This study established a methodology for the application of downscaling technique in a mountainous area having large
spatial variations of rainfall and tried to estimate the change of rainfall characteristics in the future under climate change
using the established method. The Namhan river basin, which is in the mountainous area of the Korean peninsula, has been
chosen as the study area. Artificial Neural Network - Simple Kriging with varying local means (ANN-SKlm) has been
built by combining artificial neural network, which is one of the general downscaling techniques, and SKlm technique,
which can reflect the geomorphologic characteristics like elevation of the study area. The evaluation of SKlm technique was
done by using the monthly rainfalls at six weather stations which KMA(Korea Meteorological Administration) is managing
in the basin. The ANN-SKlm technique was compared with the Thiessen technique and ordinary kriging(OK) technique.
According to the evaluation result of each technique the SKlm technique showed the best result.