the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 28 Jul 2025
Analysis of a saline dust storm from the Aralkum Desert – Part 2: Atmospheric flow precursors in the Euro-Atlantic region
Abstract. Wind-blown dust emissions from the man-made Aralkum Desert pose significant environment and human health risks across Central Asia. Yet, little is known about the atmospheric circulation patterns favoring dust outbreaks from the region. This study examines the role of upstream atmospheric blocking and recurrent transient Rossby wave packets (RWPs) in initiating a severe dust storm from the Aralkum Desert in May 2018. Results show that the dust event was triggered by an unusual early-summer cold air outbreak and attendant postfrontal northerly winds reaching 24–31 m/s. The compound cold air and dust outbreaks were preceded by repeated meridional flow amplification linked to recurrent RWPs across the North Atlantic, persistent blocking over Scandinavia, and the subsequent development of a pronounced ridge-trough couplet that facilitated cold intrusions into Kazakhstan. This study underscores the importance of Euro-Atlantic blocking systems in shaping surface weather hazards in the downstream Central Asia region.
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Status: open (until 05 Oct 2025)
- RC1: 'Comment on egusphere-2025-2808', Anonymous Referee #1, 21 Aug 2025 reply
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RC2: 'Comment on egusphere-2025-2808', Anonymous Referee #2, 17 Sep 2025
reply
This is a rather short, follow-up paper, which complements previous publications from the same author (i.e. Xi, 2023; Xi et al., 2025) regarding an intense dust storm occurring in Central Asia (Aralkum Desert). The present study examines this dust event exclusively from the meteorological field of view, and more specifically it analyses the role of upstream atmospheric blocking and recurrent transient Rossby wave packets (RWPs) in initiating this severe dust storm. ERA5 reanalysis products and surface synoptic observations were synergistically used in this paper.
Although being a short and only meteorology-related paper, the main innovation of this study is that it underscores the importance of Euro-Atlantic blocking systems in shaping surface weather hazards in the Central Asia region. The organization of the material and the discussions of the large-scale meteorological systems are in good quality, while figures and results are clear and robust. Overall, the paper could be a good contribution to the journal (regarding the large-scale meteorological patterns associated with frontal dust storms in Central Asia) after some modifications, focusing mainly on improving the scientific background and the prevailing meteorological field over Central Asia.
In this respect, there are several studies that examine the large-scale atmospheric flow patterns and the long-term climatology of them over Central Asia as precursors for saline dust storms originating from the Aralkum Desert and from other deserts in the region. Regarding the synoptic or large-scale atmospheric circulation patterns that prevail over central Asia and are responsible for distribution, deposition, large-scale transportation of dust and formation of loess, recent works have provided important insights on this issue (Li et al., 2021, https://doi.org/10.1016/j.gsf.2021.101180; Li et al. 2022, https://doi.org/10.1016/j.gr.2022.04.019; Li et al. 2024, https://doi.org/10.1016/j.geomorph.2024.109461).
An intense dust-storm event occurring in central Asia, which was also strongly associated with blocking systems, was documented by Broomandi et al. (2021, https://doi.org/10.4209/aaqr.220309). The atmospheric circulation types over central Asia in that event present general similarities with the current case, mainly regarding the strong frontal system that caused the dust storm. Furthermore, Tositti et al. (2022, https://doi.org/10.5194/acp-22-4047-2022) examined the meteorological fields during a rare intense dust storm from Central Asia that affected northern Italy. For central Asian dust storms, the Capsian Sea High plays a major role (Kaskaoutis et al., 2017; DOI: 10.1002/joc.5053), regarding the frequency and intensity of the emissions, which may be also checked in this paper.
Since dust storms originated from the Aralkum Desert may have different directions (toward the south, east or even west to Europe), authors may provide useful insights about the direction, intensity or duration of the current dust storm in the abstract.
Lines 184-186. This dust storm over Uzbekistan was not examined in the current research. That dust storm was the subject of a previous study (Broomandi et al., 2023, AAQR). This is not a conclusion from the present study and should be placed rather in Introduction section and not in the conclusions.
Citation: https://doi.org/10.5194/egusphere-2025-2808-RC2
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This manuscript describes the synoptic evolution leading to a significant dust storm. However, it fails to provide a novel, rigorous, and causal analysis of the large-scale precursors. The study does not move beyond a plausible description of correlated events to deliver the promised insight into "dynamic teleconnections." The central issue is the lack of a demonstrable causal link between the identified Euro-Atlantic blocking/Rossby wave packets (RWPs) and the specific dust event in question. The analysis presents a plausible correlation but fails to establish a robust dynamical narrative, relying heavily on circumstantial evidence and subjective interpretation of standard reanalysis products. The methodological approach is insufficient to support the broad conclusions drawn. A fundamental revision would be required, involving a more sophisticated dynamical analysis to quantitatively link the upstream wave activity to the downstream response. However, given the scope of the required changes, my recommendation is to reject the current manuscript.
Specific Comments
1. Lack of Novelty and Incremental Insight:
The finding that Scandinavian blocking can lead to cold air outbreaks (CAOs) in Central Asia is well-established in the literature (e.g., Tyrlis and Hoskins, 2008; Tuel and Martius, 2024, both cited by the author). This manuscript merely applies this known mechanism to a specific case study without adding substantial new understanding. The analysis does not go significantly beyond a standard synoptic case study description using ERA5 data.
The claim of investigating "dynamic teleconnections" is overstated. The study describes a sequence of events but does not employ any diagnostic tools (e.g., potential vorticity tendency analysis, ray tracing, sensitivity experiments) to rigorously trace the energy propagation or causality from the North Atlantic RWPs to the downstream trough development in a quantifiable way.
2. Methodological Deficiencies in Establishing Causality:
The detection of recurrent RWPs using the Hovmöller-based R metric is interesting. However, the manuscript does not adequately demonstrate that these specific wave packets were responsible for the blocking onset or amplification. The statement that "RWPs may have served as precursors" is highly speculative and not backed by any causal analysis. The temporal sequence shown in Fig. 5a could easily be coincidental rather than causal.
The analysis of the warm conveyor belt (WCB) and its role is superficial. The authors point out its presence and potential importance but fail to quantify its diabatic contribution to downstream ridge building (e.g., through PV modification budgets or trajectory analysis), which is crucial for the claimed mechanism (Pfahl et al., 2015).
3. Inconsistent and Speculative Narrative:
The manuscript attempts to link too many phenomena (North Atlantic RWPs, Scandinavian blocking, a cyclone near Greenland, a WCB, wave breaking in the Barents Sea) into a single causal chain for one dust event. The narrative becomes speculative, especially when claiming that events in the North Pacific ("Recurrent transient RWPs are also observed over the North Pacific...") are part of the story without presenting any analysis to support a physical connection to the Euro-Atlantic sector or Central Asia. This weakens the focus and gives the impression of "hand-waving."
4. Questionable Framing as a "Companion Study":
The manuscript is presented as "Part 2" of a comprehensive investigation, with "Part 1" (Xi et al., 2025) focusing on satellite aerosol products. However, the two parts are entirely disconnected. There is no integration of the aerosol findings from Part 1 (e.g., the extreme AOD values, retrieval challenges) into the dynamical analysis presented here. The dust storm itself is treated only as a symptom of the meteorology, and the "saline" aspect mentioned in the title is never discussed in the context of the atmospheric dynamics. This represents a missed opportunity for a truly interdisciplinary study and makes the "companion" framing seem forced.
5. The definition of a "dusty day" based on SYNOP reports, which includes haze reports following dust within 48 hours, seems overly broad and could inflate the number of events used for the climatological comparison in Fig. 3b.