[A-CG06] Asian monsoon hydroclimate

[ACG06-02] MJO role on Intraseasonal variation of stable isotope of Precipitation in Indonesia Maritime Continent

*Halda aditya BELGAMAN¹, Kimpei ICHIYANAGI¹, Masahiro TANOUE², Rusmawan SUWARMAN³, Kei YOSHIMURA⁴, Shuichi MORI⁵, Naoyuki KURITA⁶ (1.GSST Kumamoto Univ., 2.School of Engineering, The University of Tokyo, 3.Bandung Institute of Technology, 4.AORI, The Univ. of Tokyo, 5.JAMSTEC, Japan, 6.Nagoya Univ.)

Keywords:asian monsoon disturbance, stable isotope, Madden Julian Oscillation, moisture transport analysis

MJO (Madden-Julian Oscillation) is one of the disturbances for Asian Monsoon in the Maritime Continent Area. Intraseasonal variability of precipitation in the Indonesia Maritime Continent (IMC) is mainly due to The Madden-Julian Oscillation (MJO), cold surge, or other synoptic scale disturbance. This study examined the relationship between MJO and stable isotope in precipitation over the IMC. Observation and simulation model data from isotope circulation model was used. From 2001 - 2009, 10 main MJO events were detected and 6 of the event occurred at Boreal Winter season (Asian Monsoon). Temporal and spatial analysis from simulated stable isotopes model reveals that isotopic variation is correlated to MJO event in different phase for different stations. Generally, δ¹⁸O in precipitation became lighter in most observation station at phase 3, 4 and 5 at western part of IMC, and phase 4, 5, and 6 at north east part of IMC. Spatial distribution of δ¹⁸O in precipitation for each MJO phase show that mainly MJO governed δ¹⁸O variability in intraseasonal timescale for IMC area. Further investigation showed clear signal of MJO in δ¹⁸O was observed at Bukit Tinggi (GAW) station only; it is confirmed with result from Isotope Circulation Model (ICM). When MJO is in active phase (enhanced) precipitation in western part of IMC, precipitable water was came from Indian Ocean and South IMC Ocean.