Current Science

R. M. Gairola ¹, Satya Prakash ², M. T. Bushair ¹, P. K. Pal ¹

Affiliations
1 Atmospheric and Oceanic Sciences Group, Earth, Ocean, Atmosphere, Planetary Sciences and Applications Area, Space Applications Centre, Indian Space Research Organisation, Ahmedabad 380 015, IN
2 National Centre for Medium Range Weather Forecasting, Earth System Science Organization, Ministry of Earth Sciences, Noida 201 309, IN

Abstract

Rainfall, an integral component of the global water and energy cycle, is one of the critical weather elements. Reliable information of rainfall over India is crucial for food security and sustainable economic growth. The first Indian dedicated meteorological geostationary satellite Kalpana-1 was launched by the Indian Space Research Organisation in late 2002 to study the synoptic weather systems, monsoons and extreme weather events. Various geophysical parameters derived from this satellite measurements are operational and used for a wide range of applications. Two rainfall products, based on distinct algorithms, from this satellite are also available to users. These two algorithms after certain refinements are also applied to the recently launched INSAT-3D satellite measurements to estimate rainfall. In this article, the algorithms used for the development of these Kalpana-1-based rainfall products are summarized. The assessment of these rainfall products against standard multisatellite datasets and in situ observations are also outlined. Both the rainfall products are comparable with independent multisatellite datasets and have reasonable agreement with ground-based observations over the Indian land and oceanic regions. Limitations of these rainfall products are also presented; and future scope for further refinement of these products in perspective of upcoming Indian geostationary satellite missions is proposed.

Keywords

Indian Monsoon, Kalpana-1 Satellite, Rainfall Estimation, Thermal Infrared.

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Satya Prakash ¹, R. M. Gairola ², F. Papa ³

Affiliations
1 National Centre for Medium Range Weather Forecasting,Earth System Science Organization, Ministry of Earth Sciences, Noida 201 309, IN
2 Atmospheric and Oceanic Sciences Group, Space Applications Centre, Indian Space Research Organisation, Ahmedabad 380 015, IN
3 Institut de Recherche pour le Developpement (IRD), LEGOS, Toulouse 31400, FR

Abstract

Terrestrial water storage (TWS) plays a key role in the global water cycle and is highly influenced by climate variability and human activities. In this study, monthly TWS, rainfall and Ganga-Brahmaputra river discharge (GBRD) are analysed over India for the period of 2003-12 using remote sensing satellite data. The spatial pattern of mean TWS shows a decrease over a large and populous region of Northern India comprising the foothills of the Himalayas, the Indo-Gangetic Plains and North East India. Over this region, the mean monthly TWS exhibits a pronounced seasonal cycle and a large interannual variability, highly correlated with rainfall and GBRD variations (r > 0.8) with a lag time of 2 months and 1 month respectively. The time series of monthly TWS shows a consistent and statistically significant decrease of about 1 cm year^-1 over Northern India, which is not associated with changes in rainfall and GBRD. This recent change in TWS suggests a possible impact of rapid industrialization, urbanization and increase in population on land water resources. Our analysis highlights the potential of the Earth-observation satellite data for hydrological applications.

Keywords

Earth-Observation Satellites, Rainfall, River Discharge, Terrestrial Water Storage.

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