Satellite to study climate change

Few issues have taken the global centre stage as did climate change recently, and images of melting polar ice caps and rising sea levels are now all too ubiquitous to ignore. But how much do we really know about global warming? What is the quantity of greenhouse gases — carbon dioxide, carbon monoxide and methane — in our atmosphere? How are they distributed around the world?Some answers might be brought back by I-STAG, a satellite to be launched by the Indian Space Research Organisation (ISRO) in 2012, in a unique collaborative initiative with science institutes."I-STAG, (Indian Satellite for Aerosol and Gases) is a small satellite, weighing no more than 150 kg and will most likely go as a co-passenger with one of the major launches scheduled for 2012," R. Sridharan, Programme director, Space Science Office, ISRO, told The Hindu. It will be placed in a low Earth orbit at 600 km. In its two-year life span, I-STAG will collect data on the quantity and distribution of carbon monoxide, carbon dioxide, aerosols (suspended particulate matter), ozone, water vapour and the oxides of nitrogen and sulphur so that an estimate can be made on their impact on climate. "The satellite will have a special focus on the tropics and will monitor the spatial and temporal variation in the amount of these gases to assess their long-term effect on the climate and ecosystem," said Prof. Sridharan. The experiments would also attempt to estimate the impact of biomass burning and forest fires on climate. I-STAG will be developed jointly by the Indian Institute of Science, the Space Physics Laboratory in Thiruvananthapuram, the Physical Research Laboratory in Ahmedabad, and the National Atmospheric Research Laboratory in Tirupati.

"ISRO will put in the seed money of about Rs. 10 crore, and scientists will, through simulations, demonstrate the concepts and also work out the methods for analysing the data," Prof. Sridharan said.

The three experiments on I-STAG would measure and trace the distribution of greenhouse gases through an infrared spectrometer, and a multiwave radiometer would monitor the distribution and polarisation properties of aerosols. I-STAG is part of the space organisation's "small satellites programme" for scientific experiments, said ISRO Chairman G. Madhavan Nair. "The first of the series of small satellite was the Indian Mini Satellite, which flew with CARTOSAT-2A. We are scheduled to launch three more small satellites in the next four years, including I-STAG. These are SENSE, to study the near-space environment; Aditya, to study the solar corona; and YOUTHSAT to measure solar radiation," he said. Prof. Sridharan said the science institutes were now preparing the project report for I-STAG in consultation with the satellite group at the ISRO Satellite Centre.

The Hindu, June 25, 2008

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