Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004

This study investigated the spatial pattern and trends of the daily rainfall data in Peninsular Malaysia based on seasonal rainfall indices. Five rainfall indices which describe the main characteristics of rainfall, the total amount of rainfall, frequency of wet days, rainfall intensity, extreme fre...

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Main Authors:	Jamaludin Suhaila, Sayang Mohd Deni, Wan Zawiah Wan Zin, Abdul Aziz Jemain
Format:	Article
Language:	English
Published:	Universiti Kebangsaan Malaysia 2010
Online Access:	http://journalarticle.ukm.my/7369/ http://journalarticle.ukm.my/7369/ http://journalarticle.ukm.my/7369/1/01_Md_Yeaminhossain.pdf

id	ukm-7369
recordtype	eprints
spelling	ukm-73692016-12-14T06:43:52Z http://journalarticle.ukm.my/7369/ Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004 Jamaludin Suhaila, Sayang Mohd Deni, Wan Zawiah Wan Zin, Abdul Aziz Jemain, This study investigated the spatial pattern and trends of the daily rainfall data in Peninsular Malaysia based on seasonal rainfall indices. Five rainfall indices which describe the main characteristics of rainfall, the total amount of rainfall, frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity, were employed in this study. The statistics of rainfall indices were calculated in terms of their means for four regions in Peninsular Malaysia for the period 1975 to 2004. The findings indicate that the southwest monsoon had the greatest impact on the western part of the Peninsula, particularly in characterizing the rainfall pattern of the northwest region. During this season, the northwest region could be considered as the wettest region since all rainfall indices tested are higher than in other regions of the Peninsula. Otherwise, the northwest region is denoted as the driest part of the Peninsula during the northeast monsoon period. The northwest region is less influenced by the northeast monsoon because of the existence of the Titiwangsa Range, which blocks the region from receiving heavy rainfall. On the other hand, it is found that the lowlands areas such as the eastern part of the Peninsula are strongly characterized by the northeast monsoonal flow. Based on the results of the Mann-Kendall test, as the trend of the total amount of rainfall and the frequency of wet days during the southwest monsoon decrease at most of the stations, the rainfall intensity increases. In contrast, increasing trends in both the total amount of rainfall and the frequency of wet days were observed at several stations during the northeast monsoon, which give rise to the increasing trend of rainfall intensity. The results for both seasons indicate that there are significantly decreasing trends in the frequency of wet days during the extreme events for most of the stations on the peninsula. However, a smaller number of significant trends was found for extreme intensity. Universiti Kebangsaan Malaysia 2010-08 Article PeerReviewed application/pdf en http://journalarticle.ukm.my/7369/1/01_Md_Yeaminhossain.pdf Jamaludin Suhaila, and Sayang Mohd Deni, and Wan Zawiah Wan Zin, and Abdul Aziz Jemain, (2010) Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004. Sains Malaysiana, 39 (4). pp. 533-542. ISSN 0126-6039 http://www.ukm.my/jsm/english_journals/vol39num4_2010/contentsVol39num4_2010.html
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Kebangasaan Malaysia
building	UKM Institutional Repository
collection	Online Access
language	English
description	This study investigated the spatial pattern and trends of the daily rainfall data in Peninsular Malaysia based on seasonal rainfall indices. Five rainfall indices which describe the main characteristics of rainfall, the total amount of rainfall, frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity, were employed in this study. The statistics of rainfall indices were calculated in terms of their means for four regions in Peninsular Malaysia for the period 1975 to 2004. The findings indicate that the southwest monsoon had the greatest impact on the western part of the Peninsula, particularly in characterizing the rainfall pattern of the northwest region. During this season, the northwest region could be considered as the wettest region since all rainfall indices tested are higher than in other regions of the Peninsula. Otherwise, the northwest region is denoted as the driest part of the Peninsula during the northeast monsoon period. The northwest region is less influenced by the northeast monsoon because of the existence of the Titiwangsa Range, which blocks the region from receiving heavy rainfall. On the other hand, it is found that the lowlands areas such as the eastern part of the Peninsula are strongly characterized by the northeast monsoonal flow. Based on the results of the Mann-Kendall test, as the trend of the total amount of rainfall and the frequency of wet days during the southwest monsoon decrease at most of the stations, the rainfall intensity increases. In contrast, increasing trends in both the total amount of rainfall and the frequency of wet days were observed at several stations during the northeast monsoon, which give rise to the increasing trend of rainfall intensity. The results for both seasons indicate that there are significantly decreasing trends in the frequency of wet days during the extreme events for most of the stations on the peninsula. However, a smaller number of significant trends was found for extreme intensity.
format	Article
author	Jamaludin Suhaila, Sayang Mohd Deni, Wan Zawiah Wan Zin, Abdul Aziz Jemain,
spellingShingle	Jamaludin Suhaila, Sayang Mohd Deni, Wan Zawiah Wan Zin, Abdul Aziz Jemain, Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
author_facet	Jamaludin Suhaila, Sayang Mohd Deni, Wan Zawiah Wan Zin, Abdul Aziz Jemain,
author_sort	Jamaludin Suhaila,
title	Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
title_short	Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
title_full	Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
title_fullStr	Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
title_full_unstemmed	Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
title_sort	trends in peninsular malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004
publisher	Universiti Kebangsaan Malaysia
publishDate	2010
url	http://journalarticle.ukm.my/7369/ http://journalarticle.ukm.my/7369/ http://journalarticle.ukm.my/7369/1/01_Md_Yeaminhossain.pdf
first_indexed	2023-09-18T19:49:31Z
last_indexed	2023-09-18T19:49:31Z
_version_	1777406125355827200

Trends in Peninsular Malaysia rainfall data during the southwest monsoon and northeast monsoons seasons: 1975-2004

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