India will commemorate its maiden National Space Day on August 23 this year to mark the successful moon landing of its Chandrayaan-3 mission (August 23, 2023). India’s space programme is now larger than ever, with several of its satellites and launch vehicles being indigenously developed and launched. Daily updates on the weather for farmers and citizens, timely alerts on extreme events such as heavy rains, cyclones and tsunamis, useful advisories on ocean state and potential fishing zones for coastal communities, and several such earth system-related services in India provided by the Ministry of Earth Sciences (MoES) are closely linked to India’s space programme and derived using satellite observations.
The father of the Indian space programme, Padma Vibhushan Vikram Sarabhai, envisioned space technology for national development and the benefit of citizens. The MoES, which is a science-for-services oriented institution of the Government of India, is the primary organisation mandated to monitor and understand the earth’s five realms: atmosphere or air; hydrosphere or oceans; lithosphere or land; cryosphere or solid earth (the Arctic, the Antarctic, and the Himalayan glaciers), and biosphere or life, and their complex interplays. The purpose of these observations (combined with data modelling and analysis) is to provide critical services related to weather and climate, ocean and coasts, and earthquakes. It is also to expand knowledge in the polar sciences and deep oceans, and to execute ambitious programmes such as scientific deep drilling. The MoES’s data and services are vital for timely and efficient disaster management in India and other Asian countries.
Ever-expanding contributions
The contribution of the Indian space mission in advancing earth system sciences and services in India is invaluable and ever expanding. The MoES (the erstwhile Department of Ocean Development) has been utilising satellite data for over six decades, and it is becoming even more intricately woven into its activities then before. Satellite data are critical for the MoES’s upcoming missions to expand atmospheric and polar sciences in India. Satellites provide the MoES and its institutes vital data for the accurate monitoring, analysis, and prediction of natural phenomena, as well as for corroborating scientific findings, which is crucial for the nation’s safety, economic stability, and environmental health. As a country, the time is right to move ahead from providing just warnings and alerts on natural disasters. The science and the services have to be centred around both mitigation and adaptation.
The MoES utilises data from several satellites (global and Indian) for its overall mission, chiefly by six of its institutes: the India Meteorological Department (IMD), the Indian National Centre for Ocean Information Services (INCOIS), the Indian Institute of Tropical Meteorology (IITM), the National Centre for Medium Range Weather Forecasting (NCMRWF), the National Centre for Coastal Research (NCCR), and the National Centre for Polar and Ocean Research (NCPOR). The data help monitor and predict weather, climate, and ocean state and issue advisories, alerts and warnings. For instance, there is dissemination of advisories on potential fishing zones and lost objects in the sea, marine pollution (including algal blooms and oil spills), coastal erosion and shoreline changes, coastal biogeochemistry, and ecosystem monitoring (such as of corals, mangroves, polar regions and Himalayan glaciers). These benefit many sectors that include agriculture, shipping, fisheries, and disaster management.
Satellites are indispensable for earth observations, providing data to monitor and understand the earth’s atmosphere, oceans, and surface. The MoES-funded GSLV-F14/INSAT-3DS, aimed at boosting India’s meteorological observations and services, was launched by the Indian Space Research Organisation (ISRO) in February 2024. In less than six months (on August 16, 2024), ISRO launched the Earth Observation Satellite (EOS-08) aboard the Small Satellite Launch Vehicle-D3 rocket, which will play a crucial role in monitoring natural disasters and environmental changes and in supporting India’s climate studies and oceanographic research. On August 6, 2024, the MoES marked the upcoming maiden National Space Day (on August 23, 2024) to celebrate the first anniversary of Chandrayaan-3’s moon-landing success. There was a day-long event at INCOIS, Hyderabad, in collaboration with the National Remote Sensing Centre, ISRO.
The ocean mission
An important vertical of India’s deep ocean mission — it aims to enhance ocean observation and climate change advisory services — will also heavily consume satellite data. As a part of this vertical, scientists at INCOIS will derive long-term projections of climate variables such as sea level rise, cyclones, storm surges, and marine ecosystems and study their impact on the coastal regions of India. Monitoring polar ice and Himalayan glaciers through satellites will also be expanded because these are vital determinants of sea level rise and global climate cycles. The earth’s observation data can also help improve the accuracy of prediction models for studying teleconnections between the polar and tropical regions and in facilitating real-time sea ice tracking for safer shipping and polar operations in the polar areas.
The MoES-ISRO collaboration can ensure that India remains at the forefront of satellite technology, enabling the country to respond effectively to natural disasters and provide beneficial earth science-related services. An Atmospheric and Space Research Facility is upcoming in Odisha, which will help further improve monsoon and thunderstorm predictions. It is a joint effort of the MoES, ISRO and the Defence Research and Development Organisation (DRDO). Discussions are progressing on indigenously developing advanced GSAT-6 satellites with transponders to enable faster two-way communication with tsunami buoys. India will soon launch the INSAT fourth-generation, RISAT-1B, and Oceansat-3A with a more significant number of and higher-resolution imagers and sensors. More wind profilers will be set up for better weather prediction, especially of severe weather events, and existing sensors will be upgraded for more valuable advisories.
The ongoing focus on indigenously developing and launching satellites will provide newer opportunities for Indian institutions, including private players, to expand a scientific understanding of earth’s processes to address the global challenges of the 21st century. The ISRO-MoES collaboration is essential in achieving the Prime Minister’s vision of ‘Viksit Bharat’ by 2047. Incorporating more advanced satellite sensors, improving resolution (both temporal and spatial) and data processing capabilities, and real-time integration of satellite data with ground-based observations can be the big game changers.
Satellites and services
A (non-exhaustive) list of the Indian satellites utilised for earth sciences services is given has been tabulated below.
Satellite: INSAT (Indian National Satellite System) series
Detail: Multipurpose geostationary satellites with advanced imaging and sounding sensors for meteorological observations
Key utilisation by the MoES: Monitoring of weather conditions in real-time, including temperature, humidity, and cloud cover: mainly utilised for predicting cyclones, monsoons, rainfall, and storm formation
Satellite: Oceansat series
Detail: Multipurpose geostationary satellites for ocean observations
Key utilisation by MoES: Monitoring of ocean state in real-time, including sea surface temperature and chlorophyll colour, to name a few
Satellite: RISAT (Radar Imaging Satellite) series
Detail: All-weather surveillance satellites for high-resolution radar images of the earth’s surface.
Key utilisation by MoES: Monitoring soil moisture and tracking floods and landslides.
Satellite: Cartosat series
Detail: Remote sensing satellites for high-resolution, panchromatic and multispectral imaging of the earth’s surface
Key utilisation by MoES: Monitoring and mapping land changes, including creating maps for inundation and shoreline changes.
Satellite: SARAL (Satellite with ARgos and ALtiKa)
Detail: A cooperative mission between ISRO and the French space agency, CNES, carrying ARgos for data collection and ALtiKa (radar altimeter) to measure sea surface height
Key utilisation by MoES: Monitoring sea level rise, ocean circulation, and wave heights, especially in predicting storm surges and tsunamis
Satellite: SCATSAT-1
Detail: Scatterometer satellite for ocean and weather research
Key utilisation by MoES: Monitoring and predicting cyclones and other extreme weather events, improving models for weather forecasting, and providing data for climate research, especially wind vector data patterns (speed and direction) and ocean currents
M. Ravichandran is Secretary to the Government of India, Ministry of Earth Sciences
