India launching satellite to study tropical climate

September 10th, 2011 - 11:47 pm ICT by IANS  

ISRO Bangalore, Sep 10 (IANS) India will launch on Oct 12 a dedicated satellite to study climatic and atmospheric changes in the tropical regions in collaboration with the French space agency, a top space agency official said Saturday.

“All going well, we will launch the satellite - Megha-Tropiques — Oct 12 to an orbit of 870 km with an inclination of 20 degrees to the equatorial region to study the life cycle of convective systems and their role in the energy and moisture budget of the atmosphere in tropical regions,” state-run Indian Space Research Organisation (ISRO) chairman K. Radhakrishnan told reporters here.

The 1,000 kg satellite will be launched on a 230-tonne core rocket (polar satellite launch vehicle) from the space agency’s spaceport at Sriharikota in Andhra Pradesh off the Bay of the Bengal, about 80 km north-east of Chennai.

“The satellite will carry four instruments — an imaging radiometer microwave analysis and detection of rain and atmospheric structures (MADRAS), a six channel humidity sounder (SAPHIR), a four channel scanner for radiation budget measurement (SCARAB) and GPS Radio Occultation System (GPS-ROS),” Radhakrishanan said.

India will the second nation in the world to launch such a unique space mission after the Tropical Rainfall Measuring Mission (TRMM), a joint space mission between the US National Aeronautics Space Administration (NASA) and the Japan Aerospace Exploration Agency (JAXA) designed to monitor and study tropical rainfall, launched Nov 27, 1997.

“The TRMM spacecraft in a similar low orbit is positioned at an inclination of 35 degrees to the equatorial region, while Megha-Tropiques will orbit at a low inclination of 10-20 degrees to north-south of the equator to enhance observational capability of the rapidly developing tropical systems and will enable monitoring of weather and climate over the entire tropical world,” Radhakrishanan told IANS later.

Being a joint project between India and France, ISRO will bear the launch cost of Rs.90 crore. For the cost of the satellite payload, including the instruments, ISRO has spent Rs.80 crore and the state-run French space agency — Centre National d’√Čtudes Spatiales (CNES) Rs.300 crore (47 million euros).

Of the four instruments (sensors) in the satellite, MADRAS has been built jointly by ISRO and CNES, while other three (SAPHIR, SCARAB & GPS-ROS) have been built by the latter.

“About 30 minutes after lift-off, the space agency’s telemetry, tracking and command network (ISTRAC) will take control of the satellite and the three instruments onboard will be switched on within in the following three weeks,” Radhakrishnan said.

The scientific data will be collected by the space agency’s deep space network at Bylalu, about 40 km from Bangalore, and the Kourou spaceport in French Guiana on the equatorial Pacific area.

The satellite, with a five-year lifespan, will be made operational after three months of characterisation and validation by 21 principal investigators

The spacecraft will primarily cover the Indian Ocean, Africa and Brazil in South America and contribute to the Global Precipitation Measurement Mission (GPMM) the US and Japan are planning to launch jointly in 2012.

As one of the most advanced and complex tropical weather and climate monitoring satellites, Megha-Tropiques will investigate the tropical regions as they receive maximum energy from the sun than they radiate back into space.

“The excess energy received in the tropical region is utilised as a thermal engine and provides circulation in the atmosphere and oceans. This has substantial influence and is linked to hydrological cycle, which influences tropical convective systems,” ISRO’s space applications centre director R.R. Navalgund said.

The complex processes between solar radiation, water vapour, clouds, precipitation and atmospheric motion determine the life cycle of convective systems and influence Indian monsoon in the tropical region.

“The dedicated satellite will study cloud systems, radiation budget, water vapour profiles and temperature and humidity profiles in our troposphere on a more frequent basis. It will also provide reliable parameters to understand global tropical weather and climate,” Navalgund noted.

As a five frequency nine channel passive microwave radiometer, MADRAS will provide estimation of rainfall, water vapour, liquid water, ice and surface wind speed in these systems.

The second sensor (SCARAB) is a cross track scanning radiometer providing data on the radiative budget of tropical convective systems, while the third, Sondeur Atmospherique du Profil d’humidite Intertropicale par Radiometrie (SAPHIR) is a multi-channel cross track millimeter wave humidity sounder for atmospheric profiling in the inter-tropical region.

As the fourth payload in the spacecraft, GPS-ROS will measure water vapour and temperature profiles in the tropics.

“In addition, the mission will carry three nano-satellites - a 3kg remote sensing satellite ‘Jugnu’ of the Indian Institute of Technology (IIT-Kanpur), a 10kg SRMSAT of the SRM University in Chennai, and a 30kg VesselSat of Luxumbourg,” Radhakrishnan pointed out.

The VesselSat carries an automatic identification of ships instrument (AIS) of Luxspace, a Luxumbourg-based company.

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