Persistent volcanic signature observed around Barren Island, Andaman Sea, India

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ORIGINAL PAPER

Persistent volcanic signature observed around Barren Island, Andaman Sea, India C. M. Laluraj Æ K. K. Balachandran Æ P. Sabu Æ S. U. Panampunnayil

Received: 26 April 2006 / Accepted: 27 August 2006 / Published online: 28 October 2006  Springer Science+Business Media B.V. 2006

Abstract This study delineates the formation of a warm pool (>34C) of air to the west (downwind) of the active volcano of the Barren Island during October– November 2005. Barren Island is located in the Sumatra–Andaman region, about 135 km east of Port Blair, and lies within the Burma microplate, the southern tip of which experienced a submarine earthquake (Mw 9.3) causing a tsunami in December 2004. Barren Island is the only volcano, which has shown sustained eruptive activity since shortly after the Great Sumatran Earthquake of December 2004. Our observations require further corroboration to relate how submarine earthquakes activate volcanoes and how far these thermal emissions influence climate changes. Because it links global warming and climate changes to the frequent emissions from a volcano activated by submarine earthquakes, this case study is of special interest to the earth-ocean-atmosphere sciences community. Keywords Andaman Sea Æ Barren Island Æ Volcano Æ Warm air pool Æ Global warming Introduction The causes of the global surface air temperature warming in the previous century remain a topic of C. M. Laluraj Æ K. K. Balachandran Æ P. Sabu Æ S. U. Panampunnayil National Institute of Oceanography, Regional Centre, 1913, Kochi 682018, India Present Address: C. M. Laluraj (&) National Centre for Antarctic and Ocean Research, Headland Sada, Goa, India e-mail: [email protected]

debate (Shiogama et al. 2006). Although it is known that increase in greenhouse gases and solar irradiance changes are responsible for the rise in the surface air temperature (Stott et al. 2003), recent studies suggest that natural forcing such as volcanic activity, along with solar irradiance changes may be the most important factors influencing global warming (Hegerl et al. 2003; K-I Model Developers 2004; Nozawa et al. 2005). Understanding the forcing functions of the past climate change is much needed to improve the global circulation model and to predict future climate changes precisely. In this study, we present observational evidence of a warm air pool supporting the relative importance of volcanic emissions on surface air heating in the Bay of Bengal, a region of tropical cyclones (Pankajakshan et al. 2002; Shenoi et al. 2002). On 24 December 2004, this region experienced a devastating tsunami caused by a submarine earthquake, the deadliest disasters in modern history (Javed and Murty 2005; Waltham 2005; Bandopadhyay et al. 2006; http:// www.volcano.si.edu/reports/usgs/index). The very fact that a warm air pool was observed in the Andaman Sea where the Stratovolcano (Barren Island) erupted soon after the Great Sumatran Earthquake, makes this study important to models linking climate and solid Earth tectonic and magmatic activity.

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