the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 07 Mar 2025
Analysis of Snow Cover Changes Using MODIS Snow Products and Meteorological Data in the Hunza Region, Karakoram, Pakistan
Abstract. The Upper Indus Basin (UIB) is characterized by contrasting meteorological behaviors; therefore, it has become pertinent to understand the meteorological trends at the sub-basin level. Many studies have investigated the snow-covered area along with meteorological trends at the basin level. Still, none have reported the spatial variability of trends and their magnitude at a sub-basin level. This study is conducted to monitor the seasonal trends in the snow-covered area and climatic factors (temperature and precipitation) in the Hunza region of the Upper Indus Basin (UIB). Summer and winter seasons were selected because temperature and precipitation during these two seasons are the key factors for snow cover variation in the region. Mann-Kendall and Spearman methods were used to study the seasonal trends and their magnitude using MODIS snow cover information (2000–2020) and meteorological data. The results showed that during the summer season, SCA and precipitation showed a non-significant (p=0.05) decreasing trend with a value of -0.0095 km²/month and -0.191 mm/month, respectively, while the temperature showed a non-significant increasing trend with a value of 0.315 °C/month. While, during the winter season, SCA and temperature showed a non-significant increasing trend with a value of 0.114 km²/month and 0.176 °C/month, respectively, and precipitation showed a significant increasing trend with a value of 0.436 mm/month. In general, the snow-covered areas of the Hunza region have an increasing trend during the winter season, while the summer season has a decreasing trend of snow-covered areas. Based on the results of this study it can be concluded that since the Hunza sub-basin of the UIB is influenced by a different climatological system (westerly system) as compared to other sub-basins of the UIB (monsoon systems), the results of those studies that treat the UIB as one unit in meteorological modeling should be used with caution. Furthermore, it is suggested that similar studies at the sub-basin level of the UIB will help in a better understanding of the Karakoram anomaly.
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RC1: 'Comment on egusphere-2024-3991', Anonymous Referee #1, 04 Apr 2025
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This manuscript, entitled “Analysis of Snow Cover Changes Using MODIS Snow Products and Meteorological Data in the Hunza Region, Karakoram, Pakistan”, presents an analysis of snow cover area (SCA) seasonal variability and trend in the Karakoram region (2000-2020 period). To pursue this aim, MODIS data, as well as in situ meteorological observations (temperature and precipitation), have been adopted. The manuscript deals with an interesting topic, that can be surely of interest for the audience of The Cryosphere. However, at current stage, I consider this work not suitable for publication, due to several deficiencies related to the method description, the quality of the presentation and the discussion of the results.
Main comments
- The first critical point regards the English, which is very poor. Several sentences have written without a verb (e.g. pag. 11, Lines 172-173; pag. 16, Line 228). In addition, many sentences and concepts are redundant. There are also several typos, sometimes the acronyms are used before they have been explicitly stated and the references are cited in the main text with a non-uniform style.
- From a methodological perspective, there are several “dark points” that should be clarified:
- Line 99: very poor method to reconstruct missing data in a time series.
- Line 94: it is necessary to provide additional details about the method used to classify the Landsat images.
- Line 136: why 8-day interval images? Can you justify this choice?
- Figure 4 does not provide clear information about the altitudinal zones extracted from GDEM. It is not clear which is the altitudinal range of the elevation zones B and C.
- The scientific quality of the analysis is poor and is limited to a simple and basic discussion of the trend of SCA and meteorological variables, without an in-depth investigation about other potential drivers of SCA variability (e.g. teleconnection patterns). In this sense, additional efforts should be carried out.
- Finally, I suggest to strongly improve the quality and style of the figures.
Minor comments
- Line 9: The acronym SCA has been not explicitly stated.
- Line 36: The acronym HKH has been not explicitly stated.
- Line 30: “according to the Intergovernmental Panel on Climate Change (IPCC) report titled “State of the Global Climate 2020 WMO-No. 1264”, between 1880-2020 where the average land and ocean temperature has increased globally by 1.2°C.” This sentence should be carefully revised.
- Line 53: “Immerzeel et al. (2009) the same pattern was observed between 2000 and 2008.” Please carefully check the English grammar.
- Line 67: The acronym UIB has been just explicitly stated at this point of the manuscript.
- Line 99: What is the percentage of missing data?
- Line 107: ”Winter (March) and Summer (August)”. Season should be from a determined month to another month.
- Line 110: the acronym MK is not explicitly stated;
- Line 121: “is defined using the using the”. Please revise this sentence.
- Line 125:” data at a resolution of 30-meter resolutions”. Please carefully revise this sentence.
- Line 125: To address these voids in the STRM DEM were filled using the fill function in ArcMap”. This sentence is not clear.
- Line 126: “data was”. Please check the Englis grammar.
- Line 129: Figure 2.2?
- Line 133: The equations should be carefully revised. A detailed description of the parameters embedded in them is missing.
- Tables 2 e 3 are not mentioned in the main text.
- Line 153: What represent the red and blue lines in this figure? An average between the two stations? Please clarify. In addition, please uniform the style of this figure to that of Figure 6.
- Lines 172-177: this concept is not clear and the sentences seem to be not adequately connected among each other.
- Line 186: “The trend analysis of SCA during the summer season is shown in Figure 8 SCA analysis during the summer season represents a non-significant declining trend for the period of 2000 to 2020”. Please carefully revise this sentence.
- Line 198: “The trend analysis of SCA during the winter season is shown in Figure 10 SCA analysis during the winter season represents a minute, non-significant increasing trend for the period of 2000 to 2020”. Please carefully revise this sentence.
- Line 201: The SCD trend in winter is not significant, as the authors state in the Abstract. Please carefully check.
- Lines 207-210: “32.5% of the Hunza Basin region is located above 5,000 meters above sea level, and the seasonal variation in snow cover ranges from 38 to 43%. At this altitude, temperatures remain below freezing throughout the year and precipitation tends to increase. This may be the reason for the increase in snow cover in the Hunza basin and the advance of some glaciers.” This concept has been introduced in the previous Line.
- Line 210:” (Hewitt, 2005; Archer and Fowler, 2004) also concluded”. Please revise this sentence.
- Line 218: “Figures 11 represent”. Please check the English grammar.
- Lines 233-241: Please carefully revise such sentences.
Best regards.
Citation: https://doi.org/10.5194/egusphere-2024-3991-RC1
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