Scientists
Research Grants
Scientific Publications
Informatics Research
NSIDC Scientific Expeditions
Scientists blog from Antarctica and provide a glimpse of what it's like to do research in the field. 
What's hot in the news around climate and sea ice and what are scientists talking about now? 
Data Announcements
User notice: Upcoming changes to SMAP Level-2 and Level-3 radiometer soil moisture products
The SMAP Level-2 and Level-3 standard and enhanced radiometer soil moisture products from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) are being updated in summer 2019. The Level-2 updates will introduce an improved version of the existing Dual Channel Algorithm, DCA (option 3). The new version, known as M-DCA, achieves better retrieval performance by modeling the mixing of vertically and horizontally polarized brightness temperature channels and using new estimates of single-scattering albedo and roughness coefficients. M-DCA (option 3) will supersede optional algorithms MPRA (option 4) and E-DCA (option 5), so the following data fields will be removed from the SMAP Level-2 standard and enhanced radiometer soil moisture products:
soil_moisture_option4
vegetation_opacity_option4
retrieval_qual_flag_option4
soil_moisture_option5
vegetation_opacity_option5
retrieval_qual_flag_option5
In addition, a clay fraction field and a bulk density field will be added to both the Level-2 and Level-3 products. The baseline retrieval algorithm remains SCA-V, which is unchanged from the previous release.
Access to each data set and related documentation can be found at:
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 5
DOI: https://doi.org/10.5067/SODMLCE6LGLL
SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 2
DOI: https://doi.org/10.5067/K4A1SNL5DLON
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 5
DOI: https://doi.org/10.5067/ZX7YX2Y2LHEB
SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 2
DOI: https://doi.org/10.5067/RFKIZ5QY5ABN
New data set release: SMAP Ancillary Data
Application data update: Newest NSIDC DAAC SMAP data set versions available in AppEEARS
The Application for Extracting and Exploring Analysis Ready Samples (AppEEARS) now includes the newest versions of select Soil Moisture Active Passive (SMAP) data sets from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). AppEEARS offers a simple and efficient way to subset SMAP data sets using spatial, temporal, and layer parameters for both point and area samples. A step-by-step tutorial for accessing SMAP data in AppEEARS is available.
Updates and information about each SMAP data set are described in more detail on the individual data set web pages linked below.
SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 2
DOI: https://doi.org/10.5067/RFKIZ5QY5ABN
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 5
DOI: https://doi.org/10.5067/ZX7YX2Y2LHEB
SMAP L3 Radiometer Global and Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State, Version 2
DOI: https://doi.org/10.5067/YN94K53QM061
SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, Version 4
DOI: https://doi.org/10.5067/9831N0JGVAF6
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data, Version 4
DOI: https://doi.org/10.5067/KPJNN2GI1DQR
New data set release: SMAPVEX16 Iowa and Manitoba data now available at NSIDC DAAC
SMAP validation data collected during the SMAPVEX16 Iowa (28 May 2016 to 16 August 2016) and SMAPVEX16 Manitoba (8 June 2016 to 22 July 2016) campaigns are now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). These data sets are derived from permanent in situ soil station measurements and observations by the Passive Active L-band System (PALS) microwave aircraft instrument. These data contain soil characteristics including volumetric soil moisture, vertically and horizontally polarized brightness temperature, effective soil temperature, effective vegetation temperature, vegetation water content, land cover classification, sand and clay fraction, and volumetric soil moisture uncertainty estimates.
SMAPVEX16 Iowa PALS Brightness Temperature and Soil Moisture Data, Version 1
DOI: https://doi.org/10.5067/0DJCHZKY1NVO
SMAPVEX16 Manitoba PALS Brightness Temperature and Soil Moisture Data, Version 1
DOI: https://doi.org/10.5067/WM5FXV7WPQ6F
Data set update: SMAP/In Situ Core Validation Site Land Surface Parameters Match-Up Data, Version 1
The SMAP/In Situ Core Validation Site Land Surface Parameters Match-Up Data, Version 1 data set has been updated from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). SMAP soil moisture data products are matched with in situ-based soil moisture estimates from core validation sites to produce this data set. These data provide performance assessments of various SMAP soil moisture products.
In this update, match-up data for SPL2SMP, Version 5 and SPL2SMP_E, Version 2 for the time period of 4/1/2015-04/01/2018 are provided.
Data set DOI: https://doi.org/10.5067/DXAVIXLY18KM
Level of service update: Soil Moisture Active Passive (SMAP) Validation Experiment 2016 Manitoba (SMAPVEX16), Version 1
The Soil Moisture Active Passive (SMAP) Validation Experiment 2016 Manitoba (SMAPVEX16), Version 1 data sets have been updated from a basic to a standard level of service at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). Please see our Adding clarity to NSIDC data support with new Level of Service (LoS) model article for more information.
These twelve data sets are designed to calibrate and increase the accuracy of NASA’s SMAP products. In situ and aircraft data were collected between May and July 2016 in the Carman/Elk region of Manitoba, Canada.
SMAPVEX16 Manitoba Core-Based In Situ Soil Moisture Data, Version 1
DOI: https://doi.org/10.5067/D4YA3124Y3BR
SMAPVEX16 Manitoba CropScan Data, Version 1
DOI: https://doi.org/10.5067/Y4W64RE5RWBF
SMAPVEX16 Manitoba In Situ Vegetation Data, Version 1
DOI: https://doi.org/10.5067/PP14EED9ZOE2
SMAPVEX16 Manitoba Land Cover Classification Map, Version 1
DOI: https://doi.org/10.5067/2JBTORD9BCBN
SMAPVEX16 Manitoba Leaf Area Index, Version 1
DOI: https://doi.org/10.5067/RY8S17GF8ZUH
SMAPVEX16 Manitoba Meteorological Data, Version 1
DOI: https://doi.org/10.5067/DLUBALJUPAWP
SMAPVEX16 Manitoba Probe-Based In Situ Soil Moisture Data, Version 1
DOI: https://doi.org/10.5067/1U1H8BGW6GDM
SMAPVEX16 Manitoba Radiometer Brightness Temperature Data, Version 1
DOI: https://doi.org/10.5067/7IJ1A8AGJRSL
SMAPVEX16 Manitoba Soil Texture Data, Version 1
DOI: https://doi.org/10.5067/A05VHIXID3FN
SMAPVEX16 Manitoba Soils Geodatabase, Version 1
DOI: https://doi.org/10.5067/OLKTT40AC6OL
SMAPVEX16 Manitoba Station Soil Moisture Data, Version 1
DOI: https://doi.org/10.5067/GMMWKUUCYYIR
SMAPVEX16 Manitoba Surface Roughness Data, Version 1
DOI: https://doi.org/10.5067/C18GQDVVRHOY
Data set update: Reprocessing is complete for SMAP levels 1-4 data
The SMAP Data System (SDS) has finished reprocessing the new versions of selected SMAP levels 1-4 data sets. The entire temporal coverage is now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) for each of the following data sets:
SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures, Version 4
DOI: https://doi.org/10.5067/VA6W2M0JTK2N
SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures, Version 4
DOI: https://doi.org/10.5067/ZVILG0PS6CTI
SMAP Enhanced L1C Radiometer Half-Orbit 9 km EASE-Grid Brightness Temperatures,
Version 2
DOI: https://doi.org/10.5067/0DGGEWUC6MLY
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 5
DOI: https://doi.org/10.5067/SODMLCE6LGLL
SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 2
DOI: https://doi.org/10.5067/K4A1SNL5DLON
SMAP L3 Radiometer Global and Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State, Version 2
DOI: https://doi.org/10.5067/YN94K53QM061
SMAP Enhanced L3 Radiometer Global and Northern Hemisphere Daily 9 km EASE-Grid Freeze/Thaw State, Version 2
DOI: https://doi.org/10.5067/1M7OJC7R7VKI
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 5
DOI: https://doi.org/10.5067/ZX7YX2Y2LHEB
SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 2
DOI: https://doi.org/10.5067/RFKIZ5QY5ABN
SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, Version 4
DOI: https://doi.org/10.5067/9831N0JGVAF6
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update, Version 4
DOI: https://doi.org/10.5067/60HB8VIP2T8W
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data, Version 4
DOI: https://doi.org/10.5067/KPJNN2GI1DQR
SMAP L4 Global 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants, Version 4
DOI: https://doi.org/10.5067/KGLC3UH4TMAQ
Update for SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture
The SMAP Science Data System (SDS) has updated the SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture data product at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). This data set uses SMAP L-band brightness temperatures and Copernicus Sentinel-1 C-band backscatter coefficients to derive soil moisture data, which are then resampled to an Earth-fixed, cylindrical 3 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0).
Primary changes include:
- Fewer spurious sigma0 values caused by small man-made structures
- Replaced the previous 3 km resolution urban fraction map with a new 1 km resolution map.
Data Set DOI: https://doi.org/10.5067/KE1CSVXMI95Y
NASA SMAP Level-4 Version Updates
The SMAP Science Data System (SDS) has released updated NASA SMAP data products at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). The following NASA SMAP Level 4 data sets have been updated:
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update, Version 4 (SPL4SMAU)
Data Set DOI: https://dx.doi.org/10.5067/60HB8VIP2T8W
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data, Version 4 (SPL4SMGP)
Data Set DOI: https://dx.doi.org/10.5067/KPJNN2GI1DQR
SMAP L4 Global 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constraints, Version 4 (SPL4SMLM)
Data Set DOI: https://dx.doi.org/10.5067/KGLC3UH4TMAQ
SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, Version 4 (SPL4CMDL)
Data Set DOI: https://dx.doi.org/10.5067/9831N0JGVAF6
Primary changes include:
- SPL4SMAU, SPL4SMGP, & SPL4SMLM: Land surface modeling system improvements. In addition, data is more CF compliant with the addition of x and y coordinate variables as well as an EASE Grid 2.0 projection mapping variable, which improves interoperability with ArcGIS, QGIS, OPeNDAP, and programmatic access.
- SPL4CMDL: Improvements in model inputs and ancillary files resulting in better RMSE, especially for drier sites.
New Versions of SMAP Products Available
The SMAP Science Data System (SDS) has released updated NASA SMAP data products at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). The following NASA SMAP Levels 1-3 data have been updated:
SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures, Version 4 (SPL1BTB)
Data Set DOI: https://dx.doi.org/10.5067/VA6W2M0JTK2N
SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures, Version 4 (SPL1CTB)
Data Set DOI: https://dx.doi.org/10.5067/ZVILG0PS6CTI
SMAP Enhanced L1C Radiometer Half-Orbit 9 km EASE-Grid Brightness Temperatures, Version 2 (SPL1CTB_E)
Data Set DOI: https://dx.doi.org/10.5067/0DGGEWUC6MLY
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 5 (SPL2SMP)
Data Set DOI: https://dx.doi.org/10.5067/SODMLCE6LGLL
SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 2 (SPL2SMP_E)
Data Set DOI: https://dx.doi.org/10.5067/K4A1SNL5DLON
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 5 (SPL3SMP)
Data Set DOI: https://dx.doi.org/10.5067/ZX7YX2Y2LHEB
SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 2 (SPL3SMP_E)
Data Set DOI: https://dx.doi.org/10.5067/RFKIZ5QY5ABN
SMAP L3 Radiometer Global and Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State, Version 2 (SPL3FTP)
Data Set DOI: https://dx.doi.org/10.5067/YN94K53QM061
SMAP Enhanced L3 Radiometer Global and Northern Hemisphere Daily 9 km EASE-Grid Freeze/Thaw State, Version 2 (SPL3FTP_E)
Data Set DOI: https://dx.doi.org/10.5067/1M7OJC7R7VKI
Primary changes include:
- Level-1 Brightness Temperatures: Added procedure to correct brightness temperatures for water/land contamination near coastlines
- Level-2 and -3 Soil Moisture: Improved depth correction for effective soil temperature
- Level-3 Freeze/Thaw: Implemented supplementary single-channel V-pol (SCV) algorithm for areas of lower latitudes, extending the spatial coverage to global
SMAP Products Now Available via AppEEARS
The Application for Extracting and Exploring Analysis Ready Samples (AppEEARS) now includes Soil Moisture Active Passive (SMAP) data products distributed by the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
AppEEARS offers a simple and efficient way to subset SMAP data sets using spatial, temporal, and layer parameters for both point and area samples. In addition, a step-by-step tutorial for accessing SMAP data in AppEEARS is available for the following five products:
Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture (SPL3SMP_E), Version 1
DOI: https://doi.org/10.5067/ZRO7EXJ8O3XI
L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture (SPL3SMP), Version 4
DOI: https://doi.org/10.5067/OBBHQ5W22HME
L3 Radiometer Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State (SPL3FTP), Version 1
DOI: https://doi.org/10.5067/RDEJQEETCNWV
L4 Global Daily 9 km Carbon Net Ecosystem Exchange (SPL4CMDL), Version 3
DOI: https://doi.org/10.5067/O4HAQJEWWUU8
L4 Global 9 km Surface and Root Zone Soil Moisture Geophysical Data (SPL4SMGP), Version 3
DOI: https://doi.org/10.5067/B59DT1D5UMB4
Probe-Based Soil Moisture Data Available for the SMAPVEX15 Campaign
Field data from the Soil Moisture Active Passive Validation Experiment 2015 (SMAPVEX15) validation campaign are now available at the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
The new data set contains in situ gravimetric and volumetric soil moisture, bulk density, and soil temperature measurements. Visit the product page for details:
SMAPVEX15 Probe-Based In Situ Soil Moisture Data, Version 1
DOI: https://doi.org/10.5067/QTDS3ZGQNM95
To access all SMAP validation data and documentation, see the SMAP Validation Data web page.
Early Release of SMAPVEX16 Manitoba Validation Data
A variety of field data from the Soil Moisture Active Passive Validation Experiment 2016 Manitoba (SMAPVEX16 Manitoba) validation campaign is now available at the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
Though minimal information is currently available, these data sets are available as part of an early release.Visit the product pages for details:
SMAPVEX16 Manitoba CropScan Data, Version 1
DOI: https://dx.doi.org/10.5067/Y4W64RE5RWBF
SMAPVEX16 Manitoba Leaf Area Index, Version 1
DOI: https://dx.doi.org/10.5067/RY8S17GF8ZUH
SMAPVEX16 Manitoba Land Cover Classification Map, Version 1
DOI: https://dx.doi.org/10.5067/2JBTORD9BCBN
SMAPVEX16 Manitoba Meteorological Data, Version 1
DOI: https://dx.doi.org/10.5067/DLUBALJUPAWP
SMAPVEX16 Manitoba Probe-Based In Situ Soil Moisture Data, Version 1
DOI: https://dx.doi.org/10.5067/1U1H8BGW6GDM
SMAPVEX16 Manitoba Surface Roughness Data, Version 1
DOI: https://dx.doi.org/10.5067/C18GQDVVRHOY
SMAPVEX16 Manitoba Station Soil Moisture Data, Version 1
DOI: https://dx.doi.org/10.5067/GMMWKUUCYYIR
SMAPVEX16 Manitoba Soil Texture Data, Version 1
DOI: https://dx.doi.org/10.5067/A05VHIXID3FN
SMAPVEX16 Manitoba Radiometer Brightness Temperature Data, Version 1
DOI: https://dx.doi.org/10.5067/7IJ1A8AGJRSL
SMAPVEX16 Manitoba Soils Geodatabase, Version 1
DOI: https://dx.doi.org/10.5067/OLKTT40AC6OL
SMAPVEX16 Manitoba In Situ Vegetation Data, Version 1
DOI: https://dx.doi.org/10.5067/PP14EED9ZOE2
To access all SMAP validation data and documentation, see the SMAP Validation Data Web page.
Early Release of SMAPVEX16 Validation Data
Field data from the Soil Moisture Active Passive Validation Experiment 2016 Manitoba (SMAPVEX16 Manitoba) validation campaign are now available at the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
The new data set, that contains in situ measurements of soil moisture and bulk density, is the first of many for the SMAPVEX16 Manitoba campaign. Though minimal information is presently available, the data set is available as an early release. Visit the product page for details:
SMAPVEX16 Manitoba Core-Based In Situ Soil Moisture Data, Version 1
DOI: http://dx.doi.org/10.5067/D4YA3124Y3BR
To access all SMAP validation data and documentation, see the SMAP Validation Data Web page.
High-resolution SMAP/Sentinel-1 Soil Moisture Data Available
The beta version of the SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture data set is now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
L-band radiometer measurements from the SMAP satellite and C-band radar measurements from the European Space Agency (ESA) Copernicus Sentinel-1 satellite are combined to produce high-resolution soil moisture estimates for this product.
The SMAP Science Data System (SDS) began forward processing for the data on 27 October 2017. Data reprocessing from 01 April 2015 to 27 October 2017 will start in mid-November 2017. The data will be made available as they are processed, and registered users will be notified when reprocessing is complete.
These beta-quality data use preliminary algorithms that are still being validated and are therefore subject to uncertainties. The calibrated/validated release of this data set is expected to occur in Spring 2018.
Data set DOI: http://dx.doi.org/10.5067/9UWR1WTHW1WN
To access all SMAP data and documentation, visit the SMAP Data Web site.
First of SMAPVEX15 Validation Data Sets Now Available
Field data from the Soil Moisture Active Passive Validation Experiment 2015 (SMAPVEX15) validation campaign are now available at the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
The new data set is the first of many for the SMAPVEX15 campaign and contains brightness temperatures obtained by the Passive Active L-band System (PALS) aircraft instrument. Visit the product page for details:
SMAPVEX15 PALS Brightness Temperature Data, Version 1
Data set DOI: http://dx.doi.org/10.5067/50DIUMRHN5E1
To access all SMAP validation data and documentation, see the SMAP Validation Data Web page.
Updated SMAP Level-4 Products Available
SMAP Level-4 soil moisture and carbon data have been updated to Version 3 and are available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) via the following product pages:
SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data (SPL4SMGP), Version 3
Data set DOI: http://dx.doi.org/10.5067/B59DT1D5UMB4
SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update (SPL4SMAU), Version 3
Data set DOI: http://dx.doi.org/10.5067/20ULJH6EZKFJ
SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants (SPL4SMLM), Version 3
Data set DOI: http://dx.doi.org/10.5067/4IYTBSUKM57Q
SMAP L4 Global Daily 9 km Carbon Net Ecosystem Exchange (SPL4CMDL), Version 3
Data set DOI: http://dx.doi.org/10.5067/O4HAQJEWWUU8
Primary changes to SMAP Level-4 soil moisture data include:
- SMAP observations are now assimilated in Eastern Europe, the Middle East, and East Asia due to expanded coverage of the brightness temperature scaling parameters. The latter are based on two years of SMAP Version 3 brightness temperature observations where the SMOS climatology is unavailable due to RFI.
- An improved version of the model-only Nature Run (NRv4.1) simulation is used to derive the brightness temperature scaling parameters, the model soil moisture initial conditions, and the soil moisture climatology.
Primary changes to SMAP Level-4 carbon data include:
- Model now uses dynamic 8-day fPAR inputs obtained from the latest (Collection 6) MODIS fPAR record at 500 m resolution.
- Updated and recalibrated ancillary Biome Properties Look-Up Table (BPLUT) and re-initialized model initial global soil organic carbon (SOC) pools to reflect new MODIS Collection 6 fPAR inputs.
Replacement Files Available for SMAP Data Impacted by Atmospheric Correction Issue
An issue involving the atmospheric correction algorithm used to process SMAP Level-1B (L1B) brightness temperatures, as noted in the Select Data Files Impacted by SMAP L1B Processing Error data announcement, has been corrected as of 24 April 2017.
The SMAP Science Data System (SDS) has reprocessed all affected SMAP Level-1B (L1B), Level-1C (L1C), and Level-2 (L2) radiometer files that had previously been removed. These reprocessed files contain a Composite Release ID (CRID) number of R15060 in the file name. Users are advised to download the replacement data files at their earliest convenience.
Replacement Files Available for SMAP Data Impacted by Antenna Azimuth Issue
Due to a problem with the Antenna Azimuth file used to process the half-orbit 01966_A, the SMAP Science Data System (SDS) team has replaced the following files:
SMAP_L1B_TB_01966_A_20150614T231537_R14010_001.h5 (Regenerated 2017-02-11)
SMAP_L1C_TB_01966_A_20150614T231537_R14010_001.h5 (Regenerated 2017-02-14)
SMAP_L1C_TB_E_01966_A_20150614T231537_R14010_001.h5 (Regenerated 2017-02-14)
SMAP_L2_SM_P_E_01966_A_20150614T231537_R14010_001.h5 (Regenerated 2017-02-14)
SMAP_L2_SM_P_01966_A_20150614T231537_R14010_001.h5 (Regenerated 2017-02-16)
The SMAP SDS has corrected the Antenna Azimuth file and regenerated these half-orbits. Users are advised to download the replacement data files at their earliest convenience.
Select Data Files Impacted by SMAP L1B Processing Algorithm Error
Due to a problem involving the atmospheric correction algorithm used to process SMAP Level-1B (L1B) brightness temperatures, select half-orbit data files contain invalid brightness temperature values. The errors occur infrequently, about one half orbit per month, and affected files have been removed from the following data sets:
SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures (SPL1BTB), Version 3
Data Set DOI: http://dx.doi.org/10.5067/YV5VOWY5V446
SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures (SPL1CTB), Version 3
Data Set DOI: http://dx.doi.org/10.5067/Y9C3Q3060AZ5
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture (SPL2SMP), Version 4
Data Set DOI: http://dx.doi.org/10.5067/XPJTJT812XFY
The SMAP Science Data System (SDS) team is working to correct the issue in forward processing. Until that time, files will continue to be affected with a frequency of approximately one half orbit per month. NSIDC DAAC will continue to identify and remove all affected files. Files currently affected are documented in a missing files spreadsheet, which will be updated and posted to the following How To article approximately once per month.
Users of L1B brightness temperature data will be able to identify affected files by looking at the first element in tb_lat, tb_lon, or ta_filtered_3. If the element contains the fill value -9999.00, the brightness temperatures stored in tb_v and tb_h will be invalid.
Users of L1C brightness temperature and L2 soil moisture data will need to identify the affected files based on the filenames or orbit numbers documented in the missing files spreadsheet (see the corresponding How To article).
All deleted files will be replaced during the next reprocessing from the beginning of the SMAP mission. Registered users will be notified when reprocessing occurs.
NSIDC Polaris Search and Order being Retired 15 February 2017
THE NSIDC Polaris Search and Order tool will be retired on 15 February 2017. Please contact NSIDC User Services via email: nsidc@nsidc.org with questions.
Reprocessing Complete for Newly Released SMAP Radiometer Data
The SMAP Science Data System (SDS) has completed reprocessing of the latest release of SMAP radiometer data products. As a result, the following products are now available from 31 March 2015 to the present:
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture (SPL2SMP), Version 4
Data Set DOI: http://dx.doi.org/10.5067/XPJTJT812XFY
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture (SPL3SMP), Version 4
Data Set DOI: http://dx.doi.org/10.5067/OBBHQ5W22HME
SMAP Enhanced L1C Radiometer Half-Orbit 9 km EASE-Grid Brightness Temperatures (SPL1CTB_E), Version 1
Data Set DOI: http://dx.doi.org/10.5067/2C9O9KT6JAWS
SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture (SPL2SMP_E), Version 1
Data Set DOI: http://dx.doi.org/10.5067/CE0K6JS5WQMM
SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture (SPL3SMP_E), Version 1
Data Set DOI: http://dx.doi.org/10.5067/ZRO7EXJ8O3XI
SMAP L3 Radiometer Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State (SPL3FTP), Version 1
Data Set DOI: http://dx.doi.org/10.5067/RDEJQEETCNWV
SMAP Enhanced L3 Radiometer Northern Hemisphere Daily 9 km EASE-Grid Freeze/Thaw State (SPL3FTP_E), Version 1
Data Set DOI: http://dx.doi.org/10.5067/Z08PIR8RGVR2
New and Updated NASA SMAP Radiometer Products Now Available
The SMAP Science Data System (SDS) has released several new and updated NASA Soil Moisture Active Passive (SMAP) radiometer data products at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC).
The following products have been updated to Version 4:
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture (SPL2SMP)
Data Set DOI: http://dx.doi.org/10.5067/XPJTJT812XFY
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture (SPL3SMP)
Data Set DOI: http://dx.doi.org/10.5067/OBBHQ5W22HME
The primary change implemented in this version is the addition of data from the 6:00 p.m. ascending half-orbit passes, which provides increased spatial coverage.
In addition, the following products are new to the SMAP collection:
SMAP Enhanced L1C Radiometer Half-Orbit 9 km EASE-Grid Brightness Temperatures (SPL1CTB_E)
Data Set DOI: http://dx.doi.org/10.5067/2C9O9KT6JAWS
SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture (SPL2SMP_E)
Data Set DOI: http://dx.doi.org/10.5067/CE0K6JS5WQMM
SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture (SPL3SMP_E)
Data Set DOI: http://dx.doi.org/10.5067/ZRO7EXJ8O3XI
SMAP L3 Radiometer Northern Hemisphere Daily 36 km EASE-Grid Freeze/Thaw State (SPL3FTP)
Data Set DOI: http://dx.doi.org/10.5067/RDEJQEETCNWV
SMAP Enhanced L3 Radiometer Northern Hemisphere Daily 9 km EASE-Grid Freeze/Thaw State (SPL3FTP_E)
Data Set DOI: http://dx.doi.org/10.5067/Z08PIR8RGVR2
The new enhanced radiometer products (SPL1CTB_E, SPL2SMP_E, SPL3SMP_E, and SPL3FTP_E) obtain the maximum value from the SMAP radiometer by using Backus-Gilbert optimal interpolation techniques to provide data on a finer (9 km) grid posting than the standard 36 km.
The new radiometer freeze/thaw products (SPL3FTP and SPL3FTP_E) are daily composites of Northern Hemisphere freeze/thaw conditions retrieved by the SMAP radiometer.
As of 07 December 2016, the SMAP Science Data System (SDS) has begun forward processing all products listed above. Data reprocessing from the beginning of the SMAP mission to 07 December 2016 will begin in January 2017. Registered users will be notified when reprocessing is complete.
To access data, documentation, and tools, refer to the SMAP Web site at the NSIDC DAAC: http://nsidc.org/data/smap/
Select Files Removed from SMAP Data Sets
Due to a problem with the Antenna Scan Angle file used to process the half-orbit 08619_D, the SMAP Science Data System (SDS) has removed the following files:
SMAP_L1A_RADIOMETER_08619_D_20160911T214948_R13080_001.h5
SMAP_L1B_TB_08619_D_20160911T214948_R13080_001.h5
SMAP_L1C_TB_08619_D_20160911T214948_R13080_001.h5
SMAP_L2_SM_P_08619_D_20160911T214948_R13080_001.h5
In addition, the SMAP Level-3 Soil Moisture Radiometer composite file that contains the affected half-orbit scan has been regenerated without half-orbit 08619_D in order to replace the errant file. The new file is:
SMAP_L3_SM_P_20160911_R13080_002.h5
If you have questions, please contact our User Services Office via e-mail: nsidc@nsidc.org. We apologize for any inconvenience this may cause.
Reprocessing Complete for SMAP Data
The SMAP Science Data System (SDS) has completed reprocessing of the NASA SMAP Level-1B, -1C, -2, and -3 data products to Validated Version 3. Additionally, SMAP Level-4 products have been reprocessed to Validated Version 2.
During reprocessing, Level-1B, -1C, -2 and -3 data spanning the time period 19 November 2015 to 02 February 2016 were regenerated and replaced due to an issue with a spacecraft ancillary input file. The affected files end with R13080_001.h5. Users who currently have files within this date range may want to download the replacements, as portions of the right edge of the swath near 270° antenna azimuth were erroneously set to fill values.
Changes implemented in these versions are summarized on the SMAP Data Versions page: http://nsidc.org/data/smap/data_versions
To access data, documentation, and tools, visit the SMAP website at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC): http://nsidc.org/data/smap/
Note that SMAP Level-1 radar data and documentation are accessible through the NASA Alaska Satellite Facility Distributed Active Archive Center (ASF DAAC): https://www.asf.alaska.edu/smap/
File Removed from the SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures Data Set
The SMAP_L1B_TB_01966_A_20150614T231537_R13080_001.h5 file was removed from the SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures Data Set because of a problem with the Antenna Azimuth file used to process this half-orbit. The SMAP Science Data System (SDS) is working to correct the Antenna Azimuth file and regenerate these half-orbits. Once we receive the new file, we will let you know.
If you have any questions, please contact our User Services Office via e-mail: nsidc@nsidc.org. We apologize for any inconvenience this may cause you.
File Removed from the SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures Data Set
The SMAP_L1C_TB_01966_A_20150614T231537_R13080_001.h5 file was removed from the SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures Data Set because of a problem with the Antenna Azimuth file used to process this half-orbit. The SMAP Science Data System (SDS) is working to correct the Antenna Azimuth file and regenerate these half-orbits. Once we receive the new file, we will let you know.
If you have any questions, please contact our User Services Office via e-mail: nsidc@nsidc.org. We apologize for any inconvenience this may cause you.
New Versions of SMAP Products Available
We are pleased to announce that the SMAP Science Data System (SDS) has begun reprocessing of all data and forward processing of the radiometer data to Validated Version 3 for the Level-1B, -1C, -2, and -3 data products and Validated Version 2 for the Level-4 data products. Registered users will be notified when reprocessing is complete.
Changes implemented in these versions are summarized on the SMAP Data Versions page at the NSIDC DAAC: http://nsidc.org/data/smap/data_versions
To access data, documentation, and tools, please see the SMAP Web site at the NSIDC DAAC: http://nsidc.org/data/smap/
Reprocessing Complete for NASA SMAP L2 and L3 Radar and Combined Radar/Radiometer Data
The SMAP Science Data System (SDS) has completed reprocessing of NASA SMAP Level-2 and -3 radar and combined radar/radiometer data to Beta Version 2. The following data sets are now available for the full radar time series, 13 April 2015 to 07 July 2015, at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC):
SMAP L2 Radar Half-Orbit 3 km EASE-Grid Soil Moisture (SPL2SMA)
Data Set DOI: http://dx.doi.org/10.5067/6O6GPHUJ2QXM
SMAP L2 Radar/Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture (SPL2SMAP)
Data Set DOI: http://dx.doi.org/10.5067/LZIP2VM2GIA5
SMAP L3 Radar Global Daily 3 km EASE-Grid Soil Moisture (SPL3SMA)
Data Set DOI: http://dx.doi.org/10.5067/6QFA65R4RPOH
SMAP L3 Radar/Radiometer Global Daily 9 km EASE-Grid Soil Moisture (SPL3SMAP)
Data Set DOI: http://dx.doi.org/10.5067/F88YVH7CVNXS
SMAP L3 Radar Northern Hemisphere Daily 3 km EASE-Grid Freeze/Thaw State (SPL3FTA)
Data Set DOI: http://dx.doi.org/10.5067/GO4QPNEM0BKF
Reprocessing Complete for NASA SMAP Radiometer Data at NSIDC DAAC
The SMAP Science Data System (SDS) has completed reprocessing of NASA SMAP Level-1, -2, and -3 radiometer data products to Version 2. The following data sets are now available for the full radiometer time series, 31 March 2015 to present, at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC):
SMAP L1A Radiometer Time-Ordered Parsed Telemetry (SPL1AP)
Data Set DOI: http://dx.doi.org/10.5067/JGV8EY3FGAH1
SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures (SPL1BTB)
Data Set DOI: http://dx.doi.org/10.5067/VIQYQV0AJATI
SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures (SPL1CTB)
Data Set DOI: http://dx.doi.org/10.5067/Y9C3Q3060AZ5
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture (SPL2SMP)
Data Set DOI: http://dx.doi.org/10.5067/3Q9102MCFF72
SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture (SPL3SMP)
Data Set DOI: http://dx.doi.org/10.5067/7EW92T1NI4M4
Entire SMAP Radiometer and Radar Suite Now Available
We are pleased to announce that all data from the NASA Soil Moisture Active Passive (SMAP) mission are now available at the National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) and the NASA Alaska Satellite Facility Distributed Active Archive Center (ASF DAAC). The two NASA DAACs jointly manage SMAP science data on behalf of the NASA ESDIS Project.
SMAP combines coincident L-band radar and radiometer measurements to produce global, high-resolution soil moisture and freeze/thaw estimates. SMAP data available at the NSIDC DAAC include Level-1 through Level-4 radiometer data, Level-2 and Level-3 radar and combined radar/radiometer data, and Level-4 radiometer data. SMAP Level-1 radar data are available at the ASF DAAC.
Currently, Level-2 through Level-4 SMAP data are Beta-quality. Users should note that Beta-quality data use preliminary algorithms that are still being validated and are thus subject to uncertainties. Level-1 SMAP data have been processed to Validated. To access SMAP data and documentation, refer to the SMAP Data page.
SMAP Releases Level-2 and Level-3 Soil Moisture Data
The NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is pleased to announce the release of SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture and SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture data sets.
These Level-2 (L2) and Level-3 (L3) soil moisture products provide gridded estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) passive microwave radiometer.
SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 1 Beta
Data set DOI: http://dx.doi.org/10.5067/HF1KOE0Q85V7
SMAP L3 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 1 Beta
Data set DOI: http://dx.doi.org/10.5067/NTZW5L0XYP38
First Release of Instrument Data from the SMAP Mission
We are pleased to announce that the beta version of Level-1 radiometer data from NASA’s Soil Moisture Active Passive (SMAP) mission is now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). In addition, the beta version of Level-1 radar data is now available at the NASA Alaska Satellite Facility (ASF DAAC). SMAP combines coincident L-band radar and radiometer measurements to produce global, high-resolution soil moisture estimates.
As of 30 July 2015, the SMAP Science Data System (SDS) began forward processing Version 1 (beta) radiometer data, which will be made available at the NSIDC DAAC within 12 hours of satellite observation. Reprocessing of data from 31 March 2015 to 29 July 2015 to Version 1 has also begun and data will be made available as they are processed. This reprocessing is expected to be completed in the coming weeks, after which registered data users will receive an announcement.
The beta version (Version 1) of SMAP data sets available at the NSIDC DAAC include:
- SMAP L1A Radiometer Time-Ordered Parsed Telemetry
Data Set DOI: http://dx.doi.org/10.5067/3G0GFQR7OT5E - SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures
Data Set DOI: http://dx.doi.org/10.5067/1V33MVRRLCCT - SMAP L1C Radiometer Half-Orbit 36 km EASE-Grid Brightness Temperatures
Data Set DOI: http://dx.doi.org/10.5067/RP9DZ1CC6XNP
For Level-1 radar data, visit the ASF DAAC.
Data users should be aware that these data use preliminary algorithms that are still being validated and are thus subject to uncertainties. The validated release (Version 2) of all Level-1 data sets is expected to occur in the coming months, along with the beta release of the Level-2, -3, and -4 data sets.
New SMAPVEX12 Soil Texture Map Available
New field campaign data from the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) are now available at the NASA National Snow and Ice Data Center
Distributed Active Archive Center (NSIDC DAAC). The SMAPVEX12 Soil Texture Map incorporates soil texture classification data obtained from detailed soil surveys conducted near Winnipeg, Canada.
To access all currently available SMAPVEX12 data sets and documentation, visit the SMAP Validation Data Web page.
New SMAPVEX12 Data Available
New validation field campaign data from the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) are now available at the NASA National Snow and Ice Data Center
Distributed Active Archive Center (NSIDC DAAC), including:
- Core-Based In Situ Soil Moisture Data for Agricultural Area
- Core-Based Soil Texture Data
- In Situ Vegetation Data for Forest Area
To access all currently available SMAPVEX12 data sets and documentation, visit the SMAP Validation Data Web page.
New SMAPVEX12 Data Available at NSIDC
We are pleased to announce that new validation field campaign data from the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) are available at NSIDC.
The new SMAPVEX12 data sets include:
- UAVSAR Incidence-Angle Normalized Backscatter Data
- Vegetation Water Content Map
- Land Cover Classification Map
To access all currently available SMAPVEX12 data and documentation, visit the SMAP Validation Data Web page.
NSIDC Web Site and FTP Server Down for System Maintenance
From 4:30 p.m. Wednesday, June 04 until noon Friday, June 06 (USA Mountain Time), our Web site and FTP server will be unavailable due to system maintenance. We apologize for any inconvenience this may cause you.
NSIDC Releases Soil Moisture Active Passive (SMAP) Web Site
We are pleased to announce the release of the official NSIDC Soil Moisture Active Passive (SMAP) Web site. As the SMAP mission progresses, the SMAP Data Web site will provide one convenient location to access SMAP satellite and validation data, tools and services, data version history, news, published research, and other resources.
In addition, seven data sets are currently available from the SMAP Validation Experiment 2012 (SMAPVEX12). To access data and documentation from the SMAPVEX12 campaign, visit the SMAP Validation Data Web page.
