Madden–Julian Oscillation and the Winter Rainfall in Taiwan

Abstract

This study discusses major impacts of the Madden-Julian oscillation (MJO) on the winter (NovemberApril) rainfall in Taiwan. The results show that Taiwan has more rainfall in MJO phases 3 and 4 (MJO convectively active phase in the Indian Ocean and the western part of the Maritime Continent), and less rainfall in phases 7 and 8 (the western Pacific warm pool area). Mechanisms associated with the MJO are suggested as follows. 1) The tropics to midlatitude wave train: when the MJO moves to the middle Indian Ocean, a Matsuno-Gill-type pattern is induced. The feature of this tropical atmospheric response to the MJO diabatic heating is a pair of upper-level anomalous anticyclones symmetric about the equator to the west of the heating. The northern anomalous anticyclone over the Arabian Sea and northern India induces a northeastward-propagating wave train to the midlatitudes. The wave pattern consists of a cyclonic anomaly centered at East Asia that enhances the winter rainfall in Taiwan. 2) Increase of moisture supply from the South China Sea: when the MJO convection approaches Sumatra and Java of the Maritime Continent, the eastward penetration of equatorial convection enhances a low-level southerly flow that transports the moisture northward to Taiwan and southern China. As a consequence, with the increase of moisture supply from the south, more winter monsoon rainfall is observed in Taiwan.

Influence of the Madden–Julian oscillation on Tibetan Plateau snow cover at the intraseasonal time-scale

“…In this article, the MJO states are tracked by the daily all-season real-time multivariate MJO (RMM) index proposed by Wheeler and Hendon 47 . The RMM index has been widely applied to diagnose the influence of the MJO on various weather and climate systems 25 26 29 30 34 36 40 41 42 43 44 45 . The RMM index describes a MJO cycle that generally progresses eastward from phase 1 to phase 8.…”

“…The MJO has planetary-scale signals in atmospheric circulation systems coupled with deep convection and propagates eastwards slowly (~5 m/s) from the Indian Ocean to the Pacific Ocean 22 . During its eastward propagation, the circulation anomalies associated with the MJO interact with various weather and climate systems 23 , affecting precipitation 24 25 26 27 28 29 30 , monsoons 31 32 33 , temperature 28 34 , tropical cyclones 35 36 , El Niño–Southern Oscillation 37 38 39 , polar circulations 40 41 42 , Arctic sea ice 43 and snowpack 44 45 . However, compared to other weather and climate systems, few studies have focused on the MJO-related intraseasonal variability of snow cover on the TP.…”

Boreal Summer Intraseasonal Oscillation Impact on Western North Pacific Typhoons and Rainfall in Taiwan

“…2c, f, and i. According to several previous studies regarding the MJO and the monsoon, the moisture supply can be a very important mechanism that results in increasing local rainfall (Jia et al 2011;Hung et al 2014). Therefore, the low-level 850 hPa moisture convergence/divergence is calculated using the velocities multiplying the specific humidity (uqi and vqj; where q is the specific humidity), and the composites are made based on each phase of BSISO2 to verify the moisture supply associated with the BSISO (Fig.…”

“…The MJO impact on Taiwan rainfall in the winter-half season was also investigated in Hung et al (2014). In contrast, not many studies focused on the local ISO impact on the summer typhoon season in Taiwan.…”

On the relationship between the Madden‐Julian Oscillation and 2 m air temperature over central Asia in boreal winter

“…It has been connected to various atmospheric phenomena. In the tropics, the MJO is related to the El Niño-Southern Oscillation [e.g., Kessler and Kleeman, 2000;McPhaden et al, 2006;Kapur and Zhang, 2012], the Indian monsoon [e.g., Lau and Chan, 1986;Saith and Slingo, 2006], the North American monsoon system [Higgins and Shi, 2001], the activity of tropical cyclones [e.g., Kim et al, 2008;Camargo et al, 2008;Slade and Maloney, 2013], and the rainfall over tropical areas [e.g., Hung et al, 2014]. In the extratropics, the MJO can affect the Arctic and Antarctic oscillations [e.g., Zhou and Miller, 2005;L'Heureux and Higgins, 2008;Flatau and Kim, 2013], and the rainfall in the East Asia [e.g., Jia et al, 2011;He et al, 2011He et al, ].…”