et al. (2022，https://doi.org/10.5194/cp-18-1125-2022 ) emphasize the use of multiple time periods and various indicators to validate age model.
Minor comments:
1. The horizontal decorrelation length of the sulfate signal is 1.26 m in the aligned trench in L204. However, in Figure A6 of the appendix, the legend shows the aligned decorrelation length as “1.40 m”.
2. Only 6 dating points were kept for the age model in L144, but table 1 lists seven different records of snowpits/ice cores.
L24: “offsetted” should be “offset”
L38/57: unify spelling of “snowpit / snow pit”.
L73: Could you explain the direction of the dominant wind?
L78: remove height .
L81: “was” should be “were”.
Figure 1 caption it is more appropriate to change the + in Figure 1 to follow by.
Figure 1 caption: “1.5cm” should be “1.5 cm”.
L116: Could you tell me why you chose SSA > 40 as the threshold?
L175: Does this indicate that the previous use of 320 as the density value of Dome C is too high?
L487: “alignement” should be “alignment