A deep learning reconstruction of mass balance series for all glaciers in the French Alps: 1967–2015

[摘要] Glacier mass balance (MB) data are crucial to understanding and quantifying the regional effects of climate on glaciers and the high-mountain water cycle, yet observations cover only a small fraction of glaciers in the world. We present a dataset of annual glacier-wide mass balance of all the glaciers in the French Alps for the 1967–2015 period. This dataset has been reconstructed using deep learning (i.e. a deep artificial neural network) based on direct MB observations and remote-sensing annual estimates, meteorological reanalyses and topographical data from glacier inventories. The method's validity was assessed previously through an extensive cross-validation against a dataset of 32 glaciers, with an estimated average error (RMSE) of 0.55  m w . e . a - 1 , an explained variance ( r 2 ) of 75 % and an average bias of −0.021   m w . e . a - 1 . We estimate an average regional area-weighted glacier-wide MB of −0.69 ± 0.21 (1 σ )  m w . e . a - 1 for the 1967–2015 period with negative mass balances in the 1970s ( −0.44   m w . e . a - 1 ), moderately negative in the 1980s ( −0.16   m w . e . a - 1 ) and an increasing negative trend from the 1990s onwards, up to −1.26   m w . e . a - 1 in the 2010s. Following a topographical and regional analysis, we estimate that the massifs with the highest mass losses for the 1967–2015 period are the Chablais ( −0.93   m w . e . a - 1 ), Champsaur ( −0.86   m w . e . a - 1 ), and Haute-Maurienne and Ubaye ranges ( −0.84   m w . e . a - 1 each), and the ones presenting the lowest mass losses are the Mont-Blanc ( −0.68   m w . e . a - 1 ), Oisans and Haute-Tarentaise ranges ( −0.75   m w . e . a - 1 each). This dataset – available at https://doi.org/10.5281/zenodo.3925378 ( Bolibar et al. ,  2020 a ) – provides relevant and timely data for studies in the fields of glaciology, hydrology and ecology in the French Alps in need of regional or glacier-specific annual net glacier mass changes in glacierized catchments.

[学科分类] 眼科学