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All Journal Pengembangan Inovasi Pertanian Jurnal Penelitian dan Pengembangan Pertanian Jurnal Tanah dan Iklim
Irsal Las
Balai Besar Penelitian dan Pengembangan Sumberdaya Lahan Pertanian
Agriculture, Biological Sciences & Forestry Decision Sciences, Operations Research & Management

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Journal : Jurnal Tanah dan Iklim

 1 
RAINFALL PREDICTION MODELING USING NEURAL NETWORK ANALYSIS TECHNICS AT PADDY PRODUCTION CENTRE AREA IN WEST JAVA AND BANTEN PRAMUDIA, ARIS; KOESMARYONO, Y; LAS, IRSAL; JUNE, T; ASTIKA, I WAYAN; RUNTUNUWU, ELEONORA
Jurnal Tanah dan Iklim (Indonesian Soil and Climate Journal) No 27 (2008): Juli 2008
Publisher : Balai Besar Penelitian dan Pengembangan Sumberdaya Lahan Pertanian

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21082/jti.v0n27.2008.%p

Abstract

Rainfall fluctuates with time and changes randomly, which unfavorable for most of the cropping, such as paddy. An early warning system is required to ensure a productive paddy cropping system. This paper describes the rainfall prediction modelling using a neural network analysis at paddy production centre area in the northern coast of Western Java and Banten. Rainfall data from Baros in the northern coast of Banten, Karawang, and Kasomalang Subang in the northern coast of West Java have been used for setting and validating the model. The model provides rainfall prediction for the next three months (Y=CHt+3), using the inputs data of the number of month (X1=t), the rainfall at the current month (X2=CHt), the rainfall atthe following month (X3=CHt+1), the rainfall at the following two months (X4=CHt+2), the southern ossilation index (SOI) at the current month (X5=SOIt) and the NINO-3,4 sea surface temperature anomaly at the current month (X6=AnoSSTt). Rainfall data recorded in the 1990-2002 period have been used for composing the model, and those in the 2003-2006 periods have been used for validating the model. The validated model has been used to predict rainfall in the 2007-2008. The best modelare those that using a combination of those six input variables. These models are able to explain 88-91% of the data variability with 4-8 mm month-1 of the maximum prediction error. At Baros Serang, the predicted rainfall in the 2007-2008 periods will be varied from Normal to Above Normal. At Karawang and Kasomalang Subang, predicted rainfall will be high at the end of 2007 until early 2008, and then will be low in the middle of 2008 and increases at the end of 2008.
RICE FIELD DISCHARGE MODELLING BY TAKING INTO ACCOUNT THE CONTRIBUTION OF PREVIOUS TERRACE DRAINAGE IRIANTO, GATOT; LAS, IRSAL
Jurnal Tanah dan Iklim (Indonesian Soil and Climate Journal) No 18 (2000): Desember 2000
Publisher : Balai Besar Penelitian dan Pengembangan Sumberdaya Lahan Pertanian

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21082/jti.v0n18.2000.%p

Abstract

Its been a long time that paddy terraces have been used in order to modify local hydraulic characteristics, aiming thus at a better evenness in water collecting and distribution. Nevertheless, the quantification of water transfer mechanism in terraces has still to be fully understood. Research on modeling for water transfer has been carried out to answer this issue.The two following reservoir linear laws have been used to represent water transfer in the terrace: (1) taking into account continuous discharge contribution of the precedent terrace and (2) taking into account discontinuous discharge contribution of the precedent terrace. The results of research show that a universal discharge equation for the nth terrace, based on the reservoir linear law derived through inductive method, can be described as:where : Qn is the discharge from the nth terrace (m3/s), Q0 the initial discharge (m3/s), k is a reservoir constant (s-1),and t is the time(s). According to the physical law, the inflow drained from the previous terrace has to be taken into account, but in this case,discharge modeling is reduced to the time when linear reservoir law still applies. This is because time taken for the terrace to be fully drained-dry would be infinite: thus when the water level is under the drain level axis, the linear reservoir law does not apply anymore. At this time, the main part of the stock can not be computed using surface and water level, because of local surface roughness. To find a solution, the debit was modeled byassuming that water on the terrace was fully drained when the water surface reaches exactly half the diameter of the drain pipe. Results of such a model show that the debit thus evaluated approach the debit measured with a coefficient F (criterion of Nash and Sutcliffe) variegating between 0.97 and 0.98. With such results this model can be accepted, assumingas a basic hypothesis that the terrace is dry when water its surface reaches half of the drain pipe diameter.
Co-Authors Anny Mulyani Aris Pramudia Dedi Nursyamsi Eleonora Runtunuwu Elsa Surmaini Gatot Irianto I Wayan Astika T JUNE Y KOESMARYONO