Warm Pool Fluctuations Due to The Effect of ENSO in West Pacific and Indonesia Seas (Study Case El-Nino 2015)

Abstract

Warm pool in Pacific Ocean is a good subject to study ocean dynamics and atmospheric conditions in the Pacific Ocean. Warm pool is defined as a water mass with temperatures above 29°C located in the Pacific Ocean. Warm pool is very influenced by the dynamics of both ocean and atmosphere conditions, which is primarily an El-Nino Southern Oscillation (ENSO) phenomenon. The last ENSO phenomenon occurred in 2015, the very strong El - Nino, which is a fairly severe event comparable to El - Nino 1998. Thus, this research was conducted with the aim of identifying the characteristics of warm pool in the western Pacific ocean and Indonesian waters along with their changes due to the El-Nino phenomenon in 2015. To be able to understand the warm pool characteristic of warm pool, this research use 3 dimensional hydrodynamic model from Regional Ocean Model System (ROMS). Then, the model results are verified using 2 buoy data of TAO / TRITON and obtained each RMSE 0.368 and 0.654 and correlation 0.843 and 0.81. From this research, we can conclude that there is a shringkage extents of warm pool surface profile when the El-Nino event occurs in 2015 compared to normal condition. When normal conditions, warm pool is located from the equator up to 10°LU and disappears when the peak El-Nino occurs the warm pool only on the equatorial area. In addition, from vertical profiles warm pool can reach until 50m depth when the normal condition then disapperars when El-Nino peak occurs.