From local glacier surface mass balance observations to regional climate simulations : investigating current glacier trends in Nepal

4-6 months from February to July, 2026

**Context

Glaciers in High Mountain Asia (HMA) are a crucial water resource for downstream communities and are strongly affected by global warming (Immerzeel et al., 2020). Variations in glacier mass in HMA arise from climatic forcing that affect both temperature and precipitation, which ultimately impact their mass balance (Sakai and Fujita, 2017). Recent advances in remote sensing, in particular with the availability of DEMs from multiple sensors that allowed regional scale application of the geodetic mass balance methods, have significantly improved our understanding of region-wide glacier mass changes in HMA (e.g., Hugonnet et al., 2021). However, field-based measurements and long-term, high-quality meteorological datasets remain essential for better characterizing the relationship between glacier mass balance and climate in this region (Khadka et al., 2024). In the Himalaya, located south and east of the HMA and including Nepal, most of the precipitation occurs during summer monsoons, whereas winters are drier and very cold. Occasional snowfall can also occur during the pre- and post-monsoon periods (Ménégoz et al., 2025). Thus, Nepal glaciers are specific in the sense that both accumulation and melting predominantly occur during the monsoon season (JJAS), with high snowfall rates at high elevation (above 5000 - 6000 m) and strong melting at the lower parts of the glaciers.

**Objectives

The main objective of this internship is to take advantage of (i) a new regional climate modelling conducted with MAR (e.g., Beaumet et al., 2021, for an application to the Alps) for the last 40yrs on the Central Himalaya at a 7x7 km resolution and (ii) a unique field based surface mass balance (SMB) dataset, to investigate mass balance patterns at the Mera glacier (Khumbu Valley, Nepal), and their underlying causes.

First task : extract and process Glacioclim data for the Mera Glacier to make them ready for comparison with modeled SMB (elaborate and update following Khadka et al., 2024).
The Mera glacier is a summer-accumulation type glacier located in Central Himalaya, and its mass balance has been continuously monitored since 2007, at least once a year in the fall, yielding one of the longest mass balance continuous field-based series in the Nepal Himalayas (Glacioclim network, https://glacioclim.osug.fr/, Wagnon et al., 2021).

Second task : evaluate the performance of MAR in reproducing the SMB of the Mera glacier.
Tuned MAR simulations for Central Himalaya has been already produced and evaluated : although some biases have been identified (Santolaria-Otín et al., in prep), MAR outputs will represent an improvement over the available reanalysis datasets (only gridded at coarse spatial resolution) for investigating SMB of Central Himalaya glaciers. This task will involves : (i) extract MAR SMB data and perform comparisons with field observations, (ii) discuss such comparisons in the frame of identified biases of MAR, (iii) discuss the major physical processes governing the inter-annual variability and trend of SMB for the Mera Glacier, considering the link between mass balance with temperature, precipitation, albedo, etc…

Third task : extend the study spatially and temporally, if the model is shown to well represent SMB for the Mera glacier for the period spanning 2007-2024 where field observations are available.
The student will compare SMB extracted for the Mera Glacier with modelled SMB on other Central Himalaya glaciers (e.g., Arndt and Schneider, 2023) and provide a regional estimate of SMB changes at the scale of the whole Nepal area. The student will also evaluate the MAR SMB output for Mera glacier over the last 40yrs, addressing the following questions : how did Mera SMB vary since 1980 ? Which processes (accumulation, surface melting) and atmospheric forcing (e.g., precipitation, temperature, radiation) have been driving Mera SMB over the last 4 decades ? Did these drivers change over time ?

**References

Arndt, A. and Schneider, C. : Spatial pattern of glacier mass balance sensitivity to atmospheric forcing in High Mountain Asia, J. Glaciol., 69, 1616–1633, https://doi.org/10.1017/jog.2023.46, 2023.
Hugonnet, R., McNabb, R., Berthier, E., Menounos, B., Nuth, C., Girod, L., Farinotti, D., Huss, M., Dussaillant, I., Brun, F., and Kääb, A. : Accelerated global glacier mass loss in the early twenty-first century, Nature, 592, 726–731, https://doi.org/10.1038/s41586-021-03436-z, 2021.
Immerzeel, W. W., Lutz, A. F., Andrade, M., Bahl, A., Biemans, H., Bolch, T., Hyde, S., Brumby, S., Davies, B. J., Elmore, A. C., Emmer, A., Feng, M., Fernández, A., Haritashya, U., Kargel, J. S., Koppes, M., Kraaijenbrink, P. D. A., Kulkarni, A. V., Mayewski, P. A., Nepal, S., Pacheco, P., Painter, T. H., Pellicciotti, F., Rajaram, H., Rupper, S., Sinisalo, A., Shrestha, A. B., Viviroli, D., Wada, Y., Xiao, C., Yao, T., and Baillie, J. E. M. : Importance and vulnerability of the world’s water towers, Nature, 577, 364–369, https://doi.org/10.1038/s41586-019-1822-y, 2020.
Khadka, A., Brun, F., Wagnon, P., Shrestha, D., and Sherpa, T. C. : Surface energy and mass balance of Mera Glacier (Nepal, Central Himalaya) and their sensitivity to temperature and precipitation, J. Glaciol., 70, e80, https://doi.org/10.1017/jog.2024.42, 2024.
Ménégoz M., Brun F., Wagnon P. : Glaciers in the high mountains of Asia in the face of climate change, Encyclopedia of the Environment, Accessed October 23, 2025, url : https://www.encyclopedie-environnement.org/en/climate/glaciers-in-the-high-mountains-of-asia-in-the-face-of-climate-change/.
Sakai, A. and Fujita, K. : Contrasting glacier responses to recent climate change in high-mountain Asia, Sci Rep, 7, 13717, https://doi.org/10.1038/s41598-017-14256-5, 2017.
Wagnon, P., Brun, F., Khadka, A., Berthier, E., Shrestha, D., Vincent, C., Arnaud, Y., Six, D., Dehecq, A., Ménégoz, M., and Jomelli, V. : Reanalysing the 2007–19 glaciological mass-balance series of Mera Glacier, Nepal, Central Himalaya, using geodetic mass balance, Journal of Glaciology, 67, 117–125, https://doi.org/10.1017/jog.2020.88, 2021.