Melting Glaciers and Geospatial Technology

We're the first generation to feel the impact of climate change and the last generation that can do something about it.'                                                                                                                                                                                                            – jay Inslee

 

• Glaciers Contain an Estimated 69 Percent of the World’s Fresh Water Supply.
• If every glacier and ice sheet on earth suddenly melted, global sea levels would rise by over 260 feet.
• During the peak of the last ice age, glaciers covered about a third of earth's land.

What is a glacier ?

Glaciers are made up of fallen snow that, over many years, compresses into large, thickened ice masses. Glaciers form when snow remains in one location long enough to transform into ice. What makes glaciers unique is their ability to move.

Presently, glaciers occupy about 10 percent of the world's total land area, with most located in polar regions like Antarctica, Greenland, and the Canadian Arctic.

Why they are important ?

Mountain glacier melt water provides drinking water, irrigation, power generation and other uses to communities downstream. They also play an integral role in regulating weather systems. For places with a dry and wet seasons, glaciers play a crucial role in storing up and slowly releasing water, making it available during the dry season when there is almost no rain. As the planet’s air conditioner, the polar ice caps impact weather and climate dynamics, such as the jet stream. Glaciers white surfaces reflect the sun’s rays, helping to keep our current climate mild. When glaciers melt, darker exposed surfaces absorb and release heat, raising temperatures.

Current condition

There was a time when they covered one third of the earth's land now glaciers are found on about 10 percent of earth's land area, with most of them found in the Arctic and Antarctica regions. In the past quarter-century glaciers in Antarctica have thinned and weakened. 24% of the ice in the western part of the continent is in danger of collapse. At some places they are thinned by 400 feet's. Without action, within the next fifty years the smaller glaciers will disappear completely and the larger ones will shrink significantly.

Role of remote sensing, GIS and photogrammetry

Remote sensing is the most suitable technique to analyse and study the large and small glaciers. Satellite remote sensing permits real-time, year-round and long-term studies. Studying glaciers from a wide range of remote sensing platforms and techniques has become an expanding field over the past decade. Using optical and microwave imaging a wide range of glacier observations can be performed. Among the most common are mapping of glacier extents, and determination of elevation and volume changes, surface flow velocity, and snow lines.

a) Mapping of glacier extents:

By mapping glaciers from satellite images, we can not only inventory the World’s glaciers, we can also analyse their rates of change and dynamic behaviour. Mapping include glacier attributes, such as area, length, slope, aspect, terminal environment (calving into the sea or lake, or terminating on dry land), elevation, and glacier classification.

                                                 Mapping and demarcating glaciers

b) Glacier elevation:

Glaciologists have become increasingly dependent on the use of Digital Elevation Models (DEMs) to analyze topographic landforms and as an input for further modelling. DEMs are particularly useful for monitoring and mapping both spatial and temporal change, as large areas can be modelled with only minimal field-based input. Differencing elevation data is a widely used method to document elevation and volume changes of glaciers.

c) Satellite imageries analysis

The satellite remote sensing gives possibility of universal, systematic and complex research of glaciers properties and changes. This is due to the fact that satellite remote sensing allows to cover efficiently the interesting regions and to study dynamically such important parameters, as the glacier area, terminus positions at the end of its location, firn line elevation, accumulation area, In turn these parameters allow calculation of glacier mass balance.

                                    DEM mosaic over Everest region of Nepal

d) Use of Unmanned Aerial Vehicle (UAV)

Satellite remote sensing is limited by spatial and temporal resolutions and the high costs involved in data acquisition. Unmanned aerial vehicle (UAV)-based glaciological studies are gaining pace in recent years due to their advantages over conventional remote sensing platforms. Recently UAV are used for monitoring glaciers in Himalayas. UAVs can bridge the gap between cumbersome field work and coarse resolution satellite imagery, and provide critical, detailed information about glacier change.

                                                     UAV for a closer look into glaciers

Summary

Glaciers are made up of fallen snow that, over many years, compresses into large, thickened ice masses. Mountain glacier melt water provides drinking water, irrigation, power generation and other uses to communities downstream. There was a time when they covered one third of the earth's land now glaciers are found on about 10 percent of earth's land area. Remote sensing is the most suitable technique to analyse and study the large and small glaciers. Satellite remote sensing permits real-time, year-round and long-term studies. DEM, UAV and GIS are playing critical role in study and analysis of glaciers.