Soil Moisture Active Passive (SMAP)

Soil Moisture Active Passive (SMAP) is a satellite mission designed to measure the amount of moisture in the Earth's soil. It uses two techniques: active radar and passive radiometry. The active part sends microwave signals to the ground and measures the reflections, helping determine soil wetness even through vegetation. The passive part detects natural microwave emissions from the soil itself. Combining these methods provides accurate, global data on soil moisture levels, which is important for weather forecasting, agriculture, drought monitoring, and understanding water cycles. SMAP helps us better understand and manage Earth's vital water resources.