Artist's Concept of SMAP |
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| Operator | NASA |
|---|---|
| Mission type | Orbiter |
| Launch date | 2014 [1] |
| Mission duration | 3 years |
| Homepage | NASA's SMAP home page |
| Power | Solar panels |
The Soil Moisture Active Passive mission (SMAP) is in the first tier of missions recommended for NASA by the Earth Science Decadal Survey.[2] It is one of the first Earth observation satellites being developed by NASA in response to the National Research Council’s Decadal Survey.[3] It has been selected for launch in November 2014.
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SMAP will provide measurements of the land surface soil moisture and freeze-thaw state with near-global revisit coverage in 2–3 days. SMAP surface measurements will be coupled with hydrologic models to infer soil moisture conditions in the root zone. These measurements will enable science applications users to:
1) Understand processes that link the terrestrial water, energy and carbon cycles; 2) Estimate global water and energy fluxes at the land surface; 3) Quantify net carbon flux in boreal landscapes; 4) Enhance weather and climate forecast skill; 5) Develop improved flood prediction and drought monitoring capability.
SMAP observations will be acquired for a period of at least three years after launch. A comprehensive validation, science, and applications program will be implemented, and all data will be made available publicly through the NASA archive centers.
The SMAP observatory includes a dedicated spacecraft and instrument suite that will be launched into a near-polar, sun-synchronous orbit on an expendable launch vehicle.
The SMAP measurement system consists of a radiometer (passive) instrument and a synthetic aperture radar (active) instrument operating with multiple polarizations in the L-band range (1.20-1.41 GHz).
The active and passive sensors provide coincident measurements of the surface emission and backscatter. The instruments sense conditions in the top 5 cm of soil through moderate vegetation cover to yield globally mapped estimates of soil moisture and its freeze-thaw state. The combined active and passive measurement approach takes advantage of the spatial resolution of the radar and the sensing accuracy of the radiometer.
The radar and radiometer share a single feed and deployable mesh reflector antenna system (diameter 6 m) that rotates around the nadir axis making conical scans of the surface. The wide swath provides near-global revisit 2–3 days.
SMAP is a directed mission of the National Aeronautics and Space Administration NASA with a target launch date in November 2014. The SMAP project is managed for NASA by the Jet Propulsion Laboratory JPL, with participation by the Goddard Space Flight Center GSFC. SMAP builds on the heritage and risk reduction activities of NASA's ESSP Hydros Mission.[4]
SMAP observations will be used to characterize hydrologic and ecosystem processes including land-atmosphere exchanges of water, energy, and carbon. SMAP soil moisture and freeze-thaw information will directly benefit several societal applications areas, including:
Initialization of numerical weather prediction models and seasonal climate models with accurate soil moisture information will extend forecast lead times and enhance prediction skill.
SMAP soil moisture information will improve the monitoring and forecasting of drought conditions, enabling new capabilities for mitigating drought impacts.
Hydrologic forecast systems calibrated and initialized with high-resolution soil moisture fields will lead to improved flood forecasts and will provide essential information on the potential for landslides.
Soil moisture observations from SMAP will lead to improvements in crop yield forecasts and will enhance the capabilities of crop water stress decision support systems for agricultural productivity.
Improved seasonal soil moisture forecasts will directly benefit famine early warning systems. Benefits will also be realized through improved predictions of heat stress and virus spread rates, and improved disaster preparation and response.
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