Abstract ID: 122
The Performance of ECMWF S2S Model on Predicting the Wet Period at the end of 2022 in Java Island, Indonesia
Lead Author: Supari Supari
Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG), Indonesia
Keywords: S2S Prediction, Extreme rainfall, Indonesia
Abstract: At the third dekad of December 2022 (Day 21-31), extreme weather conditions occurred over most of Java Island, Indonesia, which triggered flooding in several districts. In Semarang, Central Java, the rainfall during two consecutive days on 30-31 December 2022 with an accumulation of more than 200 mm/2-days caused massive flooding that inundated most of Semarang City and forced the government to stop operating the trans-Java train services. In general, observational data shows that the accumulated rainfall for 21-31 December is categorized as the above normal in most areas on Java Island. This study aims to evaluate the ability of the ECMWF S2S product in predicting wet anomaly at the third dekad of December 2022 in Java Island. This 10-days time scale is the shortest range of climate services delivered by BMKG, Indonesia Meteorology, Climatology and Geophysics agency. The results show that the model started to capture the signal of this wet period 12 days in advance, marked by a small part of Java Island predicted to experience above-normal rainfall. This signal then looks more obvious in the forecast issued 8 days before the target time when the wet anomaly was predicted over most Java Island. This study implies that much effort are still needed to improve capability of S2S predictions to detect the signal of extreme events at longer lead times. It is also possible that the dekad scale of climate service developed by BMKG reduces the predictability of the event since the daily extreme events are smoothed by the other non-extreme events within that 10-day span.
Co-authors:
Robi Muharsyah, Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG)
Damiana Fitria Kussatiti, Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG)
Amsari Mudzakir Setiawan, Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG)
Adi Ripaldi, Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG)
