Rain Behaviour at Mt. Merapi Area as Observed by XMPR and ARR
Short duration rainfall information has now become one of many important aspects to support the development of warning criteria for disaster mitigation. Similar importance is also found in the development of warning criteria against the lahar flow disaster at Mt. Merapi area. The rainfall information obtained from the radar observation has also become a new challenge for the last decade in line with the rapid growth of information and communication technology. However, the accuracy of its estimation needs to be evaluated by considering the correlation between radar rainfall and rain gauge rainfall. In case of radar rainfall can be precisely estimated, this information will contribute to generating appropriate warning criteria. This study was carried out as the first attempt to evaluate the rainfall information as performed by the X-Band Multi Parameter Radar (XMPR) that was installed at Mt. Merapi in the mid-August 2015. Several ground rainfall data obtained from Automatic Rainfall Recorder (ARR) have been adopted to analyze the aforesaid radar rainfall information, and estimated errors between the two are presented. Evaluation of the radar estimated error value as a function or range is taken through a Fractional Standard Error (FSE) index that quantifies the differences between ground rainfall measurement (G) and radar rainfall estimation (R), also the G/R ratio characteristics. The result shows there was a poor correlation between radar estimated and rain gauge measured rainfall located over 14 km from radar. Radar bias (M) is suitable for correcting radar rainfall amount, yet inappropriate for fractional values.
Djoko Legono, Radianta Triatmaja, Prof. Priyosulistyo, Veerasak Likhitruangsilp, Lim Pang Zen, Teuku Faisal Fathani, Ali Awaludin, Intan Supraba, Imam Muthohar, Dr. Endita, Fikri Faris and Dr. Inggar Septhia Irawati
R. Hambali et al., "Rain Behaviour at Mt. Merapi Area as Observed by XMPR and ARR", Applied Mechanics and Materials, Vol. 881, pp. 34-41, 2018