2015/2016 El Niño event and Its impact on Vietnam

Abstract

This article analyzes the development of 2015/2016 El Niño event, the variability of atmospheric circulation and anomaly of weather event across the Asia - Pacific and Viet Nam through oceanic and atmospheric indicators. The very strong 2015/2016 El Niño event with highest ONI index was +2.3^oC which was 0.2^oC below 1997/1998 El Niño, but longest remain recorded. The 2015 annual temperature was mostly warmer than normal by 1.0^oC to 1.5^oC. However, during the peak El Niño event in Jan 2016, the activity of the Asian high-pressure (AHP) was strongest development with the highest pressure of the central recorded as 1079 mb which was 44 mb higher than normal. The cold air mass from AHP brought lowest temperature recored over Northeast Asia such as Japan and Korea, etc. In Viet Nam, the lowest temperature values in the El Niño event cycle also occurred in Jan. with most of lowest temperature was below 5^oC over the North. Especially, tempareture was lower than 0^oC at Mau Son (-5^oC) and Sa Pa (-4.2^oC) etc. During 2015, there were only 2 tropical cyslones which directly affected Viet Nam which is lower than normal by 5 events. The total annual rainfall was below normal over most areas, caused severe drought in many regions. Especially serious drought occurred over the Mekong Delta and Central Highlands which supported saltwater intrusion in coastal areas. Drought and saltwater intrusion caused major damages and losses in many regions of Viet Nam.