the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 28 Jul 2026
Mongolian Cyclone Intensification Reshapes Dust Activity in Northwest China
Abstract. Dust storms are a common hazardous weather phenomenon in arid regions. In recent years, dust storm intensity in northwest China has increased markedly under changing atmospheric circulation conditions, yet the underlying mechanisms remain debated. Previous studies have largely attributed dust variability to land-surface changes and broad-scale circulation anomalies, but the spatially divergent responses of different dust source regions to circulation changes remain poorly understood. Here, we investigate Mongolian cyclone variability during 2001–2025 and its impacts on dust activity in the Taklimakan Desert, Alxa Plateau, and Mu Us Sandy Land using multi-source observational data and a random forest regression model. Results showed that (1) Mongolian cyclone intensity increased from 94.84 × 10-5 s-1 to 97.76 × 10-5 s-1 and shifted southward by about 2.08° after 2019; (2) Strengthened Mongolian cyclone activity enhanced dust emissions in the Alxa Plateau (from 0.23 to 0.28 g·m-2 since 2019), whereas dust activity declined in the Taklimakan Desert, which is less affected by Mongolian cyclone forcing (from 0.63 to 0.57 g·m-2 since 2019); (3) Wind was the dominant driver of dust activity (contribution >0.60), while precipitation and the Pressure Gradient Index (PGI) were important secondary contributors in the Alxa and Mu Us regions, and PGI partially modulated wind effects in surrounding cities; and (4) Regional spring mean PM10 concentrations are projected to increase substantially during 2026–2100 (229.98–824.31 μg·m-3) and show weak sensitivity to emission scenarios. These findings highlight the importance of explicitly considering cyclone-wind regime-topography interactions in future dust projections, as circulation-driven variability may play a larger role than previously recognized in regulating East Asian dust activity.
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Status: open (until 08 Sep 2026)
- RC1: 'Comment on egusphere-2026-3940', Anonymous Referee #1, 14 Aug 2026 reply
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CC1: 'Comment on egusphere-2026-3940', Guoming Zhang, 19 Aug 2026
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- General comments：
The manuscript investigates the spatially divergent effects of the intensification and southward shift of Mongolian cyclones on dust activity in northwest China. It uses ground-based PM₁₀ observations, MERRA-2, ERA5, MODIS, land-use, and CMIP6 data, with the multiple data sources providing mutual corroboration. Trend analysis, segmented regression, and random forest models are combined to compare the Taklimakan Desert, Alxa Plateau, and Mu Us Sandy Land. The topic is of practical significance. Overall, the research framework is generally sound, and the main results are reasonably clear. I recommend that the manuscript be considered for publication after minor revision.
The manuscript should be further focused on its central theme. In Section 3.1, the discussion of Arctic warming, Barents Sea ice, polar-vortex perturbations, and dust-radiative feedback extends beyond the processes directly analyzed in this study. The current wording may lead readers to interpret these mechanisms as findings derived from and validated by the present study. I recommend shortening this paragraph and clearly identifying these processes as possible background mechanisms proposed in the literature, or moving the paragraph to the end of the Discussion as a direction for future research.
Key methodological details should be added, particularly regarding the processing of multisource datasets. The manuscript does not adequately describe the criteria used to identify Mongolian cyclones, the methods used to determine cyclone centers and calculate cyclone intensity, the definition of the PGI, the source and basic attributes of the NOAA dust-storm-day data, or the procedures used to train and validate the random forest model.
- Specific comments:
Line 52: “The Alxa Plateau” and “the Mu Us Sandy Land” are two distinct geographical regions. The expression “the Alxa Plateau (including Mu Us Sandy Land)” may incorrectly imply that one encompasses the other, and the two regions are analyzed separately later in the manuscript. The wording should therefore be standardized as “the Alxa Plateau and the Mu Us Sandy Land.”
Line 69: This paragraph refers to the study period as the “past 45 years,” whereas the main dataset analyzed in the manuscript covers 2001-2025, a period of only 25 years. This should be corrected.
Lines 84-88: The description of the study area is too brief. The authors should provide the latitudinal and longitudinal extent of the study area, the boundaries of each subregion, the number of monitoring stations, and the criteria used for regional classification. These features could be clearly presented in a study-area map.
Lines 90-94: The ground-based PM₁₀ data cover 2016-2025, whereas the caption of Fig. 2C (Lines 229-231) states that the data cover 2001-2025. This is an obvious inconsistency and should be verified and corrected. The authors should also describe the treatment of missing station data, quality-control procedures, calculation of daily mean values, and criteria used to identify valid observation days.
Lines 181-185, 219-224, and 389-392: The Results describe the change in cyclone latitude as occurring “after 2020,” whereas the Abstract and Conclusions state “after 2019.” These expressions should be standardized. Alternatively, the authors should clarify that 2019 represents the statistical breakpoint, whereas 2020 marks the onset of the pronounced southward shift.
Fig. 5 and Lines 352-370: I recommend replacing the three-dimensional pie charts in panels A-C with two-dimensional charts, as the three-dimensional presentation is not effective. For panels D-F, the multi-model ensemble mean, model spread, or 95% confidence intervals should be provided. The figure caption should also clarify whether the vertical axis represents spring mean or annual mean PM₁₀ and whether the curves represent the three-model ensemble results.
Line 395: The precipitation threshold is reported as 144 mm in the Conclusions but as 143 mm in the main text (Line 284). These values should be made consistent.
- Technical corrections:
Line 443: “Inner Monglia” should be corrected to “Inner Mongolia.” The authors should also check the entire manuscript for consistent formatting of PM₁₀, m·s⁻¹, g·m⁻², m³·m⁻³, and all subscripts and superscripts.
Citation: https://doi.org/10.5194/egusphere-2026-3940-CC1
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- 1
The manuscript addresses an interesting and timely question: whether recent changes in Mongolian cyclone activity can explain spatially divergent dust variability across northwest China. However, I do not think the central conclusion is currently supported by the analysis. My main concern is the Taklimakan–Alxa comparison. The manuscript uses these two regions to diagnose contrasting responses to Mongolian cyclone forcing, yet the Taklimakan is described as topographically sheltered and only weakly influenced by Mongolian cyclones. However, synoptic-scale cyclone forcing may interact with the basin topography and generate mesoscale and local wind systems in the Tarim Basin. While the Mongolia–Gobi source region, which is much more directly linked to Mongolian cyclone activity, is not included. A second concern is the attribution of cyclone change. The manuscript largely infers cyclone intensification and southward displacement from relative vorticity, and then interprets concurrent changes in wind, dust and land-surface variables as a causal pathway. However, there is no objective cyclone tracking or cyclone-conditioned dust analysis. A third concern is the attribution framework. The manuscript interprets concurrent changes in Mongolian cyclones, surface wind, dust, soil moisture and vegetation as evidence of a causal pathway, but the analysis mainly demonstrates statistical associations and synchronized trends. It does not directly quantify how cyclone activity modifies these environmental variables, nor does it test cyclone-conditioned dust responses. Addressing these issues would require substantial re-framing and additional analysis beyond a normal major revision. I therefore recommend rejection.
Major comments
1. The Taklimakan–Alxa comparison does not isolate a Mongolian-cyclone effect.
Relevant text: pp. 2–3, lines 50–80
The manuscript itself argues that the Taklimakan is topographically sheltered and less directly affected by Mongolian cyclones, whereas Alxa is more exposed to northwesterly synoptic flow. Observing opposite dust trends in two regions governed by fundamentally different circulation regimes does not by itself demonstrate a spatially divergent response to Mongolian cyclone forcing. The Taklimakan also contains strong mesoscale (Aoki et al., 2005), thermally driven winds (e.g., low-level jets and haboobs, Chen et al., 2026) and topographically mediated winds, and the northern/eastern basin margins should not be represented by a single prevailing northeasterly regime. Also, the monitoring stations are concentrated along the northern rim of the basin rather than the northeastern edge. Importantly, the Mongolia–Gobi source region, which is more directly linked to Mongolian cyclone activity, is not included in the comparison. The study therefore needs a stronger justification for the regional framework and should distinguish direct cyclone influence from topographically mediated and local circulation effects.
2. Mongolian cyclone activity is not objectively defined or tracked.
Relevant text: p. 1, lines 15–25; pp. 6–7, lines 165–200; p. 12, lines 385–410.
The manuscript infers cyclone intensification and a southward shift mainly from sea-level-pressure and relative-vorticity anomalies. A positive relative-vorticity anomaly is not itself equivalent to an objectively identified Mongolian cyclone, and the paper does not clearly explain how cyclone centres, tracks, frequency and intensity are detected. This is especially important because published cyclone-tracking studies may report different spatial tendencies.
3. Coincident post-2019 changes are treated as causal attribution.
Relevant text: pp. 6–8, lines 165–225; p. 12, lines 390–415.
A central argument is that cyclone intensity/latitude, near-surface wind and dust all changed around 2019–2021. Synchronised changes are not sufficient to establish that cyclone changes caused the dust reversal, particularly over such a short post-break period. Also some statistics are needed to clarify the reverse.
4. ERA5-based long-term surface-wind trends require independent validation.
Relevant text: pp. 3–5, lines 100–155
The main mechanism depends on relatively small long-term changes in near-surface wind derived from ERA5. Reanalysis is useful for circulation diagnostics, but surface-wind trends can be sensitive to models. The claimed wind recovery should therefore be independently evaluated using meteorological-station observations.
5. Pooled station-year correlations may mix spatial and temporal covariance.
Relevant text: p. 5, lines 125–155; pp. 9–10, lines 280–330.
The manuscript pools 26 stations over 10 years (n = 260 station-year pairs) for correlation and segmented-regression analyses. This can confound spatial differences among stations with interannual variability within each station. A positive relationship may therefore partly reflect that dustier locations are also windier, rather than that year-to-year wind anomalies drive year-to-year dust anomalies.
6. Dust metrics are not equivalent and their disagreement needs more careful treatment.
Relevant text: pp. 3–4, lines 90–120; pp. 7–8, lines 205–245.
The manuscript combines PM10, PM10-defined dust-storm days, MERRA-2 DUCMASS and visibility-based dust-storm records. These metrics represent different aspects of aerosol loading, emission and transport and can respond differently to observing practice and background pollution. Over the Taklimakan, the metrics even show contrasting behaviour. Interpreting this disagreement specifically as 'more frequent but weaker dust events' is plausible but not uniquely demonstrated.
7. The future PM10 projection is insufficiently documented and over-interpreted.
Relevant text: p. 4, lines 120–125; p. 12, lines 390–420.
The manuscript projects very large PM10 increases through 2100 using three CMIP6 models, but the workflow linking CMIP6 climate variables to PM10 is not described in sufficient detail. It is unclear how model bias, spatial-scale mismatch, future NDVI/HAI, PGI, soil moisture and cyclone activity are treated or validated. In particular, the claim that future PM10 is primarily controlled by climate-driven strengthening of Mongolian cyclone activity requires explicit diagnosis of future cyclone behaviour. Without this, the future attribution and the very large projected increases are not sufficiently supported.
8. Spatial heterogeneity within the Taklimakan is under-resolved.
Relevant text: pp. 7–8, lines 210–225.
Again, treating the entire Tarim Basin as one homogeneous source region may obscure substantial differences among the northern, eastern and southern basin margins, where dust activation and wind regimes differ. And I did not see any maps reporting this spatial distribution.
9. Causal language throughout the manuscript is stronger than the evidence supports.
Relevant text: p. 1, lines 15–25; p. 13, lines 420–425.
The manuscript frequently moves from association or predictive importance to causal statements, including claims that Mongolian cyclone intensification ‘reshapes’ dust activity, that wind is a direct reflection of cyclone forcing, and that large-scale circulation outweighs land-surface controls. The analyses presented are primarily observational and statistical. Unless stronger causal tests are added, the Abstract, Results, Discussion and Conclusions should consistently distinguish association, prediction and physical causation.
Other comments:
Page 1, Lines 12–14: Please specify what is meant by “recent years.” Dust activity has generally been reported to decrease over a longer period, so the recent increase may partly reflect interannual or decadal variability.
Page 1, Lines 15–16: The previous sentence mentions both land-surface changes and circulation changes, but here the knowledge gap refers only to circulation changes. Please clarify the role of land-surface changes in the identified gap.
Page 1, Lines 16–18: The Taklimakan Desert is relatively weakly affected by Mongolian cyclones, as the authors also acknowledge later in the manuscript. Therefore, the rationale for investigating Mongolian cyclone impacts on the Taklimakan should be clarified.
Page 1, Lines 18–20: Please double-check the reported southward shift after 2019. Mu and Fiedler (2025) appear to report a different, or northward, tendency for Mongolian cyclone activity.
Page 2, Lines 38–43: I do not fully understand why the increasing contribution of Mongolia as a dust source is introduced here, as this study mainly investigates dust activity within China. Please clarify its relevance to the study objective.
Page 2, Lines 45–48: The preceding sentences describe different mechanisms, but it is unclear how they lead directly to the stated central question about Mongolian cyclone control. The logical connection could be strengthened.
Page 2, Lines 49–50: I am not sure that land-surface properties and Mongolian cyclone activity should be framed together in this way.
Page 2, Lines 50–52: The manuscript later examines the effects of wind, precipitation, soil moisture and vegetation on dust activity, rather than explicitly quantifying how Mongolian cyclones modulate each of these variables. Please revise this statement accordingly.
Page 2, Lines 55–58: I do not think an increase in dust storms and a greening trend necessarily constitute a direct contradiction, as they describe different processes. In addition, much of the post-2021 dust resurgence in northern China might originate from the broad Gobi region rather than the Taklimakan. Please clarify how this motivates the focus on Mongolian cyclones.
Page 3, Lines 65–69: The first part of this paragraph discusses environmental controls on dust, whereas the final sentence shifts to the lack of long-term studies versus individual dust-storm events. I do not see a clear logical connection between these points; they may need to be separated or better linked.
Page 3, Line 70: “Building on this foundation” is unclear. Does “this foundation” refer to the divergent dust behaviour between the Taklimakan and Alxa regions? Please specify.
Page 3, Lines 70–72: Why is Mu Us Sandy Land not included here, given that it was introduced earlier as one of the study regions? Also, please clarify why the Mongolian Plateau itself is not considered.
Page 3, Lines 71–73: The second hypothesis is presented as a hypothesis of this study but is immediately supported by a citation to another study, which is confusing. I think the intended comparison may instead be between the Tarim Basin interior and regions outside the basin; please clarify.
Page 3, Lines 73–74: It is not clear how the authors establish that there is “significant controversy” regarding the primary driving mechanisms. There is certainly debate regarding dust trends, but the basic physical controls on dust emission might be relatively well established. Please clarify what specific controversy is meant.
Page 3, Line 84: Please check the letter/article formatting here.
Page 3, Lines 85–89: Four dust-storm centres are mentioned, but the study subsequently focuses on only two major source regions. Please clarify the relationship between these four centres and the regions actually analysed.
Page 6, Lines 165–167: The “recent rebound of dust storm activity” is introduced before the corresponding dust records are presented. It may be clearer to present the observational evidence for the dust rebound first and then investigate the associated circulation changes.
Page 6, Lines 168–171: I am not convinced that the change in relative vorticity alone is sufficient to identify an intensified and southward-shifted Mongolian cyclone. Positive relative vorticity indicates cyclonic circulation but does not necessarily identify a cyclone centre. In addition, Mu and Fiedler (2025), using an explicit cyclone-tracking algorithm, report a different trend. A more robust cyclone identification/tracking method or additional circulation diagnostics would be helpful.
Page 7, Line 175: Could the authors provide the corresponding figure or analysis supporting this value?
Page 7, Lines 176–178: The text states that the regional wind-speed differences are shown in Fig. S1A, but I cannot clearly identify these details in that figure. Please check the figure reference or make the differences more explicit.
Page 7, Lines 190–194: Please double-check whether Mu and Fiedler (2025) actually demonstrate that topographic shielding weakens Mongolian cyclone influence on the Taklimakan in the way stated here. My understanding is that they identify this as an issue requiring further investigation rather than establishing it directly.
Page 7, Lines 195–202: This discussion introduces Arctic forcing and dust-radiative feedbacks, but no analysis or figure in this study directly evaluates these mechanisms. At present, these statements rely mainly on previous studies and appear somewhat detached from the analyses presented here.
Page 8, Lines 213–216: The statement that the entire Tarim Basin is dominated by northeasterly winds may be too general. The northern rim of the basin is also an active dust-source region associated with different wind regimes (e.g., Chen et al., 2026, ACP). Regional differences within the basin should be considered.
Page 8, Lines 216–219: The text gives percentage changes between the two periods, but were these changes tested for statistical significance? Earlier sections state that the study aims to “quantify” these changes, so significance or uncertainty should also be reported.
Page 8, Lines 220–223: It would be useful to show the spatial pattern of the DUCMASS trends rather than only basin-mean values. I suspect that the eastern and northern parts of the Tarim Basin may exhibit different trends, which could be obscured by averaging over the whole basin. .
Page 9, Lines 247–250: Why is March used for the long-term wind analysis? Dust activity and circulation can differ substantially between spring months (Wang et al., 2026), so the choice of March requires justification, or the authors could examine the full spring season and individual spring months separately.