Supplementary data for: "Early aerial expedition photos reveal 85 years of glacier growth and stability in East Antarctica"

<i>Mads Dømgaard</i>^<em>1</em><i>, Anders Schomacker</i>^<em>2</em><i>, Elisabeth Isaksson</i>^<em>3</em><i>, Romain Millan</i>^<em>4</em><i>, Flora Huiban</i>^<em>1</em><i>, Amaury Dehecq</i>^<em>4</em><i>, Amanda Fleischer</i>^<em>1</em><i>, Geir Moholdt</i>^<em>3</em><i>, Jonas K. Andersen</i>^<em>1</em><i>, Anders A. Bjørk</i>^<em>1</em>^<em>1</em><i>Department of Geoscience and Natural Resource Management, University of Copenhagen, 1350 Copenhagen K, Denmark</i>^<em>2</em><i>Department of Geosciences, UiT The Arctic University of Norway, Postboks 6050 Langnes, NO-9037 Tromsø, Norway</i>^<em>3</em><i>Norwegian Polar Institute, 9296 Tromsø, Norway</i>^<em>4</em><i>Univ. Grenoble Alpes, IRD, CNRS, INRAE, Grenoble INP, IGE, 38000 Grenoble, France</i><br><b>Abstract:</b><br>During the last few decades, several sectors in Antarctica have transitioned from glacial mass balance equilibrium to mass loss. In order to determine if recent trends exceed the scale of natural variability, long-term observations are vital. Here we explore the earliest, large-scale, aerial image archive of Antarctica to provide a unique record of 21 outlet glaciers along the coastline of East Antarctica since the 1930s. In Lützow-Holm Bay, our results reveal constant ice surface elevations since the 1930s, and indications of a weakening of local land-fast sea-ice conditions. Along the coastline of Kemp and Mac Robertson, and Ingrid Christensen Coast, we observe a long-term moderate thickening of the glaciers since 1937 and 1960 with periodic thinning and decadal variability. In all regions, the long-term changes in ice thickness correspond with the trends in snowfall since 1940. Our results demonstrate that the stability and growth in ice elevations observed in terrestrial basins over the past few decades are part of a trend spanning at least a century, and highlight the importance of understanding long-term changes when interpreting current dynamics.<br><br><b>Data description:</b>This dataset contains produced DEMs, orthophoto mosaics, ice front positions, surface flow velocity, and dH estimates derived from Norwegian and Australian aerial expedition images captured along the east Antarctic coastline (Lützow-Holm Bay (38° East) to Ingrid Christensen Coast (79° East)) between 1937 and 1973. The DEMs and orthophoto mosaics were generated using structure-from-motion (SfM) photogrammetry in Agisoft Metashape v. 1.7.4.This dataset also includes the codes used for the figures in the article.

Mads Dømgaard¹、Anders Schomacker²、Elisabeth Isaksson³、Romain Millan⁴、Flora Huiban¹、Amaury Dehecq⁴、Amanda Fleischer¹、Geir Moholdt³、Jonas K. Andersen¹、Anders A. Bjørk¹
¹ 哥本哈根大学地球科学与自然资源管理系，丹麦哥本哈根K区1350号
² 挪威北极大学（UiT）地球科学系，挪威特罗姆瑟市朗内斯邮政信箱6050，邮编NO-9037
³ 挪威极地研究所，挪威特罗姆瑟市9296号
⁴ 格勒诺布尔阿尔卑斯大学、法国发展研究所（IRD）、法国国家科学研究中心（CNRS）、法国国家农业食品与环境研究院（INRAE）、格勒诺布尔国立高等理工学院（Grenoble INP）、格勒诺布尔地球科学研究所（IGE），法国格勒诺布尔市38000号

<b>摘要：</b>近数十年来，南极洲多个区域已从冰川质量平衡稳态转向质量亏损状态。为判定近期趋势是否超出自然变率的范畴，长期观测至关重要。本研究利用南极最早的大规模航空影像档案，构建了自20世纪30年代以来东南极沿岸21条外流冰川（outlet glacier）的独特观测记录。在吕佐夫-霍尔姆湾，研究结果显示自20世纪30年代以来冰面高程保持稳定，同时发现当地固定海冰环境出现弱化迹象。在坎普海岸、麦克罗伯逊海岸与英格里德·克里斯滕森海岸沿线，观测到自1937年和1960年以来冰川长期呈现适度增厚，其间伴随周期性减薄与年代际波动。所有区域的冰厚长期变化均与1940年以来的降雪量趋势相吻合。本研究表明，过去数十年间在陆地盆地观测到的冰面高程稳定与增长，属于至少持续一个世纪的长期趋势的一部分，同时凸显了在解读当前冰川动力学时，理解长期变化的重要性。

<b>数据说明：</b>本数据集包含由1937年至1973年间沿东南极沿岸（吕佐夫-霍尔姆湾（38°东经）至英格里德·克里斯滕森海岸（79°东经））拍摄的挪威与澳大利亚航空科考影像所生成的数字高程模型（DEM, Digital Elevation Model）、正射影像镶嵌图（orthophoto mosaics）、冰前端位置、表面流速以及冰厚变化量（dH）估算结果。其中数字高程模型与正射影像镶嵌图是采用Agisoft Metashape v.1.7.4软件的运动恢复结构（Structure-from-Motion, SfM）摄影测量技术生成的。本数据集还包含本文配图所用的代码。