“The satellite, SARAL, will be launched next year. It will have instruments to measure ocean surface topography accurately,” said Shailesh Nayak, secretary to the Union Ministry of Earth Sciences.
SARAL is an Indo-French joint payload, which will complement ocean data collected by European Space Agency’s ENVISAT. It will fly in the same orbit.
“One of the primary tasks of SARAL would be keeping an eye on the mean sea level,” Marc Pircher, director of the Toulouse Space Centre under the French space agency CNES, said at the 97th session of the Indian Science Congress here.
Nayak said between 2004 and 2008, the mean sea level of the Indian Ocean has risen cumulatively by 9 mm, almost 2.5 mm every year. This is at par with the observed global trend. Between 1961 and 2003, the mean sea level went up by 1.8 mm globally every year. The rise was accelerated in the recent past with recording of 3.1 mm sea level rise between 1993 and 2003.
Studies conducted by the Indian Centre for Ocean Information Services (INCOIS), Hyderabad, shows the same trend in the Indian Ocean as well. The INCOIS scientists sourced their data from argo floats in the high seas (small buoys fitted with instruments to measure various ocean parameters) and two NASA satellites, GRACE and Jason-2.
Many spots along the Indian coastal lines and islands are vulnerable to the sea level rise. “We have witnessed some erosion in Lakshadweep,” Nayak said.
The sea level rise is the maximum at Diamond Harbour, close to the mouth of the Hooghly river in West Bengal. The sea level climbed up by 5.74 mm every year since the last 55 years. Other vulnerable spots include Visakhapatnam, Kochi and Mumbai.
Incidentally, in the Copenhagen climate summit, island nations like the Maldives and Vanuatu demanded fixing the maximum permissible limit for global temperature rise at 1.5 degrees Celsius instead of 2 degrees.
They will be under water with 2 degrees Celsius rise. The UN climate convention agreed to review their plea in 2015 after receiving the fifth assessment report from the Inter-governmental Panel on Climate Change.
India is also expanding its network of tidal gauges with 21 additional automated gauges being added to the existing survey of India network.
DH News Service