Indian Space Research Organisation

About: Indian Space Research Organisation is a government organization based out in Bengaluru, India. It is known for research contribution in the topics: Antenna (radio) & Monsoon. The organization has 5400 authors who have published 5731 publications receiving 62375 citations. The organization is also known as: ISRO & Indian Space Research Organization.

Character and Spatial Distribution of OH/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1

Abstract: The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M 3 ) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M 3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration.

Radiative effects of natural aerosols: A review

Abstract: In recent years, there has been a substantial increase in interest in the influence of anthropogenic aerosols on climate through both direct and indirect effects Several extensive investigations and coordinated field campaigns have been carried out to assess the impact of anthropogenic aerosols on climate However, there are far fewer studies on natural aerosols than on anthropogenic aerosols, despite their importance Natural aerosols are particularly important because they provide a kind of base level to aerosol impact, and there is no effective control on them, unlike their anthropogenic counterparts Besides, on a global scale the abundance of natural aerosols is several times greater than that of the major anthropogenic aerosols (sulphate, soot and organics) The major natural aerosol components are sea salt, soil dust, natural sulphates, volcanic aerosols, and those generated by natural forest fires As with anthropogenic aerosols, the abundance of natural aerosols such as soil dust is also increasing, due to processes such as deforestation, which exposes more land areas which may then interact directly with the atmosphere, and due to other human activities Since a major fraction of the natural aerosol (sea salt and natural sulphate) is of the non-absorbing type (and hygroscopic), it partly offsets the warming due to greenhouse gases as well as that due to absorbing aerosols (eg, soot) The mineral dust transported over land and ocean causes surface cooling (due to scattering and absorption) simultaneously with lower atmospheric heating (due to absorption); this could in turn intensify a low-level inversion and increase atmospheric stability and reduce convection To accurately predict the impact of dust aerosols on climate, the spatial and temporal distribution of dust is essential The regional characteristics of dust source function are poorly understood due to the lack of an adequate database The reduction of solar radiation at the surface would lead to a reduction in the sensible heat flux and all these will lead to perturbations in the regional and global climate Enhanced concentration of sea salt aerosols at high wind speed would lead to more condensation nuclei, increase in the cloud droplet concentration and hence cloud albedo Even though direct radiative impacts due to sea salt and natural sulphate are small compared to those due to anthropogenic counterparts, their indirect effects (and the uncertainties) are much larger There is a considerable uncertainty in sea salt aerosol radiative forcing due to an inadequate database over oceans The presence of natural aerosols may influence the radiative impact of anthropogenic aerosols, and it is difficult to separate the natural and anthropogenic aerosol contributions to radiative forcing when they are in a mixed state Hence it is necessary to document the radiative effects of natural aerosols, especially in the tropics where the natural sources are strong This is the subject matter of this review

Observers for linear systems with unknown inputs

Abstract: This paper presents a constructive solution to the problem of designing a reduced-order Luenberger observer for linear systems subject to arbitrary unknown inputs.

Groundwater management and development by integrated remote sensing and geographic information systems: prospects and constraints

Abstract: Groundwater is one of the most valuable natural resources, which supports human health, economic development and ecological diversity. Overexploitation and unabated pollution of this vital resource is threatening our ecosystems and even the life of future generations. With the advent of powerful personal computers and the advances in space technology, efficient techniques for land and water management have evolved of which RS (remote sensing) and GIS (geographic information system) are of great significance. These techniques have fundamentally changed our thoughts and ways to manage natural resources in general and water resources in particular. The main intent of the present paper is to highlight RS and GIS technologies and to present a comprehensive review on their applications to groundwater hydrology. A detailed survey of literature revealed six major areas of RS and GIS applications in groundwater hydrology: (i) exploration and assessment of groundwater resources, (ii) selection of artificial recharge sites, (iii) GIS-based subsurface flow and pollution modeling, (iv) groundwater-pollution hazard assessment and protection planning, (v) estimation of natural recharge distribution, and (vi) hydrogeologic data analysis and process monitoring. Although the use of these techniques in groundwater studies has rapidly increased since early nineties, the success rate is very limited and most applications are still in their infancy. Based on this review, salient areas in need of further research and development are discussed, together with the constraints for RS and GIS applications in developing nations. More and more RS- and GIS-based groundwater studies are recommended to be carried out in conjunction with field investigations to effectively exploit the expanding potential of RS and GIS technologies, which will perfect and standardize current applications as well as evolve new approaches and applications. It is concluded that both the RS and GIS technologies have great potential to revolutionize the monitoring and management of vital groundwater resources in the future, though some challenges are daunting before hydrogeologists/hydrologists.

Mapping global cropland and field size

Abstract: A new 1 km global IIASA-IFPRI cropland percentage map for the baseline year 2005 has been developed which integrates a number of individual cropland maps at global to regional to national scales. The individual map products include existing global land cover maps such as GlobCover 2005 and MODIS v.5, regional maps such as AFRICOVER and national maps from mapping agencies and other organizations. The different products are ranked at the national level using crowdsourced data from Geo-Wiki to create a map that reflects the likelihood of cropland. Calibration with national and subnational crop statistics was then undertaken to distribute the cropland within each country and subnational unit. The new IIASA-IFPRI cropland product has been validated using very high-resolution satellite imagery via Geo-Wiki and has an overall accuracy of 82.4%. It has also been compared with the EarthStat cropland product and shows a lower root mean square error on an independent data set collected from Geo-Wiki. The first ever global field size map was produced at the same resolution as the IIASA-IFPRI cropland map based on interpolation of field size data collected via a Geo-Wiki crowdsourcing campaign. A validation exercise of the global field size map revealed satisfactory agreement with control data, particularly given the relatively modest size of the field size data set used to create the map. Both are critical inputs to global agricultural monitoring in the frame of GEOGLAM and will serve the global land modelling and integrated assessment community, in particular for improving land use models that require baseline cropland information. These products are freely available for downloading from the http://cropland.geo-wiki.org website.