Investigating the mechanisms of diurnal rainfall variability over Peninsular Malaysia using the non-hydrostatic regional climate model

Ahmad Fairudz Jamaluddin, Fredolin Tangang @ Tajudin Mahmud, Jing Xiang Chung, Ju Neng Liew, Hidetaka Sasaki, Izuru Takayabu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

This study aims to provide a basis for understanding the mechanisms of diurnal rainfall variability over Peninsular Malaysia by utilising the Non-Hydrostatic Regional Climate Model (NHRCM). The present day climate simulations at 5 km resolution over a period of 20 years, from 1st December 1989 to 31st January 2010 were conducted using the six-hourly Japanese re-analysis 55 years (JRA-55) data and monthly Centennial in situ Observation Based Estimates (COBE) of sea surface temperature as lateral and lower boundary conditions. Despite some biases, the NHRCM performed reasonably well in simulating diurnal rainfall cycles over Peninsular Malaysia. During inter-monsoon periods, the availability of atmospheric moisture played a major role in modulating afternoon rainfall maxima over the foothills of the Titiwangsa mountain range (FT sub-region). During the southwest monsoon, a lack of atmospheric moisture inhibits the occurrence of convective rainfall over the FT sub-region. The NHRCM was also able to simulate the suppression of the diurnal rainfall cycle over the east coast of Peninsular Malaysia (EC sub-region) and afternoon rainfall maximum over the Peninsular Malaysia inland-valley (IN sub-region) area during the northeast monsoon. Over the EC sub-region, daytime radiational warming of the top of clouds enhanced atmospheric stability, thus reducing afternoon rainfall. On the other hand, night-time radiational cooling from cloud tops decreases atmospheric stability and increases nocturnal rainfall. In the early morning, the rainfall maximum was confined to the EC sub-region due to the retardation of the north-easterly monsoonal wind by the land breeze and orographic blocking. However, in the afternoon, superimposition of the sea breeze on the north-easterly monsoonal wind strengthened the north-easterly wind, thus causing the zone of convection to expand further inland.

Original languageEnglish
Pages (from-to)1-23
Number of pages23
JournalMeteorology and Atmospheric Physics
DOIs
Publication statusAccepted/In press - 1 Jul 2017

Fingerprint

regional climate
climate modeling
rainfall
atmospheric moisture
monsoon
land breeze
sea breeze
boundary condition
sea surface temperature
warming
convection
cooling
valley
coast
climate
simulation

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Investigating the mechanisms of diurnal rainfall variability over Peninsular Malaysia using the non-hydrostatic regional climate model. / Jamaluddin, Ahmad Fairudz; Tangang @ Tajudin Mahmud, Fredolin; Chung, Jing Xiang; Liew, Ju Neng; Sasaki, Hidetaka; Takayabu, Izuru.

In: Meteorology and Atmospheric Physics, 01.07.2017, p. 1-23.

Research output: Contribution to journalArticle

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