Fig. 4: Long-term trends in surface processes affecting glacier runoff.
From: Poleward shift of subtropical highs drives Patagonian glacier mass loss
Time series of annual (a) ablation zone fraction (%), i.e., relative to the total glacier area, (b) rainfall fraction (%), i.e., relative to the glacier-integrated total precipitation, (c) firn refreezing capacity (%), i.e., the fraction of total melt and rainfall retained or refrozen in firn, for the period 1940–2023. MAR and RACMO data at 500 m are shown as green lines and blue bands, respectively. Long-term trends (1940-2023) derived from MAR are shown as dashed lines. Correlation between anomalies in glacier near-surface temperature (T2m, relative to 1960–1989) and (d) ablation zone fraction, (e) rainfall fraction, and (f) firn refreezing capacity from MAR (green dots) and RACMO (blue dots) at 500 m. (g–i) same as (d–e) but correlated to surface runoff. In (d–i) linear regression and relevant statistics, i.e., number of records (N), slope (a), intercept (b), and correlation (r), include both MAR (84 years) and RACMO (45 years) data sets.
