An orbiting observatory that measures the amount of water in the top 5 cm (2 inches) of soil everywhere on Earth’s surface will soon be placed in a polar orbit around Earth. It is called SMAP. This is an acronym made from the name of the satellite. SMAP stands for Soil Moisture Active Passive. A detailed description can be found in the SMAP Handbook (PDF, 4.09 MB). The topsoil layer is the one in which the food we eat grows and where other vegetation lives. Moisture in the soil indirectly affects us in a variety of ways. In the course of its observations, SMAP will also determine if the ground is frozen or thawed in colder areas of the world. SMAP is designed to measure soil moisture over a three-year period, every 2-3 days. This permits changes, around the world, to be observed over time scales ranging from major storms to repeated measurements of changes over the seasons.
NASA
NASA/JPL/SMAP
2017-06-12 14:38:54.0 [sritz] update Definition (An orbiting observatory that measures the amount of water in the top 5 cm (2 inches) of soil everywhere on Earth’s surface will soon be placed in a polar orbit around Earth. It is called SMAP. This is an acronym made from the name of the satellite. SMAP stands for Soil Moisture Active Passive. A detailed description can be found in the SMAP Handbook (PDF, 4.09 MB). The topsoil layer is the one in which the food we eat grows and where other vegetation lives. Moisture in the soil indirectly affects us in a variety of ways. In the course of its observations, SMAP will also determine if the ground is frozen or thawed in colder areas of the world. SMAP is designed to measure soil moisture over a three-year period, every 2-3 days. This permits changes, around the world, to be observed over time scales ranging from major storms to repeated measurements of changes over the seasons.);
2017-06-12 14:37:54.0 [sritz] update Definition (Objectives: SMAP will provide global measurements of soil moisture and its freeze/thaw state. These measurements will be used to enhance understanding of processes that link the water, energy and carbon cycles, and to extend the capabilities of weather and climate prediction models. SMAP data will also be used to quantify net carbon flux in boreal landscapes and to develop improved flood prediction and drought monitoring capabilities. Observatory: The SMAP observatory employs a dedicated spacecraft with an instrument suite that will be launched on an expendable launch vehicle into a 680-km near-polar, sun-synchronous orbit, with equator crossings at 6 am and 6 pm local time. Instrument: The SMAP instrument includes a radiometer and a synthetic aperture radar operating at L-band (1.20-1.41 GHz). The instrument is designed to make coincident measurements of surface emission and backscatter, with the ability to sense the soil conditions through moderate vegetation cover. The instrument measurements will be analyzed to yield estimates of soil moisture and freeze/thaw state. The antenna scan has a swath width of 1000 km providing global coverage within 3 days at the equator and 2 days at boreal latitudes (>45 degrees N). Operations: SMAP science measurements will be acquired for a period of three years. A comprehensive validation program will be carried out after launch to assess the accuracies of the soil moisture and freeze/thaw estimates. Data products from the SMAP mission will be made available through the NASA archive centers.); update Definition ([Text Source: NASA SMAP home page, https://smap.jpl.nasa.gov/ ]);