A team of us, led by Christophe Kinnard, just published a paper synthesising a bunch of work done on a small glacier in the Arid Andes.

Kinnard, C., Ginot, P., Surazakov, A., Macdonell, S., Nicholson, L.I., Patris, N., Rabatel, A., Rivera, A. and Squeo, F. (2020) Mass-balance and climate history of a high-altitude glacier, Desert Andes of Chile. Frontiers in Earth Science, 8, 40.

Glaciers in the dry Chilean Andes provide important ecological services, yet their mass balance response to past and ongoing climate change is not that well studied. The new paper uses glaciological, geodetic, and ice core observations to examine recent (2002–2015), historical (1955–2005), and past (<1900) mass balance history of Guanaco Glacier (29.34°S, >5000 m). The work was done by CEAZA and its partners, over a number of years, including those when I worked at CEAZA leading the glacier research group, which is now led by Shelley MacDonell.

My contribution to writing this paper was lightweight, but its great to see it out there, especially as I was involved in the mass balance work and the ice coring project of the Guanaco Glacier.

The main findings are summarised in the abstract:

1. Analysis of mass balance and meteorological data since 2002 suggests that mass balance is currently mostly sensitive to precipitation variations, while low temperatures, aridity and high solar radiation and wind speeds cause large sublimation losses and limited melting.
2. Mass balance reconstructed by geodetic methods shows that Guanaco Glacier has been losing mass since at least 1955, and that mass loss has increased over time until present.
3. An ice core recovered from the deepest part of the glacier in 2008 revealed that the glacier is cold-based with a -5.5°C basal temperature and a warm reversal of the temperature profile above 60-m depth attributed to the recent atmospheric warming trend. Detailed stratigraphic and stable isotope analyses of the upper 20 m of the core revealed seasonal cycles in the delta¹⁸O and delta ²H records with periods varying between 0.5 and 3 m. w.e. a^–1. Deuterium excess values larger than 10‰ suggest limited post-depositional sublimation, while the presence of numerous refrozen ice layers indicate significant summer melt. Tritium concentration in the upper 20 m of the core was very low, while ²¹⁰Pb was undetected, indicating that the glacier surface in 2008 was at least 100 years old.
4. Taken together, these results suggest that Guanaco Glacier formed under drastically different climate conditions than today, when humid conditions caused high accumulation rates, reduced sublimation and increased melting. Reconstruction of mass balance based on correlations with precipitation and streamflow records show periods of sustained mass gain in the early 20th century and the 1980s, separated by periods of mass loss. The southern migration of the South Pacific Subtropical High over the course of the 20th and 21st centuries is proposed as the main mechanism explaining the progressive precipitation starvation of glaciers in this area.

Here is a list of other works mostly produced by CEAZA and its partners on these small arid zone glaciers and their surroundings:

• Réveillet, M.,MacDonell, S., Gascoin, S., Kinnard, C., Lhermitte, S., Schaffer, N. 2020. Impact of forcing on sublimation simulations for a high mountain catchment in the semiarid Andes. The Cryosphere, 14, 147–163. https://doi.org/10.5194/tc-14-147-2020
• Rowe, P., Cordero, R., Warren, S., Stewart, E., Doherty, S., & Pankow, A., Schrempf, M., Casassa, G., Carrasco, J., Pizarro, J., MacDonell, S., Damiani, A., Lambert, F., Rondanelli, R., Huneeus, N., Fernandoy, F., Neshyba, S. (2019). Black carbon and other light-absorbing impurities in snow in the Chilean Andes. Scientific Reports, 9(1). doi: 10.1038/s41598-019-39312-0
• Schaffer, N., MacDonell, S., Réveillet, M., Yáñez, E., & Valois, R. (2019). Rock glaciers as a water resource in a changing climate in the semiarid Chilean Andes. Regional Environmental Change, 19(5), 1263-1279. doi: 10.1007/s10113-018-01459-3
• Azócar, G. F., Brenning, A., & Bodin, X. (2017). Permafrost distribution modelling in the semi-arid Chilean Andes. The Cryosphere, 11(2), 877.
• Sinclair, K. & MacDonell, S. (2016). Seasonal evolution of penitente glaciochemistry at Tapado Glacier, Northern Chile. Hydrol. Process., 30(2), 176-186.
• Nicholson L. I., P?tlicki M., Partan B., and MacDonell S. (2016). 3-D surface properties of glacier penitentes over an ablation season, measured using a Microsoft Xbox Kinect. The Cryosphere, 10(5), 1897.
• Arenson, L. U., Jakob, M., & Wainstein, P. (2015). Effects of dust deposition on glacier ablation and runoff at the Pascua-Lama Mining Project, Chile and Argentina. In Engineering Geology for Society and Territory-Volume 1 (pp. 27-32). Springer, Cham.
• Abermann, J., Kinnard, C., & MacDonell, S. (2014). Albedo variations and the impact of clouds on glaciers in the Chilean semi-arid Andes. Journal Of Glaciology, 60(219), 183-191.
• MacDonell, S., Kinnard, C., Mölg, T., Nicholson, L., & Abermann, J. (2013). Meteorological drivers of ablation processes on a cold glacier in the semi-arid Andes of Chile. The Cryosphere, 7(5), 1513-1526. http://dx.doi.org/10.5194/tc-7-1513-2013
• Gascoin, S., Lhermitte, S., Kinnard, C., Bortels, K., & Liston, G. E. (2013). Wind effects on snow cover in Pascua-Lama, Dry Andes of Chile. Advances in Water Resources, 55, 25-39.
• Gascoin, S., Kinnard, C., Ponce, R., Macdonell, S., Lhermitte, S., & Rabatel, A. (2011). Glacier contribution to streamflow in two headwaters of the Huasco River, Dry Andes of Chile. The Cryosphere, (5), 1099-1113.
• Rabatel, A., Castebrunet, H., Favier, V., Nicholson, L., & Kinnard, C. (2011). Glacier changes in the Pascua-Lama region, Chilean Andes (29 S): recent mass balance and 50 yr surface area variations.
• Azócar, G. F., & Brenning, A. (2010). Hydrological and geomorphological significance of rock glaciers in the dry Andes, Chile (27–33 S). Permafrost and Periglacial Processes, 21(1), 42-53.
• Nicholson, L., Marín, J., Lopez, D., Rabatel, A., Bown, F., & Rivera, A. (2009). Glacier inventory of the upper Huasco valley, Norte Chico, Chile: glacier characteristics, glacier change and comparison with central Chile. Annals of Glaciology, 50(53), 111-118.

So much sciencing!