the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 19 Sep 2024
PDO-driven interdecadal variability of snowfall over the Karakoram and Western Himalaya
Abstract. Our study reveals that the negative phase of the Pacific Decadal Oscillation (PDO−) leads to increased winter (DJF) snowfall in the Karakoram and Western Himalayas (KH) from 1940 to 2022. Interdecadal variations in DJF snowfall during the PDO− are attributed to deep convection and adiabatic cooling near the tropopause in both the northwest Pacific and KH region. Additionally, a wave-like pattern characterized by a trough (anomalous cyclone) north of KH and a ridge (anomalous Tibetan Plateau anticyclone) east of KH in the upper atmosphere, along the northward shift of the DJF Subtropical Jet (STJ) was observed. A strong positive correlation between DJF STJ strength and DJF snowfall in KH as well as a significant negative correlation between DJF STJ strength and DJF PDO, suggests a wave response over KH to the direct forcing over the northwest Pacific Ocean. The intensified STJ across KH results in higher frequency of Western disturbances, leading to anomalous moisture convergence and increased DJF precipitation in the region during the PDO−. These findings hold significant implications for the decadal predictability of winter snowfall in KH by the various phases of PDO.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(4369 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(4369 KB) - Metadata XML
- BibTeX
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-2845', Anonymous Referee #1, 21 Oct 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2845/egusphere-2024-2845-RC1-supplement.pdf
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AC1: 'Reply on RC1', Priya Bharati, 18 Nov 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2845/egusphere-2024-2845-AC1-supplement.pdf
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AC1: 'Reply on RC1', Priya Bharati, 18 Nov 2024
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RC2: 'Comment on egusphere-2024-2845', Anonymous Referee #2, 03 Nov 2024
Review of the manuscript egusphere-2024-2845 entitled “PDO-driven interdecadal variability of snowfall over the Karakoram and Western Himalaya” by Bharati et al.
Snowfall not only affects the mass balance of glaciers but is also an important source of water resources in arid and semi-arid areas. The Karakoram and Western Himalaya regions are home to numerous high mountain glaciers, serving as the sources for rivers such as the Indus, Tarim, and Amu Darya. The unique characteristics of the Karakoram anomaly have drawn sustained attention from the academic community. This article explores the relationship between the Pacific Decadal Oscillation (PDO) and winter snowfall in the Karakoram-Western Himalaya region, analyzing the mechanisms involved. The paper is well-written and presents a clear line of thought. I recommend that the paper be published in Weather and Climate Dynamics following revisions.
#Major
Lines 98-104: While these interdecadal factors (PDO, IPO, and AMO) significantly influence global climate, could you explain why this article focuses solely on the impact of the PDO?
Lines 107-109: A published study examines the impact of the PDO on non-monsoon season precipitation in the northwestern Himalayas, highlighting its role in regulating westerly disturbances (Aggarwal et al. 2024, CD). Please introduce it here and emphasize the differences with this work.
From Figure 1a, it can be observed that the precipitation values from the reanalysis data are significantly higher than those from the assimilated grid precipitation data. Additionally, the reanalysis data exhibits more pronounced interdecadal variability. What factors contribute to this discrepancy? This article is primarily based on ERA5 data. what impact does this have on the results? Please discuss.
From your analysis, it is clear that there is a significant correlation between PDO, WD, and snowfall. However, the article does not clearly explain how the PDO influences the westerly disturbances in the Karakoram-Western Himalayan region through teleconnection processes. Additionally, is it possible to validate the process by which the PDO affects winter snowfall in the Karakoram-Western Himalayan region through modeling experiments?
#Minor
Line 76: Add a space before WD.
Please include some recent references in the introduction.
Line 126: The following analysis uses data up to 2023 (Table 1), but here mentions data only up to 2022. Please check.
Line 162: Could you clarify the temporal resolution of the data used for the calculations in this section?
Lines 206-217: When calculating the correlation of snowfall in the Karakoram -Western Himalaya region with other indices, was the part of the region with significantly positive correlation coefficients (Fig 2a) excluded? If not, I recommend excluding it before recalculating, as this will likely yield more reliable results.
Line 453: I did not see any information regarding significance testing, please check. If there isn't any, please add it.
Figure 6, please use the same aspect ratio (width to height).
Related references:
Aggarwal D, Chakraborty R, Attada R. Investigating bi-decadal precipitation changes over the Northwest Himalayas during the pre-monsoon: role of Pacific decadal oscillations. Climate Dynamics. 2024 Feb;62(2):1203-18.
Dimri AP, Pooja, Jeelani G, Mohanty UC. Western disturbances vs Non-western disturbances days winter precipitation. Climate Dynamics. 2023 Nov;61(9):4825-47.
Citation: https://doi.org/10.5194/egusphere-2024-2845-RC2 -
AC2: 'Reply on RC2', Priya Bharati, 18 Nov 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2845/egusphere-2024-2845-AC2-supplement.pdf
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AC2: 'Reply on RC2', Priya Bharati, 18 Nov 2024
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2024-2845', Anonymous Referee #1, 21 Oct 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2845/egusphere-2024-2845-RC1-supplement.pdf
-
AC1: 'Reply on RC1', Priya Bharati, 18 Nov 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2845/egusphere-2024-2845-AC1-supplement.pdf
-
AC1: 'Reply on RC1', Priya Bharati, 18 Nov 2024
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RC2: 'Comment on egusphere-2024-2845', Anonymous Referee #2, 03 Nov 2024
Review of the manuscript egusphere-2024-2845 entitled “PDO-driven interdecadal variability of snowfall over the Karakoram and Western Himalaya” by Bharati et al.
Snowfall not only affects the mass balance of glaciers but is also an important source of water resources in arid and semi-arid areas. The Karakoram and Western Himalaya regions are home to numerous high mountain glaciers, serving as the sources for rivers such as the Indus, Tarim, and Amu Darya. The unique characteristics of the Karakoram anomaly have drawn sustained attention from the academic community. This article explores the relationship between the Pacific Decadal Oscillation (PDO) and winter snowfall in the Karakoram-Western Himalaya region, analyzing the mechanisms involved. The paper is well-written and presents a clear line of thought. I recommend that the paper be published in Weather and Climate Dynamics following revisions.
#Major
Lines 98-104: While these interdecadal factors (PDO, IPO, and AMO) significantly influence global climate, could you explain why this article focuses solely on the impact of the PDO?
Lines 107-109: A published study examines the impact of the PDO on non-monsoon season precipitation in the northwestern Himalayas, highlighting its role in regulating westerly disturbances (Aggarwal et al. 2024, CD). Please introduce it here and emphasize the differences with this work.
From Figure 1a, it can be observed that the precipitation values from the reanalysis data are significantly higher than those from the assimilated grid precipitation data. Additionally, the reanalysis data exhibits more pronounced interdecadal variability. What factors contribute to this discrepancy? This article is primarily based on ERA5 data. what impact does this have on the results? Please discuss.
From your analysis, it is clear that there is a significant correlation between PDO, WD, and snowfall. However, the article does not clearly explain how the PDO influences the westerly disturbances in the Karakoram-Western Himalayan region through teleconnection processes. Additionally, is it possible to validate the process by which the PDO affects winter snowfall in the Karakoram-Western Himalayan region through modeling experiments?
#Minor
Line 76: Add a space before WD.
Please include some recent references in the introduction.
Line 126: The following analysis uses data up to 2023 (Table 1), but here mentions data only up to 2022. Please check.
Line 162: Could you clarify the temporal resolution of the data used for the calculations in this section?
Lines 206-217: When calculating the correlation of snowfall in the Karakoram -Western Himalaya region with other indices, was the part of the region with significantly positive correlation coefficients (Fig 2a) excluded? If not, I recommend excluding it before recalculating, as this will likely yield more reliable results.
Line 453: I did not see any information regarding significance testing, please check. If there isn't any, please add it.
Figure 6, please use the same aspect ratio (width to height).
Related references:
Aggarwal D, Chakraborty R, Attada R. Investigating bi-decadal precipitation changes over the Northwest Himalayas during the pre-monsoon: role of Pacific decadal oscillations. Climate Dynamics. 2024 Feb;62(2):1203-18.
Dimri AP, Pooja, Jeelani G, Mohanty UC. Western disturbances vs Non-western disturbances days winter precipitation. Climate Dynamics. 2023 Nov;61(9):4825-47.
Citation: https://doi.org/10.5194/egusphere-2024-2845-RC2 -
AC2: 'Reply on RC2', Priya Bharati, 18 Nov 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2845/egusphere-2024-2845-AC2-supplement.pdf
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AC2: 'Reply on RC2', Priya Bharati, 18 Nov 2024
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Priya Bharati
Kieran M. R. Hunt
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(4369 KB) - Metadata XML
Snowfall in the Karakoram and Western Himalayas (KH) correlates negatively with the Pacific Decadal Oscillation (PDO) during the winter (DJF). A wave-like pattern in the upper atmosphere, accompanied with a northward moving subtropical jet over KH, is associated with warm SST in the northwest Pacific Ocean. More frequent western disturbances (WDs) migrated north of KH region during the negative phase of PDO, resulting in increased moisture transport to the KH.
Snowfall in the Karakoram and Western Himalayas (KH) correlates negatively with the Pacific...