Karimi et al. (2025) Evolution of mass loss at Alamkouh Glacier in Iran using multi-temporal high-resolution DEMs between 2010 and 2023

Identification

• Journal: Environmental Monitoring and Assessment
• Year: 2025
• Date: 2025-09-10
• Authors: Neamat Karimi, Sara Sheshangosht
• DOI: 10.1007/s10661-025-14442-3

Research Groups

• Department of Water Resources Study and Research, Water Research Institute, Tehran, Iran

Short Summary

This study quantifies the surface elevation changes and mass loss of Alamkouh Glacier, Iran, between 2010 and 2023 using multi-temporal high-resolution DEMs, revealing an average mass balance of −0.20 ± 0.04 meters water equivalent per year and highlighting the significant impact of supraglacial features on melt rates.

Objective

• To perform a multi-temporal quantification of surface elevation changes and mass balance measurements of the Alamkouh Glacier from 2010 to 2023, employing a combination of three high-resolution Unmanned Aerial Vehicle (UAV) surveys and one LiDAR survey.
• To assess the impact of various supraglacial features, such as ice cliffs, supraglacial ponds, and debris cover, on the glacier’s mass loss rate.
• To compare the results obtained from the Alamkouh Glacier with those from other glaciers, thereby contextualizing its behavior within broader glaciological trends.

Study Configuration

• Spatial Scale: Alamkouh Glacier, Takht-e Soleyman Massif, Alburz Mountains, northern Iran. The glacier covers an area of approximately 3.8 square kilometers, with elevations ranging from 3750 meters to 4393 meters above sea level.
• Temporal Scale: The study period spans from 2010 to 2023, analyzed across three sub-periods: 2010–2018, 2018–2020, and 2020–2023.

Methodology and Data

• Models used:
  • Geodetic methods for quantifying glacier mass balance and surface elevation changes.
  • Quadratic surface fitting for co-registration and systematic bias correction of Digital Elevation Models (DEMs).
  • Spatially variable density approach (adapted from Kääb et al., 2012) for converting volume change to mass balance, assigning densities of 900 kilograms per cubic meter (kg/m³) for debris-covered ice/exposed ice cliffs, 600 kg/m³ for debris-free/firn zones, and 1000 kg/m³ for supraglacial ponds.
  • Uncertainty analysis for mass balance measurements based on approaches by Cao et al. (2020) and Zhang et al. (2018), utilizing Normalized Median Absolute Deviation (NMAD).
• Data sources:
  • LiDAR data (2010): Riegl LMS-Q560 sensor, generating a DEM with 0.20 meters spatial resolution and an orthophoto with 0.10 meters spatial resolution.
  • UAV data (2018, 2020, 2023):
    • 2018: DJI Phantom 4 PRO V2.0, producing a DEM and orthophoto with 0.10 meters spatial resolution.
    • 2020: DJI Phantom 4 PRO V2.0, producing a DEM with 0.15 meters spatial resolution.
    • 2023: Sahab-E2 UAV (VTOL fixed-wing with 42-megapixel camera and DGPS), producing a DEM with 0.10 meters spatial resolution.
  • Ground Control Points (GCPs) and Ground Validation Points (GVPs): Acquired using differential GPS (DGPS) for DEM generation, co-registration, and accuracy assessment.
  • Manual digitization: High-resolution aerial images were manually digitized to classify glacier surface features (supraglacial ponds, ice cliffs, debris-free, and debris-covered areas).

Main Results

• The Alamkouh Glacier experienced an average mass balance of approximately −0.20 ± 0.04 meters water equivalent per year (m w.e.a⁻¹) from 2010 to 2023.
• Mass loss accelerated over the study period: −0.18 ± 0.03 m w.e.a⁻¹ (2010–2018), −0.24 ± 0.04 m w.e.a⁻¹ (2018–2020), and −0.25 ± 0.04 m w.e.a⁻¹ (2020–2023).
• The average thinning rate of the glacier was 0.24 ± 0.05 m/a from 2010 to 2023, with a slight acceleration in the latter part of the study.
• Supraglacial features significantly impact melt rates:
  • Supraglacial ponds showed the highest mean ice thinning rate of −1.09 ± 0.35 m/a (5.5 times greater than debris-covered areas).
  • Ice cliffs exhibited a mean thinning rate of −0.73 ± 0.25 m/a (3.6 times greater than debris-covered areas).
  • Debris-free areas had a mean thinning rate of −0.64 ± 0.20 m/a (3.2 times greater than debris-covered areas).
  • Debris-covered areas showed the lowest mean thinning rate of −0.20 ± 0.24 m/a, attributed to the insulating effect of debris.
• The area of ice cliffs increased consistently from 34,500 m² in 2010 to 43,800 m² in 2023, correlating with periods of maximum thinning. Supraglacial pond area showed no clear temporal trend.
• The Alamkouh Glacier exhibits a relatively moderate rate of mass loss compared to the global average (−0.48 ± 0.20 m w.e.a⁻¹) and many other glaciers worldwide.

Contributions

• Provides the first multi-temporal, high-resolution quantification of surface elevation changes and mass balance for the Alamkouh Glacier from 2010 to 2023, offering a detailed understanding of its current state.
• Offers crucial insights into the local processes and the significant role of supraglacial features (ponds, ice cliffs, debris cover) in controlling glacier melt dynamics in debris-covered, small, low-altitude, and arid/semi-arid region glaciers.
• Demonstrates the superior capability of UAV-derived datasets in capturing fine-scale surface heterogeneity and spatial variability in glacier melt processes, which is challenging for satellite imagery or traditional in-situ measurements.
• Corroborates global findings on the importance of supraglacial ponds and ice cliffs as hotspots of enhanced ablation on debris-covered glaciers.
• Underscores the critical need for continuous monitoring and detailed modeling using high-resolution UAV data to understand and predict future glacier trends, informing effective management and conservation strategies.

Funding

• Water Research Institute (WRI) of Iran provided essential resources and facilities.

Citation

@article{Karimi2025Evolution,
  author = {Karimi, Neamat and Sheshangosht, Sara},
  title = {Evolution of mass loss at Alamkouh Glacier in Iran using multi-temporal high-resolution DEMs between 2010 and 2023},
  journal = {Environmental Monitoring and Assessment},
  year = {2025},
  doi = {10.1007/s10661-025-14442-3},
  url = {https://doi.org/10.1007/s10661-025-14442-3}
}