TEMPORAL AND SPATIAL ANALYSIS OF EXTREME RAINFALL ON THE SLOPE AREA OF MT. MERAPI
Abstract: Rainfall has
temporal and spatial characteristics with certain pattern which are affected by
topographic variations and climatology of an area. The intensity of extreme
rainfall is one of important characteristics related to the trigger factors for
debris flow. This research will discuss the result of analysis on short
duration rainfall data in the south and west slope of Mt. Merapi. Measured
hourly rainfall data in 14 rainfall stations for the last 27 years were used as
analysis input. The rainfall intensity-duration-frequency relationship (IDF)
was derived using empirical formula of Sherman, Kimijima, Haspers, and Mononobe
method. The analysis on the characteristics of extreme rainfall intensity was
performed by conducting spatial interpolation using Inverse Distance Weighted
(IDW) method.
Result of analysis shows that IDF of rainfall in the research area fits
to Sherman’s formula. Besides, the spatial distribution pattern of maximum
rainfall intensity was assessed on the basis of area rainfall. Furthermore, the
difference on the result of spatial map for one hour extreme rainfall based on
isolated event and non-isolated event method can be evaluated. The result of
this preliminary research is expected to be inputs in the establishment of
debris flow early warning in Mt. Merapi slope area.
Penulis: Dhian Dharma Prayuda
Journal Code: jptsipilgg120042