Rainfall modeling based on early predicted and season zone characteristic in the BMKG season zone over Lombok river basin

Abstract

Planning water resources for long-term (annual, monthly) and operational (daily) requires a more accurate analysis of water availability calculations. The Meteorology, Climatology and Geophysics Agency (BMKG) publishes bulletin of forecasting every year in the form of the early wet season and the characteristics of the wet and dry season in each Season Zone (ZOM). BMKG conducts analysis and forecasting with complex climate parameters. Thomas Fiering analysis with the help of Excel Visual Basic Application (VBA) software is used to forecast rainfall at each rainfall station in BMKG Season Zone. The average error of forecasting rainfall during the wet season on the BMKG season zone in 2015/2016, 2016/2017 and 2017/2018 were 20%, 30% and 26%. While the average error for the dry season on the BMKG season zone is 44%, 34% and 52%. The existence of this deviation is caused by several factors including the uncertain season changes every year, as well as the influence of "El Nino.".