EVALUATION OF SUBSEASONAL TO SEASONAL (S2S) PRECIPITATION FORECAST PERFORMANCE FROM NMME-2 MODEL OVER INDONESIA

• Main Author: Nugraha, Dwina
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/76983
• Institution: Institut Teknologi Bandung

Subseasonal to Seasonal (S2S) precipitation forecast as a bridge for the gap between weather and seasonal forecast, can be utilized as supporting information for decision-making related to hydrometeorological disaster mitigation activities. However, uncertainty in global models caused forecast performance can be different across regions and time periods. Therefore, it is important to evaluate forecast performance before utilizing the prediction result in Indonesia. In this study, the performance of probabilistic precipitation forecast from the Multi-model Ensemble (MME) of three models in the North American Multi- Model Ensemble phase 2 (NMME-2) project was evaluated. The evaluation was conducted during the Boreal Summer (May - October) and Boreal Winter (November - April) periods, as well as during the active period of subseasonal climate variability phenomenon Madden Julian Oscillation (MJO). The results show, Subseasonal to Seasonal (S2S) precipitation forecast from the Multi-model Ensemble (MME) of three models in the North American Multi- Model Ensemble phase 2 (NMME-2) project are sufficiently accurate and reliable during the Boreal Summer period for Central Sumatra, Southern Sumatra, Southern Kalimantan, Java, Southern Sulawesi, and Southern Papua regions, with a range of CRPS values between 4-16 mm/7 days and a reliability category of "perfect". There is no significant difference in the performance of S2S precipitation forecast between the active and inactive events of the Madden Julian Oscillation (MJO). The difference in CRPS values between these two periods is only around 0.8-1.2 mm/7 days, and there is no difference in reliability categories across Indonesia as a whole, nor significant spatial pattern differences. Based on these findings, the S2S rainfall predictions from the NMME-2 model have the potential to be utilized as supporting information for hydro-meteorological disaster mitigation activities in several regions of Indonesia.