MODEL ANALISIS PRAKIRAAN DAN VALIDASI CURAH HUJAN DI KABUPATEN TEGAL

Analysis Model of Rainfall Forecast a Validation in Tegal Regency

Abstrak

Central Java is classified as a wet tropical area. Characteristics of the climate is extremely influenced by the evolution which happened in the sea, primary in Pacific and Atlantic Ocean, also influenced by the atmosphere change that available,  so that the climate is  fluctuating easily and it  is difficult estimated. The other factors which influence  the appearance of the high mounts in same areas such as Merbabu, Merapi, Sumbing, sindoro and excetera. The methods, we use in this rainfall forecast, Characterize stochastic by apllicating data time series are based on on historical observation. The data sources that are combined with change indicator  and climate deviation,  in this ccse anomaly by sea surface temperature (SST) of sone Nino 3.4 can be seen in the picture I. From the data collected then they are analyzed by application  EXCEL Program, Mini tab, Macro retrieve and Regresion Macro. Simulation  re• sult show that analysis  result of rainfall forecast (estimated rainfall) from the month of Janu• ary - June 2002 in the 33 location  points of station.  Rainfall available in  Tega! regency is conditioned normally up to above normal with forecast of the rainfall average 1961,1 mm. From the forrecast average, the rainfall in January places  in the highest anomally is number 569,36 mm in a row; February 491,64  mm; March 391,33  mm; April  245,1;   May 153,6  mm and June 105,7 mm.  Simulation result of rainfall validation  (actual rain) that happened  in January 496,3 mm; March 469,3 mm; April 174,9 mm; May 74,6 mm and June 55,75 mm. But, in February the frequency of the highest rainfall above normal  is 717,2 mm. Result of this simulation  between forecast and actually do not result in deviation so far, but commonly it identifies rainfall for Tegal Regency still normal.