Penggunaan Empirical Orthogonal Function (EOF) untuk Identifikasi Karakteristik Curah Hujan (Studi Kasus: DAS Ciujung-Cidurian)

Abstract

Rainfall in Indonesia is highly varied in space and time. The purpose of this research was identify spatial and temporal rainfall pattern, examine impact of ENSO on rainfall variability, and obtain the location of stations which had great impact on rainfall variability. The method used Empirical Orthogonal Function (EOF) and Rotated Empirical Orthogonal Function (REOF). From EOF obtained annual and seasonal rainfall variance dominated by monsoon system. Type of mountain topography also contributed on rainfall variability. EOF seasonal temporal patterns related with ENSO. It was seen from high value of correlation between EOF coefficient and SOI. Correlation between EOF1 with MAM, JJA, and SON period respectively -0.467, 0.413, and 0.32. EOF2 correlated with DJF and SON period with correlation respectively -0.555 and -0.588. Rotated Empirical Orthogonal Function (REOF) was used to see the contribution of each observation station by rotating the EOF. Type of rotation is varimax rotation.The result of rotation showed factor1 was determined by two station, Ragas Hilir and Jongjing station whereas other factors were determined by one stasion only.