Zhang et al. (2026) Satellite-Derived Summer Albedo Variations on the Greenland Ice Sheet from 1979 to 2024 Linked with Climatic Indices

Identification

• Journal: Remote Sensing
• Year: 2026
• Date: 2026-01-16
• Authors: Yulun Zhang, Shang Geng, Yetang Wang
• DOI: 10.3390/rs18020295

Research Groups

• College of Geography and Environment, Shandong Normal University, Jinan, China

Short Summary

This study evaluates the CLARA-A3-SAL satellite albedo product over the Greenland Ice Sheet (GrIS) and analyzes summer albedo trends from 1979 to 2024, revealing a significant overall decline driven by meltwater processes and modulated by large-scale atmospheric circulation patterns.

Objective

• To evaluate the performance of the CLARA-A3-SAL satellite albedo product over the Greenland Ice Sheet (GrIS) using in situ observations.
• To investigate the spatiotemporal trends of summer albedo across the GrIS from 1979 to 2024.
• To examine the relationships between summer albedo variations and regional surface conditions (temperature, snowfall, melt) and large-scale atmospheric circulation indices (NAO, GBI, AMO, PDO).

Study Configuration

• Spatial Scale: Greenland Ice Sheet (GrIS), divided into dry snow and non-dry snow (percolation and bare ice) zones. Data provided on a 0.25° × 0.25° global grid and 25 km × 25 km polar subsets (EASE-2 projection).
• Temporal Scale: Summer months (June–July–August, JJA) from 1979 to 2024.

Methodology and Data

• Models used:
  • Modèle Atmosphérique Régional (MAR) version 3.12.0 for snowmelt data.
• Data sources:
  • Satellite: CLARA-A3-SAL (black-sky albedo) product derived from Advanced Very High Resolution Radiometer (AVHRR) sensors.
  • Observation (in situ): Monthly surface albedo from 32 automatic weather stations of the Programme for Monitoring of the GrIS (PROMICE) and Greenland Climate Network (GC-Net).
  • Reanalysis: ERA5 (ECMWF) for monthly 2 m air temperature and snowfall data.
  • Climate Indices: Greenland Blocking Index (GBI), North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), and Pacific Decadal Oscillation (PDO) from NOAA.

Main Results

• The CLARA-A3-SAL product shows improved performance over GrIS, with mean biases less than 0.05 and RMSE values ranging from 0.01 to 0.07 in the interior dry snow zone. While larger errors (MB and RMSE > 0.2) exist in coastal ablation zones due to surface heterogeneity, the product effectively captures interannual variability (correlation coefficients generally > 0.6) and long-term trends.
• The average summer surface albedo over the entire GrIS decreased significantly at a rate of −0.24% per decade from 1979 to 2024.
• Spatially, the dry snow zone exhibited relative stability with a negligible albedo trend (−0.01% per decade), showing weak correlations with most climate variables except NAO and GBI.
• The non-dry snow (marginal) zone experienced substantial darkening, with an albedo decline of −0.66% per decade. This darkening is strongly correlated with temperature (r = −0.77, p < 0.05), snowfall (r = 0.60, p < 0.05), and meltwater (r = −0.90, p < 0.01), indicating meltwater-driven grain growth and bare ice exposure as primary drivers.
• A segmented linear regression identified an abrupt shift around 1986, after which coastal darkening accelerated, exceeding −4% per decade in some regions.
• Large-scale atmospheric circulation patterns significantly modulate albedo changes:
  • The Greenland Blocking Index (GBI) shows the strongest negative correlation with albedo (r = −0.63, p < 0.05 for overall GrIS; r = −0.72 in non-dry snow regions), highlighting the role of persistent blocking in amplifying warming and darkening.
  • The North Atlantic Oscillation (NAO) exhibits a significant positive correlation with albedo (r = 0.43).
  • The Atlantic Multidecadal Oscillation (AMO) is predominantly negatively correlated with albedo (r = 0.6 along the GrIS coast), with its warm phase (AMO+) generally linked to reduced albedo.
  • The Pacific Decadal Oscillation (PDO) shows an overall positive correlation with albedo (r = 0.53), with its positive phase tending to enhance albedo.

Contributions

• Provides the first systematic evaluation of the newest CLARA-A3-SAL satellite albedo product over the Greenland Ice Sheet, confirming its reliability for long-term climate studies.
• Extends the analysis of GrIS summer albedo trends to the longest continuous period available (1979–2024), offering a robust assessment of multi-decadal changes.
• Quantifies the distinct roles of regional surface conditions (meltwater, temperature, snowfall) and large-scale atmospheric circulation patterns (NAO, GBI, AMO, PDO) in driving the observed spatiotemporal variability and decline of GrIS albedo.
• Highlights the critical need for accurately representing albedo–melt–circulation interactions in future climate and ice-sheet models due to the pronounced sensitivity of albedo to these factors.

Funding

• Shandong Province Science Foundation for Youths (Grant Number: ZR2024QD254)
• National Key Research and Development Program of China (Grant Number: 2020YFA0608202)
• Taishan Scholars Program of Shandong Province (Grant Number: tsqn202312158)
• National Natural Science Foundation of China (Grant Number: 41971081)

Citation

@article{Zhang2026SatelliteDerived,
  author = {Zhang, Yulun and Geng, Shang and Wang, Yetang},
  title = {Satellite-Derived Summer Albedo Variations on the Greenland Ice Sheet from 1979 to 2024 Linked with Climatic Indices},
  journal = {Remote Sensing},
  year = {2026},
  doi = {10.3390/rs18020295},
  url = {https://doi.org/10.3390/rs18020295}
}