Teleconnection of equatorial convection between Boreal Winter Monsoon with MJO and the interaction of Indo-Western Pacific Ocean over Maritime Continent

Mr. Khafid Rizki Rizki Pratama, Indonesian Agency for Meteorology, Climatology and Geophysics BMKG, Jakarta, Indonesia, Nelly Florida Riama, Indonesian Agency for Meteorology, Climatology and Geophysics, Education and Training, Jakarta, Indonesia and Ejha Larasati Siadari, Indonesian Agency for Meteorology, Climatology and Geophysics, Center for Marine Meteorology, Jakarta, Indonesia
Abstract:
The relationship between the Asian Boreal Winter Monson (ABWM) and MJO phases is an important problem in identifying the propagation to the surface rainfall increasing in the development of the Indo-Asian Monsoon (IAM) on the Maritime Continent. Investigations were carried out using synoptic observation data, modeling datasets and oceanic reanalysis data. Significantly, the ABWM phase is stronger for increasing of rainfall frequency in the Maritime Continent compared to the active IAM. The ABWM thermodynamic structure with MJO propagation activity reduces the frequency of the impact of the Northern Cold Surge which inhibits the growth of Borneo Vortex but influences the cumulus updraft activity. The method is carried out by classifying the convective frequencies in the Western Indonesia to ABWM propagation during active IAM and MJO and ocean-atmosphere stratification patterns in the diurnal and seasonal convective cycle of DJF and MAM seasonal time periods during the year of 2016 - 2018. This research supports the implementation of the initial stages in the activity plan Equatorial Line Observation (ELO) as a component of the International Years of Maritime Continent (YMC) program in Indonesia for multi-scale interactions associated with the propagating atmospheric convection. The interaction of MJO and ABWM can be seen from the TRMM data with diurnal convective patterns and the seasonal accumulation compares to rainfall observations resulting a coefficient of 0,80. ERA-Interim reanalysis of resolution 0.25 x 0.25 degree shows the formation of strong eastern winds during the onset of IAM. The Indo-Western Pacific Ocean (IWPO) temperature dynamic mixs the strong diurnal convective that resulted from MJO propagation in the western region that is influenced by nocturnal convective and topographic condition with a daily rainfall range of > 50 mm in the DJF and MAM periods. The ocean stratification patterns that can be seen from the RAMA buoy of subsurface profile data and the reanalysis model with anomaly range of 0.5 - 0.7 celcius, and the condition of mixing layer depth with an average depth of less than 100 meters increase the surface heat flux. The moist ABWM air mass of the onset period is proved by the pattern of the eastern Walker circulation of IWPO.