Sains Malaysiana 43(3)(2014): 359–367

Pemodelan Hujan Denyut Segi Empat Neyman Scott (NSRP) Terbaik di Semenanjung Malaysia

(The Best Neyman Scott Rectangular Pulse (NSRP) Rainfall Modelling in Peninsular Malaysia)

RADO YENDRA¹*, WAN ZAWIAH WAN ZIN² & ABDUL AZIZ JEMAIN²

¹Department of Mathematics, Faculty of Science and Mathematics

Universitas Islam Negeri Sultan Syarif Kasim Riau, 28293 Pekanbaru, Riau, Indonesia

²School of Mathematical Sciences, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

Diserahkan: 7 Februari 2013/Diterima: 12 Julai 2013

ABSTRAK

Kajian ini bertujuan mendapatkan gabungan statistik untuk pemodelan hujan kelompok berstokastik Denyut Segi Empat Neyman-Scott (NSRP) yang mampu memberikan pemadanan terbaik bagi hujan di stesen hujan Semenanjung Malaysia. Enam set gabungan statistik, yang setiap setnya mengandungi gabungan statistik momen (1, 2 dan 3) dan kebarangkalian hujan dalam selang masa yang singkat (jam) dan panjang (harian), serta empat taburan yang berbeza bagi kelebatan sel hujan (Eksponen, Campuran Eksponen, Gamma dan Weibull) telah dikaji. Penyelidikan telah dilakukan ke atas sembilan stesen hujan yang mewakili rantau yang berbeza di Semenanjung Malaysia. Hasil mendapati bahawa statistik momen ke-3 (kepencongan) tidak memberikan sumbangan yang baik dalam menjayakan model. Selang masa 1, 6 dan 24 jam didapati yang terbaik bagi statistik momen kedua (variasi) bagi menjayakan model. Kajian ini juga mendapati bahawa taburan eksponen adalah yang terbaik bagi pemodelan hujan NSRP di Semenanjung Malaysia.

Kata kunci: Eksponen; gamma; Neyman-Scott; statistik momen; Weibull

ABSTRACT

In this paper, a study to determine the best combination of statistics for stochastic Neyman-Scott Rectangular Pulse (NSRP) rainfall modeling had been carried out. Six sets of statistics, each of which contains a combination of statistical moments (1, 2 and 3) and the probability of rain in short time intervals (h) and long term (daily), as well as four different distributions (Exponential, Exponential mixture, Gamma and Weibull) for rain cell intensity were used and implemented on hourly rainfall data at nine stations representing different regions of Peninsular Malaysia. The study shows that the third moment statistics (skewness) did not give significant contribution to the success of the model. On the other hand, the time interval 1, 6 and 24 h are the best for the second moment statistics (variation). This study also found that the exponential model is the best distribution for modeling NSRP rainfall in Peninsular Malaysia.

Keywords: Exponent; gamma; Neyman-Scott; statistics moment; Weibull

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*Pengarang untuk surat menyurat; email: yendra_75@yahoo.com.sg