Sains Malaysiana
39(3)(2010): 387–393
Finding
the Best Circular Distribution for Southwesterly
Monsoon
Wind Direction in Malaysia
(Menentukan
Taburan Berarah Terbaik bagi Data Arah Angin Barat Daya di Malaysia)
Nur
Arina Basilah Kamisan, Abdul Ghapor Hussin* & Yong Zulina Zubairi
Centre
for Foundation Studies in Science, University of Malaya 50603 Kuala Lumpur, Malaysia
Diserahkan:
12 Jun 2009 / Diterima: 27 Ogos 2009
ABSTRACT
In
this paper, four types of circular probability distribution were used to
evaluate which circular probability distribution gives the best fitting for
southwesterly Malaysian wind direction data, namely circular uniform
distribution, von Mises distribution, wrapped-normal distribution and
wrapped-Cauchy distribution. The four locations chosen were Alor Setar, Langkawi,
Melaka and Senai. Two performance indicators or goodness of fit tests which are
mean circular distance and chord length were used to test which distribution
give the best fitting.
Keywords: Circular probability
distribution; chord length; directional data; goodness of fit test; mean
circular distance
ABSTRAK
Dalam
kajian ini, empat jenis taburan kebarangkalian berarah telah digunakan untuk
melihat taburan yang memberikan keserasian yang terbaik dengan data arah angin
di Malaysia. Taburan tersebut adalah taburan berarah seragam, taburan von
Mises, taburan normal–menggulung dan taburan Cauchy-menggulung. Empat lokasi di
Malaysia telah dipilih untuk kajian ini iaitu di Alor Setar, Langkawi, Melaka
dan Senai. Dua jenis penentu prestasi iaitu jarak min membulat dan panjang
perentas telah digunakan untuk melihat taburan yang memberikan prestasi
terbaik.
Kata
kunci: Data berarah; jarak min membulat; panjang perentas; taburan
kebarangkalian berarah; ujian keserasian Terbaik
RUJUKAN
Henry,
C.T. 2002. Testing for Normality. New York: Marcel Dekker.
Jamalamadaka,
S.R. & SenGupta A. 2001. Topics in Circular Statistics. Singapore:
World Scientific Publishing Co. Pte. Ltd.
Mardia,
K.V. & Jupp, P. E. 1999. Directional Statistics. England: John
Wiley, Chichester.
*Corresponding
author; email: ghapor@um.edu.my