Bedmap Himalayas - Reconnaissance

Lead Research Organisation: NERC British Antarctic Survey
Department Name: Science Programmes

Abstract

High in the Himalayan mountains thousands of glaciers flow slowly downhill, fed in the upper reaches by monsoon and winter snowfall while melting away in the warmer temperatures at the glacier snouts, to flow as meltwater down into Asia's major rivers -the Ganges, Indus and Brahmaputra. If snowfall equals melt the glaciers remain the same size, but the steady runoff of meltwater through the dry months keeps the rivers flowing. During droughts when the monsoon rains and snowfall fail, the melt continues, and in hot weather it increases, supplying water to the plains below when it is most needed.

This water is used by around 800 million people for drinking, irrigated agriculture, hydropower and industry. In the Indus catchment, 237 million people are rated as heavily dependent on glacier runoff for irrigation in the dry season, and this population is growing by 4 million per year. Meanwhile, from years 2003-2009, the Himalayas lost around 26 cubic kilometres of ice per year as snowfall has not kept up with melt. For the populations of some river basins, glacier runoff is a vital resource, but its volume is remarkably poorly known because it has never been surveyed. Reportedly fewer than ten of the 20,000 to 40,000 glaciers have direct thickness measurements, and volume estimates from indirect methods (like estimating it from the surface area) range from 1670 to 6500 cubic kilometres. This uncertainty makes it difficult to predict the future of this vulnerable but highly valuable water resource.

It is not easy to measure the glacier volume for several reasons. We can use radar like an x-ray system to see through glaciers to their beds and measure their thickness, but in the Himalayas, many glaciers are covered in a layer of scree that has fallen from the steep walls of the surrounding mountains. The stones in this scree are about the size of the radar wavelengths usually used for ice surveys in polar regions, so they scatter the radar signal rather than letting it pass through into the ice. Also, water in the melting glacier tongues absorbs the radar energy, preventing it from reaching the bed. Even if we have a suitable radar that could see through these glaciers, just getting to them is difficult because the mountain ranges are extremely rugged and often lie along national borders that are disputed by the countries on either side.

In this project, we will work with local experts from the International Centre for Integrated Mountain Development (ICIMOD) in Kathmandu to take a low-frequency radar system to a scree-covered Nepali glacier and, by varying the frequency and power, work out how to see the glacier bed even in these challenging conditions. With this knowledge, we can in future design a radar for a small aircraft that can survey large areas quickly and easily.

We will also work with ICIMOD's hydrologists, glaciologists, geographers and regional experts to design an airborne survey for the Himalayan region that maximises glacier coverage while minimising flying costs, giving a good sample of the regional ice distribution, prioritising the most runoff-dependent river catchments and respecting boundaries and politically sensitive regions. This will likely span the glaciated areas of Nepal, India, Pakistan, China and Bhutan. To be allowed to conduct a large-scale survey, it is vital that we establish collaborations with scientists and government agencies in these countries. We will begin to cultivate these collaborations through visiting contacts in Kathmandu and another ICIMOD office in Islamabad, Pakistan. With a logistics expert, we also plan to select and visit a mountain airstrip to check whether it is suitable for use as a logistics hub for an airborne survey of the region's glaciers. Together, these activities will pave the way for a major advance in our understanding of a water resource relied upon by hundreds of millions of people.

Planned Impact

By developing a method for surveying Himalayan ice volumes, we are getting closer to a major dataset that, along with regional climate predictions, is key to predicting the future supply of glacial runoff to downstream river systems. In the medium term, this will benefit academics in disciplines including glaciology, hydrology, water resource management, natural hazards (particularly drought), monitoring and predicting impacts of climate change, agriculture, hydroelectric power and social and economic development. Most importantly though, this should ultimately benefit policy makers in the governments of the downstream countries - Afghanistan, Bhutan, China, India, Nepal, Pakistan, Bangladesh and Myanmar - and particularly Pakistan, where reliance on runoff is greatest and pressure on water resources is acute. In the Indus drainage basin alone, this amounts to 237 million people.

Improved predictions of water supply are likely to be particularly important for hydropower industries and the irrigated agriculture sector. A quarter of Bhutan's national income comes from hydropower on glacier-fed rivers and the population of the Indus basin is fed by the world's largest irrigated farming system, that already extracts over 95% of the available river discharge. Pakistan's population is currently classed as 'water stressed' (1400 cubic metres/person/year), but the population is predicted to increase to 319 million in little over a decade, and 383 million by 2050 (Laghari et al., 2012). Even with an unchanging river discharge, this will put the population in 'chronic scarcity' (900 cubic metres) by 2030 (National Research Council, 2012). However, climate predictions suggest that the Indus and Brahmaputra summer and late spring discharge will be reduced "consistently and considerably" by around the middle of this century - such reduced runoff would reduce the number of people who could be fed in these basins by 35 million and 26 million people respectively (Immerzeel et al., 2010).

To summarise, this proposal is the first step towards developing the NERC capability to survey regional mountain-glacier ice volumes. This is important because large populations depend on these glaciers to sustain their water supply. Seasonal loss of supply would jeopardise food and power supplies on a national scale, with potentially serious political, economic and humanitarian consequences. The potential beneficiaries outside the immediate academic field number in the hundreds of millions and include significant industrial sectors and governments.


National Research Council. Himalayan Glaciers: Climate Change, Water Resources, and Water Security. Washington, DC: The National Academies Press, 2012.

Immerzeel, W. W., van Beek, L. P. H. & Bierkens, M. F. P. Science 328, 1382-1385 (2010).

Laghari, A. N., Vanham, D., and Rauch, W.: The Indus basin in the framework of current and future water resources management, Hydrol. Earth Syst. Sci., 16, 1063-1083, doi:10.5194/hess-16-1063-2012, 2012.

Publications

10 25 50
 
Description I have determined how well a ground-based radar system can detect and map the bed of debris-covered Himlayan glaciers at a range of frequencies. I found that a 5 MHz dipole system (operating at +-2.5 kV transmit power) is well suited because it gives a strong and unambiguous bed reflection through ~270 m of ice. Higher frequencies (10 MHz, 20 MHz) detect the bed but returns of similar strength are present as abundant clutter from the surrounding valley walls and rough glacier surface. By using the lower frequency and conducting a combination of long- and cross-profiles, it is possible to distinguish the bed echo from clutter. Best results came from amplifying the return signal and averaging around 100 stacks. Noise was reduced slightly by averaging 500 stacks, but little extra improvement came from further averaging.

I have also established collaborations with Nepal-based research centres ICIMOD and Kathmandu University and will return for another joint field survey in April 2016.
Exploitation Route These findings can be used to design further glacier ice thickness surveys on debris-covered glaciers anywhere in the world. The parameters that I tested define the physical size of the system needed and the dwell time required at each site.Update: I have used these findings to design and build an airborne version of the radar that I tested in this project, and have gained funding to conduct an initial Himalayan test survey in India, in conjunction with Indian partners.
Sectors Environment

URL https://www.bas.ac.uk/project/bedmap-himalayas/
 
Description I have used this pilot study as the basis to apply for and win funding 1) to build an test an airborne version of the radar system used in this project, which is near completion, and 2) to carry out an initial glacier ice volume survey in the Indian Himalayas as part of the BAS Official Development Assistance component of its National Capability funding, to take place over the next two years. These follow directly from the success of the field tests done in this project. The rationale for the Himalayan survey is to reduce uncertainties in mountain water resources, which are relevant to hydropower, agriculture and many other domestic and industrial water uses in South Asia. Additionally, I have been invited to use this airborne system to contribute to an ice-core climate study on the island of South Georgia (2019/2020 season) and a major NERC-NSF thematic programme studying Thwaites Glacier, Antarctica, in the 2020/21 season, with possible additional testing in Alaska with the US partner prior to this survey. Update: We now have a built-and-tested system ready to go to the Himalayas in late 2019.
First Year Of Impact 2017
Sector Agriculture, Food and Drink,Energy
Impact Types Societal,Policy & public services

 
Description Polar Expertise - Supporting Development (Bedmap Himalayas section)
Amount £98,000 (GBP)
Funding ID NEB1348 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 04/2017 
End 04/2020
 
Title Bedmap AIR 
Description Using funding from the British Antarctic Survey, we are now developing an airborne version of the radar system that I tested in this grant. The results of the research undertaken here are directly informing the design of this airborne system. It will be a helicopter-borne underslung load transporting a 5 MHz (low frequency) ice sounding radar. We are currently working on the aerodynamic behaviour of the instrument design, and have applied for additional funding to complete the construction and conduct full field tests of this Bedmap AIR. This was the stated desired outcome from this award. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact I have requests from colleagues in the US and India to deploy this survey instrument in Antarctica and the India Himalayas, with foci on research into ice sheet/sea-level-rise and Asian freshwater resources. This instrument has considerable potential. 
 
Title Bedmap AIR 
Description We have now built and tested our airborne radar system, based on the research carried out under this project. We will be deploying it in the Nepal Himalayas in October 2019 to conduct glacier ice thickness surveys. 
Type Of Material Improvements to research infrastructure 
Year Produced 2018 
Provided To Others? No  
Impact We have developed the institutional capability to survey potentially any glacier in the world, because our system is helicopter-portable and will penetrate through the thickest ice. 
URL https://www.bas.ac.uk/project/bedmap-himalayas/
 
Description Bedmap Himalayas KU collaboration 
Organisation Kathmandu University
Country Nepal 
Sector Academic/University 
PI Contribution I invited a Kathmandu University postgraduate student to join our research expedition and trained the student in radar field survey. I am collaborating with The Energy and Resources Institute (TERI), New Delhi India on a research proposal to conduct large-scale ice thickness surveys in the Indian Himalayas (result pending) based on the results of this grant.
Collaborator Contribution Our partner sent a postgraduate student to help us with our field survey and also helped us to obtain the necessary research permits.
Impact Data collected in this study is contributing to postgraduate research at Kathmandu University and field experience gained by the student has contributed to in-country capacity building.
Start Year 2015
 
Description Bedmap Himalayas KU collaboration 
Organisation The Energy and Resources Institute
Country India 
Sector Charity/Non Profit 
PI Contribution I invited a Kathmandu University postgraduate student to join our research expedition and trained the student in radar field survey. I am collaborating with The Energy and Resources Institute (TERI), New Delhi India on a research proposal to conduct large-scale ice thickness surveys in the Indian Himalayas (result pending) based on the results of this grant.
Collaborator Contribution Our partner sent a postgraduate student to help us with our field survey and also helped us to obtain the necessary research permits.
Impact Data collected in this study is contributing to postgraduate research at Kathmandu University and field experience gained by the student has contributed to in-country capacity building.
Start Year 2015
 
Description Presentation of results planned (abstract submitted) at International Glaciological Society meeting 'Five Decades of Radioglaciology', Stanford, USA, July 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I have submitted the following abstract to present the results of this project and the next steps taken towards a full airborne survey capability:

"Measurements of glacier thickness are very rare in most mountain ranges because radar and seismic field surveys are laborious, slow and expensive, particularly in high mountains and on debris covered glaciers. Indirect modelling approaches to estimating glacier volumes from the local to the global scale have been developed but their dependence on other poorly known parameters such as surface mass balance, plus the lack of observations for constraint, mean that the uncertainties are large. Estimates of the ice volume in High Mountain Asia, for example, vary by about a factor of 2. Low-frequency radar systems towed over snow are routinely used to survey the thickest areas of the ice-sheets but the rough surface of many high-mountain glaciers make over-snow towing impossible. We have adapted a low frequency ice-sheet system for airborne survey by helicopter over high, debris covered mountain glaciers, and we report here the results of field and airborne testing. This new system is capable of transforming our knowledge of glacier thickness on the mountain-range scale, and can therefore greatly reduce uncertainty in predictions of the future summer water supply to glacierised river catchments."
Year(s) Of Engagement Activity 2019
URL https://www.igsoc.org/
 
Description Up-coming presentation of results at international conference, European Geophysical Union 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I have been accepted to present these results at one of the two premier international geophysical science conferences. This will be to other specialists in the field, the ideal audience for the methodological advances made.
Year(s) Of Engagement Activity 2017