Impact of El Niño Southern Oscillation and Indian Ocean Dipole Index on growing seasonal characteristics: A case study in Batalagoda, Sri Lanka
- June 30, 2021
- Posted by: rsispostadmin
- Categories: Agriculture, IJRIAS
International Journal of Research and Innovation in Applied Science (IJRIAS) | Volume VI, Issue V, May 2021|ISSN 2454-6194
Ampitiyawatta, A.D. * & Wimalasiri G.E.M.
Department of Export Agriculture, Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka
Abstract
Ocean atmospheric phenomenon such as El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (DMI) have an impact on global level climatic patterns and agriculture. The climate and agricultural activities of Sri Lanka, which is a tropical island in the Indian Ocean, mainly depends on the amount and the distribution of rainfall. The objective of this study was to assess the impact of ENSO and DMI on growing seasonal characteristics of Batalagoda, Sri Lanka. The growing seasonal characteristics such as the onset, retreat, length of the season, seasonal rainfall and rainy days were initially assessed using Instat Statistical Programme. Pearson correlation analysis was then performed to check their relationship with oceanic indices. The Multivariate ENSO Index and DMI did not show a significant correlation (p > 0.05) between onset, retreat and length of the season. However, the retreat of the season showed a significant (p < 0.05) relationship with Southern Oscillation Index (SOI). Both SOI and MEI showed significant (p < 0.05) correlation with the growing seasonal rainfall. Due to some signals of the impact of oceanic indices on the growing seasonal characteristics of Batalagoda, further studies are needed to be carried out throughout the county using the similar approach.
Key words: ENSO, MEI, SOI, Yala, Maha
I.INTRODUCTION
Agriculture is one of the main income sources of Sri Lanka which contributes more than 7% to the national economy. Food production in many part of the world highly dependent on climate inputs such as growing season temperatures and rainfall (Abbas and Mayo, 2021). Being a tropical country, marked seasonal temperature variation cannot be observed, hence rainfall pattern plays a major role to determine climatic characteristics in Sri Lanka (Kurukulasuriya and Ajwad, 2007; Esham and Garforth, 2013). Three types of rainfalls namely, monsoonal, conventional and cyclonic are identified in Sri Lanka, in which monsoons are the dominant. Four monsoon seasons can be observed in Sri Lanka as; South West monsoon (SWM) from June to September, North East Monsoon (NEM) from December to February, First Inter-Monsoon (FIM) from March to
