IMAGING

How ISRO used satellite remote-sensing to analyse glacial lakes in Himalayas

The Indian Space Research Organisation (ISRO) recently released satellitedata-based analysis on expansion of glacial lakes in the catchments of Indian Himalayan river basins. This is the latest among a clutch of studies on glacial lakes that have highlighted the risks of glacial lake outburst floods (GLOFs), and their impact on infrastructure and settlements downstream of such lakes.

What did ISRO’s analysis reveal?

ISRO’s analysis looked at satellite data archives spanning the past four decades to assess changes in the glaciated environment. Long-term satellite imagery covering the catchments of Indian Himalayan river basins — spread over India, Nepal, Tibet, and Bhutan — is available from 1984 onwards, till 2023. ISRO’s data has indicated significant expansion in the size of glacial lakes.

Of the 2,431 lakes larger than 10 hectares (identified during 2016-17), 676 glacial lakes had expanded significantly since 1984. Of these 676 lakes, 601 lakes had more than doubled in size, 10 lakes had grown between 1.5 to 2 times, and 65 lakes had grown 1.5 times.

ISRO said that 130 of the 676 lakes are situated in India, in the Indus (65), Ganga (7), and Brahmaputra (58) river basins. These lakes have expanded as glaciers are retreating at an ever faster rate due to global warming.

How are glacial lakes formed?

The movement of glaciers causes erosion and creates depressions in the surrounding topography. When they retreat, meltwater starts to accumulate in such depressions, giving birth to glacier lakes.

ISRO categorised glacial lakes into four broad categories based on how they were formed — moraine-dammed, ice-dammed, erosion-based, and ‘others’. Moraine and ice-dammed lakes are formed when water is dammed by moraine — debris such as rocks and soil left during the movement of glaciers — and ice respectively. Erosionbased lakes are formed when water is dammed by erosion-created depressions.

While glacial lakes are crucial sources of freshwater for rivers, they also pose significant risks, specifically of GLOFs, which can have devastating consequences on communities downstream.

“GLOFs occur when glacial lakes release large volumes of meltwater due to the failure of natural dams… resulting in sudden and severe flooding downstream.These dam failures can be triggered by various factors, including avalanches of ice or rock,” ISRO said.

How is satellite remotesensing technology used to monitor glacial lakes?

The monitoring of glacial lakes and their expansion in the Himalayan region is challenging due to the rugged terrain. This is where, according to ISRO, satellite remote-sensing technology “proves to be an excellent tool for… monitoring due its wide coverage and revisit capability”.

“Satellite-derived long-term change analysis provide valuable insights for understanding glacial lake dynamics, which are essential for assessing environmental impacts and developing strategies for GLOM risk management and climate change adaptation in glacial environments,” ISRO said.

Glaciologist Ashim Sattar, Assistant Professor, Indian Institute of Technology, Bhubaneswar, said:“Most of the glacial lake sites are not accessible by motorable roads. In this scenario, remote sensing tools, which are highly advanced now, can help us monitor the growth of glacial lakes and understand their dynamics”.

He also said fieldwork can be carried out at lake sites which have been identified as potentially critical. “Fieldwork is crucial to set up instrumentation for early warning systems. These can include installing motion detection cameras, water level sensors, discharge meters etc. that can capture anomalous activity in and around glacial lakes,” Sattar said.

How can the risks posed by glacial lakes be mitigated?

In 2023, a study published in the Journal of Geophysical Research examined the risks posed by Ghepan Gath lake — located at an elevation of 4,068 m in Himachal Pradesh — to Sissu in Lahaul valley, and modelled the impacts of lowering the water levels in the lake.

It found that lowering of the lake levels by 10 to 30 m significantly reduces the impacts on Sissu town, though not completely eliminating the risks posed by a GLOM event.

One way to syphon off lake water is by using long High Density Polyethylene (HDPE) pipes. In 2016, members of the Sikkim State Disaster Management Authority and Sikkim’s Department of Science and Technology and Climate Change, among others, used this method to reduce water levels in Sikkim’s South Lhonak Lake. https://indianexpress.com

IN-SPACe releases guidelines for implementing indian space policy

Space regulator IN-SPACe recently unveiled norms, guidelines and procedures for effective implementation of the Indian space policy that opened up the sector to private players to engage in a range of activities from building and launching satellites to setting up ground stations and share remote sensing data.

The 147-page document lists out space activities that need authorisation from IN-SPACe, specifies criteria for granting such authorisations and provides necessary guidelines/pre-requisites to be fulfilled by an applicant for making an authorisation application.

The norms, guidelines and procedures (NGP) will complement the government’s endeavour in providing a predictable regulatory regime, transparency and ease of doing business in the Indian space sector. www.ptinews.com

NASA, Japan advance space cooperation

NASA Administrator Bill Nelson and Japan’s Minister of Education, Culture, Sports, Science and Technology (MEXT) Masahito Moriyama have signed an agreement to advance sustainable human exploration of the Moon. Japan will design, develop, and operate a pressurized rover for crewed and uncrewed exploration on the Moon. NASA will provide the launch and delivery of the rover to the Moon as well as two opportunities for Japanese astronauts to travel to the lunar surface.

President Biden and Prime Minister Kishida also announced, “a shared goal for a Japanese national to be the first nonAmerican astronaut to land on the Moon on a future Artemis mission, assuming important benchmarks are achieved.” The pressurized lunar rover is intended to enable astronauts to travel farther and work for longer periods on the lunar surface. The signing took place April 9 at NASA Headquarters in Washington. Along with Nelson and Moriyama, JAXA (Japan Aerospace Exploration Agency) President Hiroshi Yamakawa also participated in the signing. www.nasa.gov

Muon Space and Earth Fire alliance unveil FireSat constellation

Muon Space, an end-to-end Space Systems Provider that designs, builds, and operates mission-tailored low-earth orbit (LEO) satellite constellations, in partnership with Earth Fire Alliance (EFA), has announced the FireSat Constellation. This initiative aims to transform global wildfire response and enhance climate resilience worldwide. FireSat has been developed over the last five years with the expertise and support of Google Research and leading non-governmental organizations (NGOs) including the Environmental Defense Fund (EDF), Google.org, the Gordon and Betty Moore Foundation, and the Minderoo Foundation along with guidance from over 200 members of the federal, state, and local fire community. The FireSat Constellation will provide the most comprehensive, high-fidelity data to protect Earth’s ecosystems from the escalating threat of wildfires. www.muonspace.com

ESA and Luxembourg extend space resources collaboration

ESA and the Government of the Grand Duchy of Luxembourg signed an extension of their memorandum of cooperation concerning the field of space resources for another five years, underscoring both parties’ commitment to advancing sustainable and peaceful exploration beyond Earth.

Key areas of convergence include developing the space resources sector to facilitate sustainable space exploration, while fostering the creation of new markets and business opportunities as well as using the technological innovations from this field to improve life on Earth.

The extension has been signed in the context of a visit of ESA’s Space Research and Technology Centre (ESTEC) in Noordwijk by the Minister of the Economy, SME, Energy and Tourism, Lex Delles. ESTEC is the European Space Agency’s technical center. It is ESA’s largest center where around 2,500 technicians, engineers and researchers, including Luxembourgish experts, work on space technology development and spacecraft design. meco.gouvernement.lu

First two worldview legion spacecraft performing well after launch

Maxar Intelligence has confirmed the first two WorldView Legion satellites are performing well after its recent launch on a SpaceX Falcon 9 rocket. These two satellites are part of a first block of six WorldView Legion satellites. When these six satellites join Maxar Intelligence’s constellation, the business will be able to collect imagery of the most rapidly changing areas on Earth as frequently as every 20 to 30 minutes. www.maxar.com