 |
 |
 |
 |
 |
 |
Sains Malaysiana 38(2):
149-158(2009)
Frequency Analysis of Maximum Daily
Rainfalls via
L-Moment Approach
( Analisis Frekuensi Hujan Harian Maksimum Melalui Kaedah L-Momen )
Ani Shabri & Noratiqah Mohd Ariff Jabatan Matematik, Fakulti Sains, Universiti Teknologi Malaysia 81310 Skudai Johor, Malaysia
Received: 19 May 2008 / Accapted: 12 August 2008
ABSTRACT
Knowledge related to distributions of rainfall amounts are of great importance for the design of water related structures. The greater problem facing hydrologists and engineers identifying the best distribution form for regional data. The main goal of the study is to perform regional frequency analysis of maximum daily rainfalls selected each year among daily rainfalls measured over stations in Selangor and Kuala Lumpur by using the L-moment method. Several distributions were taken into account in this study which include two-parameter normal (NOM), lognormal (LN2), three-parameter lognormal (LN3), logistic (LOG), generalized logistic (GLO), extreme value type I (EV1), generalized extreme value (GEV) and generalized Pareto (GPA) distribution. The most suitable distribution was determined according to the mean absolute deviation index (MADI), mean square deviation index (MSDI) and the L-moment ratio diagram. The result of this study showed that the GLO distribution is the most suitable distribution to fit the data of maximum daily rainfalls for stations in Selangor and Kuala Lumpur. Keywords: Flood frequency; L-moment ratio; maximum daily rainfalls; regional frequency analysis
ABSTRAK
Pengetahuan berkaitan taburan jumlah hujan adalah sangat penting untuk
merekabentuk struktur-struktur yang mempunyai hubungan dengan hidrologi. Masalah utama ahli hidrologi dan jurutera
adalah mengenalpasti bentuk taburan terbaik untuk data serantau. Objektif utama
kajian ini adalah untuk menganalisis frekuensi rantau terhadap data hujan
harian maksimum bagi setiap tahun yang diukur pada stesen-stesen hujan di
Selangor dan Kuala Lumpur menggunakan kaedah L-momen. Beberapa taburan telah diambil kira dalam
kajian ini termasuklah taburan dua-parameter normal (NOM), lognormal (LN2),
tiga-parameter lognormal (LN3), logistik (LOG), logistic teritlak (GLO), nilai
ekstrim Jenis I (EV1), nilai ekstrim teritlak (GEV) dan Pareto teritlak
(GPA). Taburan terbaik bagi mewakili
data untuk setiap stesen ini dikenalpasti melalui sishan indeks min mutlak
(MADI), sisihan indeks min kuasa dua (MSDI) dan rajah nisbah L-momen. Hasil kajian ini mendapati bahawa taburan GLO adalah taburan yang paling
sesuai bagi mewakili data taburan hujan di stesen-stesen Selangor dan Kuala
Lumpur.
Kata kunci: Analisis frekuensi rantau; frekuensi banjir; hujan harian maksimum; nisbah L-momen
REFERENCES
Bobée, B., G. Caradias, F. Ashkar, J. Bernier & P. Rasmussen
1993. Towards a Systematic Approach to Comparing Distributions used in Flood
Frequency Analysis. Journal of Hydraulics 142: 121-136.
Chen, Y.D., Huang, G., Shao, Q. & Xu, C.Y. 2006. Regional analysis of low flow using L-moments for Dongjiang basin, South China. Hydrological Sciences–Journal–des Sciences Hydrologiques 51(6): 1051-1064. Greenwood, J.A., J.M. Landwehr, Matalas, N.C. & Wallis,
J.R. 1979. Probability Weighted Moments: Definition and Relation to Parameters
of Several Distributions Expressible in Inverse Form, Water Resources
Research 15(5): 1049-1054.
Hosking, J.R.M. 1986. The Theory of Probability Weighted Moments, Res. Rep. RC 12210, IBM Research Division, Yorktown Heights.
Hosking, J.R.M. 1990. L-Moments: Analysis and Estimation of
Distributions using Linear Combinations of Order Statistics. Journal of Royal Statistical Society B, 52: 105-124.
Hosking, J.R.M. & J.R. Wallis 1991. Some Statistics
Useful in Regional Frequency Analysis, Res. Rep. RC 17096, IBM Research Division, Yorktown
Heights, NY 10598.
Hosking, J.R.M. & J.R. Wallis 1993. Some Statistics
Useful in Regional Frequency Analysis, Water Resources Research 29, No. 2: 271-281.
Hosking J.R.M. & Wallis, J.R.
1997. Some Statistics Useful in Regional
Frequency Analysis. Res. Rep. RC 17096. IBM Research Division Yorktown Heights:
NY.
Kumar, R., Chatterjee, C., Kumar, S.,
Lohani, A. K. & Singh, R.D. 2003. Development of Regional Flood Frequency Relationships
using L-moments for Middle Ganga Plains Subzone 1(f) of India. Water Resour. Manage. 1: 243–257.
Landwehr, J.M., N.C. Matalas & J.R. Wallis 1978. Some
Comparisons of Flood Statistics in Real and Log Space, Water Resources
Research 14(5): No. 902-920.
Lim, Y. H. & Lye, L. M. 2003. Regional Flood Estimation for Ungauged Basins in Sarawak, Malaysia. Hydrol. Sci. J. 48(1): 79-94. Parida, B. P., Kachroo, R. K.
& Shrestha, D. B. 1998. Regional
Flood frequency Analysis of Mahi-Sabarmati Basin (Subzone 3-a) using index
flood procedure with L-moments. Water Resour. Manage. 12: 1-12.
Rao, A.R. and Hamed, K.H. 2000. Flood Frequency Analysis, Boca Raton, London, New York, Washington,
D.C: CRC Press.
Yurekli, K. 2005. Regional Frequency Analysis of Maximum
Daily Rainfalls Based on L-Moment Approach. GOU.
Ziraat Fakultesi Dersigi, 22(1), 37-44.
|
|||
|
