Indian earth observation programme towards societal benefits: GEOSS perspective

Indian Earth Observation (EO) Programme, since its inception has been applications driven and national development has been its main motivation. In order to meet the observational requirements of many societal benefit areas, a series of EO systems have been launched in both polar and geo synchronous orbits. Starting from Bhaskara, the first experimental EO satellite in 1979 to Cartosat-1 successfully launched in May 2005, a large number of sensors operating in optical and microwave spectral regions, providing data at resolutions ranging from 1 km to a meter have been built and flown. Data reception and processing facilities have been established not only in the country but also at various international ground stations. Remotely sensed data and its derived information have become an integral component of the National Natural Resources Management System (NNRMS), a unique concept evolved and established in the country. The paper discusses the evolution of IRS satellite systems, application programmes in different societal benefit areas and the road ahead. How it complements and supplements the international efforts in the context of Global Earth Observation System of Systems has also been indicated

CARTOSAT-1: The latest from the Indian Remote Sensing satellite series

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Estimation of growth stages of wheat from spectral data

Growth stages of wheat subjected to different fertilizer treatments and sown on different dates have been estimated using spectral data. Greenness profiles were generated for different wheat plots. The profile parameters have been used to calculate growth stages at various times in the growing season. The model proposed by Badhwar (1981) has been used for this purpose. Results show that the model is capable of predicting growth stages accurately. There is a high correlation (r=O.97) between the observed and the predicted growth stages of wheat grown under various treatments

Role of earth observations for sustainable development: emerging trends

Sustainable development aims at optimal use of natural resources, protection and conservation of ecological systems, and improving economic efficiency. It tries to provide food, fuel, fiber and shelter for the ever increasing world population on sustainable basis. Ecosystems like agro, coastal, forest, freshwater and grasslands, and natural disasters are some of the ideal facets for examining the magnitude of the problems and the plausible solutions that need to be generated. Decision-making for sustainable development is a complex process and involves studying trade-offs that need to be made among conflicting goals of different sectors. The present paper examines the scope for Earth Observation (EO) contributions towards the above, and tries to profile the EO capabilities vis-a-vis the systems' information needs. It further identifies the gaps, which EO needs to fulfill towards meeting either the imaging or processing needs of various applications. Considering these, in the next 6-7 years, a host of spacecraft systems carrying different sensors have been planned across the globe including India. Endeavours of NASA, ESA, India, JAXA etc. and complementary data sharing initiatives by International Charter on Space and Major Disasters and the UN agencies are expected to enlarge the scope for increased role of EO data towards the cause of sustainable development

Atmospheric correction using 1240 and 2130 nm combination of MODIS SWIR channels

It is essential to improve understanding of coastal ocean since the majority of the world's primary production occurs on continental shelves and the coastal ocean is most utilized and impacted by humans. The first step in ocean-colour data processing is the removal of atmospheric contribution from the sensor-detected radiance to enable detection of optically active oceanic constituents e.g. chlorophyll-a, suspended sediment etc. Black ocean assumption at the near infrared (NIR) wavelengths as applied to perform atmospheric correction fails for coastal turbid waters due to the presence of highly scattering sediments which cause sufficient water-leaving radiance in NIR wavelengths and lead to over-estimation of aerosol radiance for λ <700nm resulting in negative water leaving radiance for λ <500nm. The assumption of zero water-leaving radiance at the NIR wavelengths was replaced by the assumption of zero water-leaving radiance at the short wave infrared (SWIR) wavelengths over the coastal turbid waters and atmospheric correction was performed using these SWIR wavelengths. Physically realistic and positive water leaving radiances throughout the spectrum and especially for shorter wavelengths (412nm, 443nm, 490nm) were obtained over coastal turbid waters using this concept

Estimating wheat yield: an approach for estimating number of grains using cross-polarised ENVISAT-1 ASAR data

In this paper an attempt to model wheat yield is made by exploiting characteristic interaction of cross-polarised SAR with wheat crop. SAR backscatter from a crop field is affected by the density, structure, volume and the moisture content of various components of plant (viz. head, stem, leaf) alongwith soil moisture. Hence, to effectively handle the influence of each of these components of the plant on SAR backscatter, a plant parameter, termed as Interaction Factor (IF) is conceptualised by combining volume, moisture, height for each of the component and density of plant. For this purpose, detailed experiment over farmers' fields was carried out in synchrony with SAR acquisition involving in-depth measurements on volume, moisture content and height of various components of wheat plant, number of grains, plant density and soil moisture. Stepwise regression analysis revealed that IFHead significantly affects the shallow incidence angle, cross-polarised C-band SAR backscatter. IFHead is also highly correlated to the number of grains. This is attributed to the fact that parameters of the wheat head from which IFHead is calculated, namely moisture, volume and height, determine eventual number of grains. The study offers an approach for estimating wheat yield by retrieving number of grains from shallow incidence angle cross-polarised SAR data

Climate change studies using space based observation

Climate change is associated with earth radiation budget that depends upon incoming solar radiation, surface albedo and radiative forcing by greenhouse gases. Human activities are contributing to climate change by causing changes in Earth's atmosphere (greenhouse gases, aerosols) and biosphere (deforestation, urbanization, irrigation). Long term and precise measurements from calibrated global observation constellation is a vital component in climate system modelling. Space based records of biosphere, cryosphere, hydrosphere and atmosphere over more than three decades are providing important information on climate change. Space observations are an important source of climate variables due to multi scale simultaneous observation (local, regional, and global scales) capability with temporal revisit in tune with requirements of land, ocean and atmospheric processes. Essential climatic variables that can be measured from space include atmosphere (upper air temperature, water vapour, precipitation, clouds, aerosols, GHGs etc.), ocean (sea ice, sea level, SST, salinity, ocean colour etc.) and land (snow, glacier, albedo, biomass, LAI/fAPAR, soil moisture etc.). India's Earth Observation Programme addresses various aspects of land, ocean and atmospheric applications. The present and planned missions such as Resourcesat-1, Oceansat-2, RISAT, Megha-Tropiques, INSAT-3D, SARAL, Resourcesat-2, Geo-HR Imager and series of Environmental satellites (I-STAG) would help in understanding the issues related to climate changes. The paper reviews observational needs, space observation systems and studies that have been carried out at ISRO (Indian Space Research Organization) towards mapping/detecting the indicators of climate change, monitoring the agents of climate change and understanding the impact of climate change, in national perspectives. Studies to assess glacier retreat, changes in polar ice cover, timberline change and coral bleaching are being carried out towards monitoring of climate change indicators. Spatial methane inventories from paddy rice, livestock and wetlands have been prepared and seasonal pattern of CO2, and CO have been analysed. Future challenges in space observations include design and placement of adequate and accurate multi-platform observational systems to monitor all parameters related to various interaction processes and generation of long term calibrated climate data records pertaining to land ocean and atmosphere

Relation of wheat yield with parameters derived from a spectral growth profile

An attempt has been made to generate crop growth profiles using multi-date NOAA AVHRR data of wheat-growing season of 1987-88 for the districts of Punjab and Haryana states of India. A profile model proposed by Badhwar was fitted to the multi-date Normalised Difference Vegetation Index (NDVI) values obtained from geographically referenced samples in each district. A novel approach of deriving a set of physiologically meaningful profile parameters has been outlined and the relation of these parameters with district wheat yields has been studied in order to examine the potential of growth profiles for crop-yield modelling. The parameter 'area under the profile' is found to be the best estimator of yield. However, with such a parameter time available for prediction gets reduced. Combination of different profile parameters shows improvement in correlation but lacks the consistency for individual state data

Wheat crop inventory using high spectral resolution IRS-P3 MOS-B spectrometer data

Modular Optoelectronic Scanner (MOS-B) spectrometer data over parts of Northern India was evaluated for wheat crop monitoring involving (a) sub pixel wheat tractional area estimation using spectral unmixmg approach and (b) growth assessment b3 red edge shift at different phenological stages. Red shift of 10 nm was observed between crown root initiation stage to flowering stage. Wheat fraction estimates using linear spectral unmixing on Feb. 13. 1999 acquisition of MOS-B data bad high correlatiol7 {0.82) with estimates from Wide Field Sensor (WiFS) data acquired on same date by IRS-P3 platfonn. It was observed that live bands 14.5.8.12.13 MOS-B bands) are saffieient for signature separability of major land cover classes viz. wheat, urban, wasteland, and water based on purely spectral separability, criterion using Transformed Divergence (T.D.) approach. Higher number of bands saturated the T.D. values. [n contrast, performanee of sub pixel fractional area estimation using unmixing decreased drastically for eight bands (4.5.6,728.9. 12,13 MOS-B bands l chosen from optimal band selection criteria in comparison to full set of 13 bands. The relative deviation between area estimated from Wifs and MOS-B increased from 1.72 percent when all thirteen bands were used in unmixing to 26. I0 percent for the above eight bands

Space observation for climate change studies

Climate change is associated with earth radiation budget that depends upon in-comming solar radiation, surface albedo and radiative forcing by green house gases. Human activities are contributing to climate change by causing changes in Earth's atmosphere (greenhouse gases, aerosols) and biosphere (deforestation, urbanization, irrigation). Long term and precise measurements from calibrated global observation constellation is a vital component in climate system modelling. Space based records of biosphere, cryosphere, hydrosphere and atmosphere over more than three decades are providing important information on climate change. Space observations are an important source of climate variables due to multi scale simultaneous observation (local, regional, global) capability with temporal revisit in tune with requirements of land, ocean and atmospheric processes. Essential climatic variables that can be measured from space include atmosphere (upper air temperature, water vapour, precipitation, clouds, aerosols & GHGs etc.), ocean (sea ice, sea level, SST, salinity, ocean colour etc.) and land (snow, glacier, albedo, biomass, LAI/fAPAR, soil moisture etc.). India's Earth Observation Programme addresses various aspects of land, ocean and atmospheric applications. The present and planned missions such as Resourcesat-1, Oceansat-2, RISAT, Megha-Tropiques, INSAT-3D, SARAL, Resourcesat-2, Geo-HR Imager and I-STAG would help in understanding the issues related to climate changes. The paper reviews observational needs, space observation systems and studies that have been carried out at ISRO towards mapping/ detecting the indicators of climate change, monitoring the agents of climate change and understanding the impact of climate change, in national perspectives. Studies to assess glacier retreat, changes in polar ice cover, timberline change and coral bleaching are being carried out towards monitoring of climate change indicators. Spatial methane inventories from paddy rice, livestock and wetlands have been prepared and seasonal pattern of CO2, and CO have been analysed. Future challenges in space observations include design and placement of adequate and accurate multi-platform observational system to monitor all parameters related to various interaction processes and generation of long term calibrated climate data records pertaining to land ocean and atmosphere