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Bedmap Himalayas - Reconnaissance

喜马拉雅山床图 - 勘察

基本信息

批准号：
NE/L013258/1
负责人：
Hamish Pritchard
金额：
$ 5.07万
依托单位：
British Antarctic Survey
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FL013258%2F1
关键词：
Bedmap Himalayas Reconnaissance

项目摘要

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.

在喜马拉雅山脉的高处，成千上万的冰川缓慢地向山下流动，在上游受到季风和冬季降雪的滋养，同时在冰川鼻的温暖温度下融化，作为融水流入亚洲的主要河流-恒河，印度河和雅鲁藏布江。如果降雪等于融化，冰川保持不变的大小，但在干旱的月份，融化的水稳定的径流使河流保持畅通。在季风降雨和降雪不足的干旱期间，冰川继续融化，在炎热的天气里，冰川融化会增加，在最需要的时候为下面的平原供水。大约8亿人使用这些水来饮用，灌溉农业，水力发电和工业。在印度河流域，有2.37亿人在旱季严重依赖冰川径流灌溉，而且这一人口每年增长400万。与此同时，从2003年到2009年，喜马拉雅山每年损失约26立方公里的冰，因为降雪量没有跟上融化的速度。对于一些河流流域的人口来说，冰川径流是一种重要的资源，但由于从未进行过调查，因此对其数量知之甚少。据报道，在20，000至40，000个冰川中，只有不到10个冰川有直接的厚度测量，间接方法（如从表面积估计）的体积估计为1，670至6，500立方公里。这种不确定性使得很难预测这种脆弱但非常宝贵的水资源的未来。由于以下几个原因，测量冰川体积并不容易。我们可以像使用X射线系统一样使用雷达来透视冰川，并测量其厚度，但在喜马拉雅山脉，许多冰川都覆盖着一层从周围山脉陡峭的墙壁上落下的碎石。碎石中的石头大小与通常用于极地冰层调查的雷达波长差不多，所以它们散射雷达信号，而不是让它通过冰层。此外，融化的冰川舌中的水吸收了雷达能量，阻止了它到达河床。即使我们有合适的雷达可以穿透这些冰川，到达它们也很困难，因为山脉极其崎岖，而且经常沿着两国有争议的国界。在这个项目中，我们将与位于加德满都的国际山地综合开发中心（ICIMOD）的当地专家合作，将低频雷达系统应用到碎石上，在尼泊尔的冰川覆盖，并通过改变频率和功率，工作如何看到冰川床，即使在这些具有挑战性的条件。有了这些知识，我们将来可以为小型飞机设计一种雷达，它可以快速、轻松地探测大面积区域。我们还将与ICIMOD的水文学家，冰川学家，地理学家和区域专家合作，为喜马拉雅地区设计一项空中调查，最大限度地扩大冰川覆盖范围，同时最大限度地减少飞行成本，提供区域冰分布的良好样本，优先考虑最依赖径流的河流流域，并尊重边界和政治敏感地区。这将可能跨越尼泊尔、印度、巴基斯坦、中国和不丹的冰川地区。为了能够进行大规模的调查，我们必须与这些国家的科学家和政府机构建立合作关系。我们将开始通过在加德满都和在巴基斯坦伊斯兰堡的另一个山地发展中心办事处的访问接触来培养这些合作。我们还计划与一名物流专家一起选择并访问一个山区简易机场，以检查它是否适合用作该地区冰川空中调查的物流枢纽。这些活动将共同为我们对数亿人所依赖的水资源的理解取得重大进展铺平道路。