Possible impact of El Niño and La Niña on water mass circulation in Ambon Bay

Abstract

El Niño and La Niña are disruptions to the ocean-atmosphere system in the equatorial Pacific area, with significant impacts on the climate and weather throughout the world. This paper discusses the possible impact of El Niño and La Niña to the water mass circulation in Ambon bay which is directly adjacent to the Banda Sea. We used observed vertical temperature variability data in June, July, September, and October in the year of 2008 (neutral year) and 2009 (El Niño year), and July and October 2010 (La Niña year). All data have been taken with CTD instrument in 7 stations which are aligned in one straight line from inner to Ambon Outer Bay (AOB). The result shows that the water mass circulation in Ambon Bay may be affected by El Niño and La Niña. El Niño phase makes the thermocline layer from the Banda Sea to become shallower than usual and thus makes the circulation in Ambon Bay more rigorous. This is because the water mass with higher density can enter into the deep Ambon Inner Bay (AIB) through the narrow sill which separates the Ambon Bay inner from outer parts. La Niña, on the other hand, weakens the water circulation because the thermocline layer becomes deeper than usual.