Evaluation of Seasonal, Drought, and Wet Condition Effects on Performance of Satellite-Based Precipitation Data over Different Climatic Conditions in Iran

The Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation (GPM) are the most important widely used data sources in several applications—e.g., forecasting drought flood, managing water resources—especially areas with sparse or no other robust sources. This study explored accuracy precision of satellite products over a span 18 years (2000–2017) using synoptic ground station for three regions Iran different climates, namely (a) humid high rainfall, (b) semi-arid, (c) arid. results show that monthly precipitation GPM TRMM overestimate rainfall. On average, they overestimated amount by 11% humid, 50% 43% arid climate conditions compared to ground-based data. also evaluated wet based on standardized index (SPI) seasons. showed varies significantly under drought, wet, normal timescales, being lowest conditions, especially regions. highest was obtained 12-month timescale 3-month timescale. Although is dependent season, seasonal effects depend climatic conditions.