Mass, volume, models: Listening to glaciers

Written by H C Nainwal

THE RECENT tragedy in Uttarakhand brought a lot of focus on Himalayan glaciers. But these glaciers have been a subject of intense discussion for the last few decades now because of global warming.

Melting of glaciers is one of the most dramatic impacts of rising global temperatures, and much of this is playing out in the Himalayas, where the winter period has been noticeably reducing steadily, and so is the amount of snowfall received during the winter season.

There are close to 10,000 big and small glaciers in the Himalayas. Like the other glaciers of the globe, most of them are retreating because of the rise in temperatures. Many of these glaciers are retreating at an average rate of 5 to 20 metres a year.

In India, the study of glaciers began in the 1940s, thanks to the efforts of the Geological Survey of India, which carried out the first research projects and measurements. Now, of course there are several government departments, institutions and universities that are involved in the study of Himalayan glaciers.

The study of glaciers requires a very multidisciplinary approach. It combines the knowledge of geology, physics, hydrology, meteorology, mathematical modelling, and many other fields. It also needs the help of technological tools like remote sensing and Geographic Information System. There are several aspects of glaciers that need to be studied to get a clue about their behaviour, and to understand their dynamics. These include mass balance (ablation/melting), estimation of volume, snow cover mapping, hydrology, geochronological studies, modelling and sensitivity, GLOF (Glacial Lake Outburst Floods), meteorology, black carbon, and aerosol studies.

The Ganga has two major tributaries — Alaknanda and Bhagirathi. These two rivers originate from different glaciers. Bhagirathi originates from the Gangotri glacier while Alaknanda comes from the Satopanth glacier. The 13-km long Satopanth glacier is located in the Upper Alaknanda basin and the snout of the glacier is situated about 15 km upstream of Badrinath. Since 2005, I have been working on the Satopanth glacier, studying its dynamics, mass balance (through field-based techniques), surface velocity, and the impacts of aerosols and black carbon.

Our field visits happen between April and October. In the winter season, most of these areas become inaccessible. We usually set up a base camp near the snout of the glacier and then trek upwards for measurements and collection of data. We stay at these locations for several weeks. A lot of support staff, like porters, accompany us to these field visits.

We have also installed an automatic weather station near the snout of the Satopanth glacier in order to collect meteorological data of the basin. Modern technology tools like Ground Penetrating Radar (GPR) and differential Global Positioning System (DGPS) give us very precise measurements about the changes in the glaciers. A lot of measurements are done through remote-sensing techniques as well, using our satellites in space.

The study of glaciers has improved considerably in India in the last few years and the number of people studying them has also increased. But this is still not adequate. For example, there are very few automatic weather stations installed near the glaciers. We need much better infrastructure and more human resources.

What is also required is better coordination between the different teams working on the Himalayan glaciers. As I mentioned earlier, glaciology is multidisciplinary. There are lots of different agencies involved, and often they work separately. What we need is that every project or scientific group should complement the works of the others. There is a need to establish a National Institute of Glaciology to study all aspects of Himalayan glaciers in a very holistic manner.

Also, we need to set up a framework of representative glaciers along and across the Himalayas, and then study them comprehensively over prolonged periods. Right now, a typical research project lasts for about three years. Many of them do get extended, but we require long-term data, over several years or decades to be able to map their behaviour accurately. Therefore, there is a need to initiate long-term in-situ measurement for mass balance and dynamics of such representative glaciers.

Thanks to the efforts of the last couple of decades, we now have good quality data on some of the Himalayan glaciers. But this needs to improve further.

The glaciers are the biggest sources of fresh water, and hundreds of millions of people depend on the rivers that source their water from them. Therefore, there is a need to understand the complex Himalayan system by creating field, logistics and communication system, ensuring human resource development, and interface at national, regional and international levels.

Nainwal is a glaciologist at Hemwati Nandan Bahuguna Garhwal University in Srinagar, Uttarakhand.

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