Mountain glaciers are important climate indicators and glaciers are considered essential climate variables (ECV) by the Global Climate Observing System (GCOS). Understanding glacial change is necessary to predict future water availability, to assess potential hazards, and to estimate the contribution of glacier melt to sea level rise (Vaughan et al., 2013). In situ measurements are one of the key methods for improving our understanding of climate-glacier interactions. Field-based annual mass balance measurements, in particular, can be used as direct and immediate climate indicators. A combination of these measurements with hydro-meteorological information provides an excellent basis for improving understanding of the relationships between glaciers and the local climate, as well as estimates of glacial and snow contribution to river discharge (e.g. Anderson et al., 2010). Such information is important for policy makers, planners, and industry to estimate, and adapt to, downstream water availability, for example for hydropower plants, irrigation, or drinking water (e.g. Salzmann, Huggel, Rohrer, & Stoffel, 2014). They are also important to raise awareness about and sensitise local people to the changes in the glaciers that feed their rivers. Field measurements are essential to understand glacial dynamics and processes and to assess possible risks, such as glacial lake outburst floods (GLOFs) (Mool, Bajracharya, & Joshi, 2001).
Better understanding of what is happening to the glaciers requires a comprehensive research strategy that includes in situ measurements, remote sensing techniques, and modelling approaches. In situ measurements provide the necessary information for understanding large-scale and small-scale processes as they enable ground truthing and can be used for calibrating both remotely-sensed information and modelled output. Remote sensing analyses are used in models to scale up results to larger areas and to cross check field measurements with an independent method. The models can then be used to project future scenarios, for example for water availability. However, in the Himalayan region frequent cloud cover during the monsoon and seasonal snow cover make it difficult to obtain suitable freely available satellite images for small-scale applications. In addition, the very steep mountainous terrain decreases data accuracy and mountains often obscure parts of the area of interest. Thus ground-based information is necessary to georectify satellite images and verify data. But the availability of such in situ data in the Himalayan region is low (Bolch et al., 2012; Kääb, Berthier, Nuth, Gardelle, & Arnaud, 2012) due to the challenging nature of glacier fieldwork, the cost of expeditions, and the high level of fitness and experience required by the monitoring team. Glacier mass balance monitoring programmes have been established in many major mountain ranges in the world (Zemp, Hoelzle, & Haeberli, 2009; Nussbaumer et al., 2017), however, the challenges in carrying out fieldwork are manifold, and depend on the climate, topography, available financial and human resources, and infrastructure in the specific environment.
Compared to most other mountain ranges, the Himalayas have very few long-term glacier monitoring programmes. In order to fill the data gap in the Himalayan region, it is important to establish consistent and long-term mass balance measurements. This working paper discusses the nature, challenges, and differences of field work on mountain glaciers in different parts of the world, and provides recommendations for implementing organisations, academics, and funding agencies to estimate the human resources, required skills, and logistic support necessary to set up and maintain a sustainable long-term glacier monitoring programme to produce consistent and continuous data in the Himalayas.
The report was co-funded by the Royal Norwegian Embassy in Nepal.