Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 36 km (L2, Passive, Day | Night, Single Channel Algorithm, H Polarization)" layers display surface soil moisture in cm3/cm3 posted on a 36 km EASE-Grid 2.0 derived from the Single Channel Algorithm H-Polarization (SCA-H), one of four optional soil moisture algorithms, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. The variation in the intensity of this radiation depends on the dielectric properties and temperature of the target medium, which for the near surface soil layer is a function of the amount of moisture present. In the SCA-H, the horizontally polarized brightness temperatures are converted to emissivity using a surrogate for the physical temperature of the emitting layer. The derived emissivity is corrected for vegetation and surface roughness to obtain the soil emissivity. The Fresnel equation is then used to determine the dielectric constant. Finally, a dielectric mixing model is used to obtain the soil moisture given knowledge of the soil texture.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture
Data field: soil_moisture_option1
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture (L2, Passive, Day | Night, Single Channel Algorithm, V Polarization)" layer displays surface soil moisture in cm3/cm3 posted on a 36 km EASE-Grid 2.0 derived from the Single Channel Algorithm V-Pol (SCA-V), the baseline soil moisture algorithm, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. The variation in the intensity of this radiation depends on the dielectric properties and temperature of the target medium, which for the near surface soil layer is a function of the amount of moisture present. In the SCA-V, the vertically polarized brightness temperature observations are converted to emissivity using a surrogate for the physical temperature of the emitting layer. The derived emissivity is corrected for vegetation and surface roughness to obtain the soil emissivity. The Fresnel equation is then used to determine the dielectric constant from the soil emissivity. Finally, a dielectric mixing model is used to solve for the soil moisture given knowledge of the soil texture.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture
Data field: soil_moisture_option2
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 36 km (L2, Passive, Day | Night, Dual Channel Algorithm)" layers display surface soil moisture in cm3/cm3 posted on a 36 km EASE-Grid 2.0 derived from the Dual Channel Algorithm (DCA), one of four optional soil moisture algorithms, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. The variation in the intensity of this radiation depends on the dielectric properties and temperature of the target medium, which for the near surface soil layer is a function of the amount of moisture present. In the DCA, both the vertically and horizontally polarized brightness temperatures are used to solve for soil moisture and vegetation optical depth.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture
Data field: soil_moisture_option3
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 9 km (L2, Passive, Day | Night, Single Channel Algorithm, H Polarization)" layers display surface soil moisture in cm3/cm3 derived from the Single Channel Algorithm H-Pol (SCA-H), one of four optional soil moisture algorithms, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. To enhance the grid resolution, Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km EASE-Grid 2.0. In the SCA-H, the horizontally polarized brightness temperatures are converted to emissivity using a surrogate for the physical temperature of the emitting layer. The derived emissivity is corrected for vegetation and surface roughness to obtain the soil emissivity. The Fresnel equation is then used to determine the dielectric constant. Finally, a dielectric mixing model is used to obtain the soil moisture given knowledge of the soil texture.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture
Data field: soil_moisture_option1
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 9 km (L2, Passive, Day | Night, Single Channel Algorithm, V Polarization)" layers display surface soil moisture in cm3/cm3 derived from the Single Channel Algorithm V-Pol (SCA-V), the baseline soil moisture algorithm, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. To enhance the grid resolution, Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km EASE-Grid 2.0. In the SCA-V, the vertically polarized brightness temperature observations are converted to emissivity using a surrogate for the physical temperature of the emitting layer. The derived emissivity is corrected for vegetation and surface roughness to obtain the soil emissivity. The Fresnel equation is then used to determine the dielectric constant from the soil emissivity. Finally, a dielectric mixing model is used to solve for the soil moisture given knowledge of the soil texture.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture
Data field: soil_moisture_option2
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 9 km (L2, Passive, Day | Night, Dual Channel Algorithm)" layers display surface soil moisture in cm3/cm3 derived from the Dual Channel Algorithm (DCA), one of four optional soil moisture algorithms, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. To enhance the grid resolution, Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km EASE-Grid 2.0. In the DCA, both the vertically and horizontally polarized brightness temperatures are used to solve for soil moisture and vegetation optical depth.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture
Data field: soil_moisture_option3
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 36 km (L3, Passive, Day | Night)" layers display a daily global composite of surface soil moisture in cm3/cm3 posted to a 36 km EASE-Grid 2.0 derived from the Single Channel Algorithm V-Pol (SCA-V), the baseline soil moisture algorithm, for the 6:00 a.m. descending (DayAM) and the 6:00 p.m. ascending (NightPM) half-orbit passes of the SMAP radiometer. The SMAP radiometer measures natural thermal emission emanating from the soil surface. The variation in the intensity of this radiation depends on the dielectric properties and temperature of the target medium, which for the near surface soil layer is a function of the amount of moisture present.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture
Data field: soil_moisture
Temporal coverage: 31 March 2015 - present
The Soil Moisture Active Passive (SMAP) "Soil Moisture 9 km (L3, Passive, Day | Night)" layers display a daily global composite of surface soil moisture in cm3/cm3 derived from the Single Channel Algorithm V-Pol (SCA-V), the baseline soil moisture algorithm, for the 6:00 a.m. descending (Day) and the 6:00 p.m. ascending (Night) half-orbit passes of the SMAP radiometer. To enhance the grid resolution, Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km EASE-Grid 2.0. The SMAP radiometer measures natural thermal emission emanating from the soil surface. The variation in the intensity of this radiation depends on the dielectric properties and temperature of the target medium, which for the near surface soil layer is a function of the amount of moisture present.
The SMAP spacecraft carries two instruments, a radar (active) and a radiometer (passive), that together make global measurements of land surface soil moisture and freeze/thaw state. It is useful for monitoring and predicting natural hazards such as floods and droughts, understanding the linkages between Earth’s water, energy and carbon cycles, and reducing uncertainties in predicting weather and climate.
References: SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture
Data field: soil_moisture