Space as an unlimited boundless expanse, holds the observer’s mind in awe and immersion as it sows seeds of holistic thoughts and insights from the elements around us. A platform capturing images from a vantage point provides the human mind, the panorama, that innately inspires a connect between entities and elements inherent to the ecosystem. The technology of capturing mother earth from lofty heights in space, be it lower earth, polar and geostationary orbits at about 500, 800 and 36000 km, respectively, or from flying aeroplanes, has been providing us extremely diverse data on landscapes since the start of space age. This process is known as remote sensing or Earth Observation, where various windows of the electromagnetic spectrum are used to image the surface of the earth from space-borne satellites.
India has established itself as a significant player in the global space community, particularly in developing the Earth Observation (EO) System. The Indian Earth Observation (EO) programme of the Indian Space Research Organisation (ISRO) aims to monitor and manage natural resources, support disaster management, and contribute to scientific research about our own planet.
THE EO JOURNEY
Indian Earth Observation programme, founded on the basis of self-reliance and to cater to the needs of the nation, has come a long way on all fronts of satellite building, sensor development, data reception and data handling, applications and capacity building. India’s journey for space-based Earth Observation began with the launch of its first satellite, Aryabhata, in 1975. However, the dedicated Earth Observation programme took shape with the launch of the Bhaskara series in 1979 and 1981. These early missions laid the foundation for the development of advanced EO satellites that followed. IRS-1A launched in 1988 was the first operational remote sensing satellite, providing data for agriculture, forestry, and land-use mapping. IRS-1A was followed by IRS-1B and IRS-1C/1D satellite systems to provide continuity of remote sensing data.
Starting with the modest spatial resolution of 36m with IRS-1A/1B, today ISRO’s CARTOSAT series of satellites are providing very high-resolution images at ~28 cm resolution (Carto-3), demonstrating the coherence, pursuit and vision at ISRO to strengthen the Indian scientific and technological paradigm at a newer level. Microwave radar imaging sensors such as RISAT-2, 2B, 2BR1, EOS4 (RISAT-1A) which provided valuable observation in C band regime, will be followed soon by NISAR (NASA ISRO Synthetic Aperture Radar). NISAR is a dual band (S & L) sensor set to revolutionise land cover observation completely. Ocean monitoring sensors onboard OCEANSAT-3 satellite have brought rapid strides in vast assessment of global ocean resources, along with Scatterometer sensor which provided standalone ocean wind vector data to the global community, useful in weather and cyclone forecasting.
APPLICATIONS OF REMOTE SENSING
Applications of remote sensing data have grown from mapping of natural resources using hard copy aerial colour and InfraRed photographs in the 1970s to quantitative geophysical parameter estimation and providing solutions to real life problems by integrating inputs from satellite remote sensing, navigation systems and mobile services through satellite communication. Realising the potential of these technologies in nation building, necessary institutionalization and capacity building has been put in place by setting up the National Natural Resources Management System and State Remote Sensing Applications Centres, respectively, at Central and state government levels. Remote sensing data is being used today to understand changing land use and land cover situations, viz., crop, water, soil, forests, grasslands. National level programmes starting from the Integrated Mission for Sustainable Development (IMSD) in the 1980s till the ongoing Space Based Information Support for Decentralised Planning (SIS-DP) have enabled transformation at the grassroots level.
All Images Courtesy: ISRO
The country faced a string of droughts between 1985-87 causing massive rural distress and needed a truly scientific and sustained solution to overcome this. A mission mode programme called the Integrated Mission on Sustainable Development, covered watersheds/ study areas in 126 districts across the nation. Profiles for social, demographic, cultural and economic orientation were prepared, and PRA was conducted to help prioritisation as per people’s needs. These remote sensing and GIS-based multi-thematic plans were distributed to implementing agencies for sustainable development, which altered the framework of decision making.
STUDYING GROUNDWATER
Groundwater forms the backbone of the Indian agrarian economy in non-irrigated tracts and hence, was required to be studied using state-of-the-art technology in the light of unplanned exploitation. A study sponsored by the Rajiv Gandhi Drinking Water Mission prepared groundwater prospects maps corresponding to the Survey of India toposheets in 1:50,000 scale. The maps depict prospective zones for groundwater occurrence and tentative locations for constructing recharge structures. The information provided in the groundwater prospects maps forms a suitable database for narrowing down the target zones and systematic selection of sites for drilling, after conducting follow-up ground surveys. Earliest application of remote sensing for assessing natural resources has been adapted by Forest Cover Assessment (in 1987) using Landsat Multi Spectral Scanner, which employed coarse pixels of 72.5 m at a scale of 1:1 million, (1981-83 data). Establishment of Forest Survey of India, from its earlier set up called “Pre-Investment Forest Survey of India” in fact involved dovetailing of Earth observation for mapping India’s forests. Given the criticality of India’s forests in its ecological wellbeing as well as the Carbon compliance in view of the global level emission related commitments, EO based assessment is an established procedure mapping forest every second year, which has few parallels across the world. FSI has published reports from 1987 till 2021, using Resource-Sat LISS III multi-spectral images. It also publishes Forest Fire alerts using Indian and international sensors detecting anomalies using thermal infrared images.
Left: Technology demonstrator satellite INS-2TD; Right: Earth observation satellite EOS–07
OCEAN OBSERVATION
Advisory to local fishermen on potential fishing zones using Indian and international ocean observation sensors has been an exemplary success story that resulted in clear and identifiable accomplishment of technology, bringing in sustainable growth of the fishing economy. Since last one-and-a-half decade, remote sensing derived biophysical oceanic parameters such as sea surface temperature, chlorophyll and ocean currents, etc., which in turn indirectly indicate swirls, upwelling regions, helping pinpoint zones of high primary productivity in an otherwise featureless oceanic surface. OCEANSAT series of satellites are operationally being used to provide these services. Artisanal and small mechanised fishermen can reach these locations, even with a time gap, after being given an advisory for each of the landing sites across the Indian coast. It has led to reducing the searching time, which in turn results in the saving of valuable fuel, oil and also human effort.
DIRECT IMPACT ON RURAL SECTOR
Support to the world’s largest rural employment programme, MGNREGA employing Geospatial Technology through the Bhuvan Web portal integrating temporal satellite data, ground inventory of assets created through a customised mobile app, stands out as another critical application directly impacting the rural sector. Buoyed by the success of applying high-resolution remote sensing for watershed development under the Integrated Watershed Management Programme, now WDC-PMKSY (Watershed Development Component – Pradhan Mantri Krishi Sinchayee Yojana), the Ministry of Rural Development in 2016 collaborated with ISRO to establish this initiative. All existing assets across India were geotagged under GeoMGNREGA initiative, by field workers to a volume of about 5-crore plus locations till date. Currently, every asset created in each village is monitored for its creation through Bhuvan GeoMGNREGA. Apart from this, GeoMGNREGA has adopted Yuktadhara, a web-based GIS-oriented planning tool for planning all future MGNREGA activities that are centred around natural resource management. The high degree of transparency and accountability achieved by this system reduced malpractices by a scale. The significance of this contribution is exemplified by its ubiquitous use and request for emulation in other nations for its value.
EO IN GOVERNANCE
The Mahalanobis National Crop Forecast Centre (MNCFC) was established by the Ministry of Agriculture & Farmers Welfare in New Delhi in April 2012 for the transfer of technology for crop acreage and estimation towards upscaling and operationalisation, which marked a strong milestone in adaptation of EO as a core tool of governance. Remote sensing-based acreage and production forecasts based on weather parameters and spectral indices were conceptualized by ISRO in the early eighties. These remote sensing-based acreage estimates were made available about one month before the harvest of the crop to enable strategic decision-making. The scope of this project was further enhanced with the FASAL (Forecasting Agricultural Output using Space, Agro-meteorology and Land-based Observations) programme. Under FASAL, the methodology was developed for multiple in-season forecasts of nine field crops at a national scale. Besides field crops, national-level assessment of horticultural crops is also being carried out as part of the CHAMAN (Coordinated Programme on Horticulture Assessment and Management using Geoinformatics) programme. The current focus covers mapping the progression of crop growth, as illustrated, using optical as well as microwave images, which give high temporal resolution monitoring ability for the entire nation.
Crop insurance has become an indispensable risk management tool in the agriculture sector, especially in agrarian monsoon-dependent countries like India. NRSC (ISRO) in close coordination with the Ministry of Agriculture, state departments of agriculture and insurance industry has developed technology interventions under the Pradhan Mantri Fasal Bima Yojana (PMFBY). Successful interventions have resulted in improving crop risk assessment systems, moderating the exaggerated crop loss assessments and eventually reducing the premium rates, benefitting farmers and other stakeholders of crop insurance. End-of-the-crop season risks like hailstorms, floods, and cyclones have been accounted for, in the crop performance, which transforms the way farmers can brace the farm exigencies.
PLANNING USE OF WATER RESOURCES
Patterns of global warming and skewed water demand in time and space put Indian water resources to severe stress. To address judicious planning of water resources through an information system, the Ministry of Jal Shakti (MoJS), under the National Hydrology Project, launched the first version of India Water Resources Information System (India-WRIS) in July 2019. It defines the highest integration of thematic content at various scales by drawing data from many central and state agencies like CWC, CGWB, IMD, NRSC and state institutions as well as setting monitoring and model-based assessment framework, adding value to the life of rural inhabitants. Farmer Welfare Associations can plan crops and cropping patterns based on the rainfall, water availability in storages and ground water aquifers.
REMOTE SENSING FOR REDUCING DISASTER RISKS
Disaster Risk Reduction forms the central core of adaptability to changing climate. Floods, forest fires, landslides, earthquakes and tsunamis pose heavy dangers at various temporal frequencies that need to be observed and analysed for better risk reduction. NRSC carries out various activities of disaster management support, under ISRO’s Disaster Management Support Programme (DMSP), using the information derived from satellite remote sensing and other sources such as IMD and CWC. These geospatial inputs are disseminated to the nationwide stakeholders, such as MHA, NDMA, SDMAs, NDRF, and State Remote Sensing Centres across the country. Thirteen states in the country witnessed major floods in 2022, and 254 flood maps and value-added products were prepared and disseminated. Apart from floods, fires occurring in forests pose a significant threat to rural livelihoods due to damage to life and property and land degradation. Van Agni portal of Forest Survey of India, MoEnFCC, is supported suitably for daily detection and dissemination of forest fire alerts using open-source images collected and analysed eight times a day. Landslides pose the highest risk to life in hilly terrain and can disrupt the economy for long. Multisource data including high-resolution 3D enabled satellite data has been employed to generate likely locations of landslides as well as mapping fresh slides in complex terrains.
National Database for Emergency Management (NDEM) implemented in 2019 emphasizes the organisation of a comprehensive uniform, structured, seamless, multiscale geospatial database for the entire country using spatial integration procedures, generation of web map services for situational assessment, and development of decision support tools. Portal hosts the services related to hydrological, geological, and meteorological services and weather forecasts and disaster specific products, etc., obtained from various authorized agencies.
A rich legacy of applying remote sensing for diverse situations demanding a holistic solution across India has demonstrated the strength of the Indian Space Programme beyond doubt. Renewed focus on involving it further in each governance domain, makes it a new horizontal, cutting across verticals of sectoral focus. Its ability to bring interdisciplinary information into the Geographic Information System can help the rural sector to innovate fast, in terms of managing farm productivity better and helping the ecological restoration convincingly. Hence, it has a great role in strengthening homegrown solutions of resource management by demonstrating a contextualisation of each, in a fast-changing world strained by climate change as well as relentless exploitation. This would pave the way for state-of-the-art technology to nurture India’s ambitions of sustainable growth as India embarks into a new space era with higher emphasis on private sector involvement and with upcoming new EO missions of ISRO.
*The writer is Director, National Remote Sensing Centre, Hyderabad.
