Temporal coverage: 13 April 2015 - 7 July 2015
The Soil Moisture Active Passive (SMAP) “Sigma0 3 km (L3, Active, HH Polarization)", "Sigma0 3 km (L3, Active, VV Polarization)" and "Sigma0 3 km (L3, Active, XPOL Polarization)” layers displays backscatter from the SMAP radar in decibels (dB) posted on a 3 km EASE-Grid 2.0 for the horizontal transmit and horizontal receive (HH) polarizations, vertical transmit and vertical receive (VV) polarizations, and the cross (XPOL) polarization. Backscatter is the portion of the outgoing radar signal that the target redirects directly back towards the radar antenna. Sigma0 (Sigma nought), the backscatter coefficient, is the normalized measure of the radar return from a distributed target, defined per unit area on the ground.
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 Radar Global Daily 3 km EASE-Grid Soil Moisture
Data fields: sigma0_hh_mean, sigma0_vv_mean, sigma0_xpol_mean
Temporal coverage: 13 April 2015 - 7 July 2015
The Soil Moisture Active Passive (SMAP) "Sigma0 3 km QA (L3, Active, HH Polarization)", "Sigma0 3 km QA (L3, Active, VV Polarization)" and "Sigma0 3 km QA (L3, Active, XPOL Polarization" layers display quality assurance (QA) flags for Sigma0 backscatter from the SMAP radar for the horizontal (H) transmit and horizontal (H) receive polarizations, the vertical (V) transmit and the vertical (V) receive polarizations, and the cross-polarizations (XPOL).
Within the image, green indicates that Sigma0 observations have acceptable quality for science use, yellow indicates that caution should be used with the Sigma0 observations as one or more quality-impacting conditions have been identified, and red indicates that Sigma0 observations are flagged as bad due to unacceptable quality.
The Soil Moisture Active Passive (SMAP) "Sigma0 3 km RFI (L3, Active, HH Polarization)", "Sigma0 3 km RFI (L3, Active, VV Polarization)" and "Sigma0 3 km RFI (L3, Active, XPOL Polarization" layers display Radio Frequency Interference (RFI) quality flags of backscatter posted on a 3 km EASE-Grid 2.0 for the horizontal transmit and the horizontal receive (HH) polarizations, the vertical transmit and the vertical receive (VV) polarizations, and the cross-polarizations (XPOL) from the SMAP radar. RFI refers to the interference in measurements from other transmitters operating at frequencies in and adjacent to the SMAP L-band frequency.
Within the image, green indicates that Sigma0 observations are free of RFI and approved for science use, yellow indicates that caution should be used with the Sigma0 observations as RFI was detected but mitigated, and red indicates that Sigma0 observations are flagged as bad due to RFI.
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 Radar Global Daily 3 km EASE-Grid Soil Moisture
Data fields: sigma0_qual_flag_hh, sigma0_qual_flag_vv, sigma0_qual_flag_xpol