GSMaP Seasonal Rainfall Verification Over Western Java

West Java, the most developed region in Indonesia, faced a great challenge in handling hydrological issues such as water supply (crops production, municipal water system, etc.) and hydrometeorological hazards (flood, erosion, etc.). Continuous large-scale rainfall estimation is crucial to handle hydrological issues, which is provided by a high-resolution rainfall satellite product such as GSMaP. However, the quality of GSMaP remains unclear since it lacks ground-based verification. Widely distributed rain gauge network in West Java with almost 38 stations from PUSAIR and 12 stations from Meteorology and Geophysics is used to verify the quality of GSMaP. Based on ground observation, in the southern of West Java, the first peak of rainfall pattern occurs in November while in the northern coastal area of West Java. Spatially from GSMaP data also shows the same thing where in November there is a fairly high intensity of rain in the southern region of West Java. Therefore, the conditions are detected both from ground observation and GSMaP thus rainfall seasonal variability of West Java is also captured. Although GMaPs magnitude underestimated rainfall mainly in the southern region of West Java, the GSMaP data is adequate to understand the pattern and variability of rainfall over West Java.