Seasonal Dependence of Cold Surges and their Interaction with the Madden–Julian Oscillation over Southeast Asia

Xavier, Prince and Lim, See Yee and Ammar Bin Abdullah, Muhammad Firdaus and Bala, Michael and Chenoli, Sheeba Nettukandy and Handayani, Asteria S. and Marzin, Charline and Permana, Donaldi and Tangang, Fredolin and Williams, Keith D. and Yik, Diong Jeong (2020) Seasonal Dependence of Cold Surges and their Interaction with the Madden–Julian Oscillation over Southeast Asia. Journal of Climate, 33 (6). pp. 2467-2482. ISSN 0894-8755

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Official URL: https://doi.org/10.1175/JCLI-D-19-0048.1

Abstract

Northeasterly cold surges strongly influence the rainfall patterns over the Malay Peninsula during the northeast monsoon season. This study looks at the changes in the cold surges and Madden–Julian oscillation (MJO) characteristics through the northeast monsoon season and their interaction. Nearly 75% of the cold surge events tend to cross the equator around the Java Sea area (1008–1108E) in February–March with drier conditions prevailing over the Malay Peninsula and increased rainfall over Java. Both the cold surges and the MJO undergo seasonal variations with well-defined regional features. Wavelet analysis shows that MJO amplitude and high-frequency rainfall variations over Southeast Asia peak in November–December. MJO amplitude is suppressed during February and March. This is linked to the high-frequency surges of meridional winds that are prominent during the early part of the season, but February–March is dominated by low-frequency (;20–90 days) cross-equatorial monsoon flow. These prolonged periods of strong meridional flow at the equator interact with the MJO both dynamically and thermodynamically and act as a barrier for convection from propagating from the Indian Ocean to the Maritime Continent (MC). These interactions may have implications for weather and seasonal forecasting over the region. An evaluation of the properties of cold surges and their interaction with the seasonal cycle in the Met Office Unified Model is performed. The atmosphere–ocean coupled model performs better in representing the pattern of influence of the cold surges despite the biases in intensity and spatial distribution of rainfall extremes. These diagnostics are presented with the aim of developing a set of model evaluation metrics for global and regional models. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Item Type: Article
Uncontrolled Keywords: High frequency HF; High frequency surges; Maritime Continent; Rainfall extremes; Rainfall variation; Seasonal dependence; Seasonal forecasting; Seasonal variation
Subjects: G Geography. Anthropology. Recreation
G Geography. Anthropology. Recreation > G Geography (General)
Divisions: Faculty of Arts and Social Sciences
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 26 Feb 2021 07:56
Last Modified: 26 Feb 2021 07:56
URI: http://eprints.um.edu.my/id/eprint/25787

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