Preprints
https://doi.org/10.5194/egusphere-2024-676
https://doi.org/10.5194/egusphere-2024-676
18 Mar 2024
 | 18 Mar 2024
Status: this preprint is open for discussion.

El Niño Enhances Snowline Rise and Ice Loss on the World's Largest Tropical Ice Cap

Kara A. Lamantia, Laura J. Larocca, Lonnie G. Thompson, and Bryan G. Mark

Abstract. Tropical glaciers are essential water resources in the central Andes as vital water resources and crucial climate indicators, currently undergoing rapid retreat. However, understanding their vulnerability to the combined effects of persistent warming, short-term climate phenomena, and interannual fluctuations remains limited. Here we automate mapping of key mass balance parameters on the Quelccaya Ice Cap (QIC), the world’s largest tropical ice cap. Using Landsat's near-infrared (NIR) band, we analyze snow cover area (SCA) and total area (TA) and calculate the Accumulation Area Ratio (AAR) and Equilibrium Line Altitude (ELA) over nearly 40 years (1985–2023). Between 1985 and 2022, the QIC lost ~46 % and ~34 % of its SCA and TA, respectively. We show that the QIC’s loss in SCA and rise in ELA are exacerbated by El Niño events, which are strongly correlated to the preceding wet season’s Ocean Niño Index (ONI). We observe lower levels of correlation to more recent El Niño events as anthropogenic climatic impacts overwhelm the natural forcing and continue to exacerbate loss at the QIC.

Kara A. Lamantia, Laura J. Larocca, Lonnie G. Thompson, and Bryan G. Mark

Status: open (until 29 Apr 2024)

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  • RC1: 'Comment on egusphere-2024-676', Anonymous Referee #1, 09 Apr 2024 reply
Kara A. Lamantia, Laura J. Larocca, Lonnie G. Thompson, and Bryan G. Mark
Kara A. Lamantia, Laura J. Larocca, Lonnie G. Thompson, and Bryan G. Mark

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Short summary
Glaciers that exist within tropical regions are a vital water resource and excellent indicators of changing climate. We use satellite imagery analysis to detect the boundary between snow and ice on the Quelccaya Ice Cap (QIC) in Peru, the world’s largest tropical ice cap. This indicates the QIC’s health and can be analyzed with other variables such as temperature, precipitation, and sea surface temperature anomalies to better understand what factors on what timeline are driving the ice retreat.