FRACTAL AND CYCLIC OF THE HIDROMETEOROLOGY IN THE CITARUM RIVER BASIN

JTM VOLUME XIV NO1./2007

# FRACTAL AND CYCLIC OF THE HIDROMETEOROLOGY IN THE CITARUM RIVER BASIN
# by Ruminta* The Houw Liong** Bayong Tjasyono***
# * Laboratorium Klimatologi Fakultas Pertanian UNPAD. ** Program Studi Fisika - FMIPA - ITB. *** Program Studi Meteorologi – FIKTM - ITB.

# Abstract

An investigations on the fractal and cyclic the hydrometeorology had been carried out in the Citarum river basin. The investigations used monthly observations data there are rainfall, evapotranspiration, humidity, and runoff (1968 to 2000). In this investigations indicated that hydrometeorological processes in the Citarum river basin was low-dimension chaos ( correlation dimension, ν<4). The ν-values of the rainfall, evapotranspiration, humidity, and runoff are 1.83, 1.68, 1.23, and 2.05 respectively that showed a minimum numbers of the main variables in the dynamic model of the hidrometeorological processes are 2, 2, 2, and 3 respectively. The rainfall and runoff are chaotic mono-fractal (qD<2) that showed deterministic processes but the evapotranspiration and humidity are chaotic multi-fractal (qD>2) that showed stochastic processes. The extreme values of the rainfall, evapotranspiration, humidity, and run off had return periods more than 170, 50, 30, and 80 months respectively. The rainfall and runoff had the same two main cyclic there are 6 and 12 monthly but the evapotranspiration and humidity had one main cyclic there are 12 and 16 monthly respectively. The hydrometeorological processes in the Citarum river basin was the results of the unbounded cascade processes because that had the value of exponent spectrum less than one.

Keywords : hydrometeorology, fractal, correlation dimension, return period, cyclic, exponent spectrum