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Abstract. Water-soluble inorganic components in rain deposited at the Maldives Climate Observatory Hanimaadhoo (MCOH) were examined to determine seasonality and possible source regions. The study, which is part of the Atmospheric Brown Cloud (ABC) project, covers the period

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North Eastern Region (NER) of India comprising of eight states considered to be most unique and one of the most challenging regions to govern due to its unique physiographic condition, rich biodiversity, disaster prone and diverse socio-economic characteristics. Operational Remote Sensing services increased manifolds in the region with the establishment of North Eastern Space Applications Centre (NESAC) in the year 2000. Since inception, NESAC has been providing remote sensing services in generating inventory, planning and developmental activities, and management of natural resources, disasters and dissemination of information and services through geo-web services for NER. The operational remote sensing services provided by NESAC can be broadly divided into three categories viz. natural resource planning and developmental services, disaster risk reduction and early warning services and information dissemination through geo-portal services.As a apart of natural resources planning and developmental services NESAC supports the state forest departments in preparing the forest working plans by providing geospatial inputs covering entire NER, identifying the suitable culturable wastelands for cultivation of silkworm food plants, mapping of natural resources such as land use/land cover, wastelands, land degradation etc. on temporal basis.In the area of disaster risk reduction, NESAC has initiated operational services for early warning and post disaster assessment inputs for flood early warning system (FLEWS) using satellite remote sensing, numerical weather prediction, hydrological modeling etc.; forest fire alert system with actionable attribute information; Japanese Encephalitis Early Warning System (JEWS) based on mosquito vector abundance, pig population and historical disease intensity and agriculture drought monitoring for the region.The large volumes of geo-spatial databases generated as part of operational services are made available to the administrators and local government bodies for better management, preparing prospective planning, and sustainable use of available resources. The knowledge dissemination is being done through online web portals wherever the internet access is available and as well as offline space based information kiosks, where the internet access is not available or having limited bandwidth availability. This paper presents a systematic and comprehensive study on the remote sensing services operational in NER of India for natural resources management, disaster risk reduction and dissemination of information and services, in addition to outlining future areas and direction of space applications for the region.

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Water soluble inorganic components in rain deposited at the Maldives Climate Observatory Hanimaadhoo (MCOH) were examined to determine seasonality and possible source regions. The study, which is part of the international Atmospheric Brown Cloud (ABC) project, covers the period June 2005 to December 2007. Air mass trajectories were used to separate the data into situations with transport of air from the Asian continent during winter (December–April) and those with southerly flow from the Indian Ocean during the monsoon season (June–September). The concentrations of nss-SO₄^2−, NH₄⁺, NO₃^− and H₊ were more than a factor of 4 higher in winter than during the monsoon season. This shows a pronounced influence of continental pollutants during winter. The average rainwater pH was significantly lower in winter (4.7) than during the monsoon (6.0). The lower pH in winter is probably due to a more rapid decrease in the alkaline components than in the acidifying components as air is transported southwards over the Indian Ocean. The moderately high loadings of nss-SO₄^2− during the monsoon season, supported by our measurements of Methane sulphonate (MSA), indicate that Dimethyl sulphide (DMS) is likely to contribute substantially to the nss-SO₄^2− concentration during this season. The origin of the high concentration of nss-Ca₂₊ during the monsoon season – a factor of 4 to 7 higher than during the winter situations with trajectories from the continent – is unclear. We discuss various possibilities including long-range transport from the African or Australian continents, calcareous plankton debris and exopolymer gels emitted from the ocean surface. The occurrence of NO₃^− and NH₄⁺ during the monsoon season suggests emissions from the ocean surface. Part of the NO₃^− could also be associated with lightning over the ocean. Despite the fact that the concentrations of nss-SO₄^2−, NO₃^−, and NH₄⁺ were highest during the winter season their wet deposition was at least as high during the monsoon season reflecting the larger amount of rainfall in this season. The annual wet deposition of these components was comparable to that observed in the eastern US and in India but substantially higher than what has been observed on Amsterdam Island in the Southern Indian Ocean

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