Data Announcements

New data sets released: SMAPVEX19-21 Massachusetts and Millbrook Temporary Soil Moisture Network

17 September 2020

The SMAPVEX19-21 Massachusetts and Millbrook Temporary Soil Moisture Network, Version 1 data sets, are now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). These data sets contain soil moisture sensor, soil temperature and air temperature measurements recorded by 25 temporary stations in both Massachusetts (MA) and Millbrook (MB) experiment locations during SMAPVEX19-21.

These data sets are available as part of an early release. Minimal documentation is currently available. An increased Level of Service and more detailed documentation will be available in the future. The NSIDC DAAC provides access to these data sets and documentation from the following locations:

SMAPVEX19-21 Massachusetts Temporary Soil Moisture Network, Version 1
Data set DOI: https://doi.org/10.5067/3LXL78PSKVXQ

SMAPVEX19-21 Millbrook Temporary Soil Moisture Network, Version 1
Data set DOI: https://doi.org/10.5067/NXNJWN9933UI

New data product updates: New versions of SMAP Level-1, -2, -3, and -4 data products now available at NSIDC

1 September 2020

The SMAP Project performs annual reprocessing of all its science data products based on improvements in the algorithms and supporting information. As part of this routine reprocessing, the SMAP Science Data System (SDS) has now released new versions of Level-1, -2, -3, and -4 data products, accessible through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). Several improvements were made to both standard and enhanced SMAP data products, including the following highlights:

Level-1 Brightness Temperatures: Applied an enhanced calibration methodology to the brightness temperatures, which improves absolute radiometric calibration and reduces the biases between ascending and descending passes. The impact on soil moisture products is small, but will enhance the use of SMAP Level-1 data for other applications, such as sea surface salinity and winds.
Level-2 and -3 Soil Moisture: Improved the soil moisture geophysical retrieval algorithm ancillary data inputs such as a new high-resolution soil database. Also updated the products to use the land surface temperature from the upgraded NASA GMAO model. The Dual Channel Algorithm (DCA) now has comparable performance as the baseline Single Channel Algorithm-Vertical polarization (SCA-V) and additionally provides retrievals of Vegetation Optical Depth (VOD). Added both optional soil moisture algorithms (Single Channel Algorithm-Horizontal polarization and DCA) to the Level-3 daily composite product files.
Level-3 Freeze/Thaw: Adjusted the normalized polarization ratio (NPR) and V-polarization threshold parameters per the Level-1 brightness temperature recalibration. Also improved the false-flag mitigation.
Level-4 Soil Moisture and Carbon: Updated the algorithms per the Level-1 brightness temperature recalibration and revised underpinning models.

The NSIDC DAAC provides access to these data sets and documentation from https://nsidc.org/data/smap/smap-data.html.

User Notice: Upcoming changes to SMAP Science Products

18 June 2020

The SMAP Level-1, -2, -3, and -4 data sets from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) will be updated in summer 2020 as part of a scheduled annual reprocessing campaign. Several improvements will be implemented to these data sets, both standard and enhanced, and include the following highlights:

Improved calibration methodology will be applied to the SMAP Level-1 radiometer brightness temperatures based on the internal instrument noise diode, deep-space measurements during monthly Cold Sky Maneuvers, stable open-ocean targets, and antenna system signal losses. The Level-2, -3 and -4 algorithms will be updated to use the new Level-1 observations.
Soil temperatures from the NASA Global Modeling and Assimilation Office (GMAO) will be used to estimate the soil microwave emission temperature needed to produce the SMAP Level-2 and -3 soil moisture estimates. GMAO transitioned to using an improved land surface model in early 2020, which required adjustments of the procedure used to estimate soil microwave emission temperatures from the GMAO soil temperature data.
Data quality flags will be updated and corrected where faulty.
Improvements will be applied to the Dual Channel Algorithm (DCA). This algorithm, which was first introduced last year as the Modified “DCA” (MDCA) in the Level-2 data sets as “option 3” algorithm, produces simultaneous estimates of soil moisture and vegetation optical depth.
Improved estimates of soil clay fraction and bulk density will be used to produce Level-2 and -3 soil moisture estimates. The new soil texture database avoids artifacts of political boundaries and watershed/geologic delineations that existed in the older composite data set.

As is done for each version update, each data set will be accompanied by Assessment Reports that provide performance metrics for the improved algorithms over a longer time period (2015-2020) than used in computing previous performance metrics.

Access to SMAP data sets and related documentation can be found at https://nsidc.org/data/smap/smap-data.html.

User Notice: SMAP data at NSIDC DAAC impacted by ancillary data input change

30 January 2020

SMAP data sets, accessible through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), are impacted by the following change. As of Thursday, 30 January 2020, NASA Goddard Space Flight Center’s Global Modeling and Assimilation Office has implemented an upgrade to the GEOS Forward Processing (FP) system, which provides ancillary data used in generating SMAP data products. In particular, the GEOS FP soil temperature values used in the SMAP Level-2 and -3 soil moisture retrieval algorithm are somewhat different after the system upgrade, and these differences will propagate into SMAP soil moisture retrievals going forward. Changes in other GEOS FP near-surface fields that are used in SMAP processing may also result in minor changes in SMAP Level-1 brightness temperatures, Level-3 freeze-thaw products, and Level-4 soil moisture and carbon products. The SMAP Project Team has begun an assessment of the impact of the GEOS FP upgrade on the SMAP data products and will communicate the results of the assessment as soon as possible to SMAP users.

Access to the SMAP data page at the NSIDC DAAC: https://nsidc.org/data/smap

Data set updates: Customizable SMAP data available as a subscription from the NSIDC DAAC

12 November 2019

The majority of SMAP data sets, accessible through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), are now available as customizable data subscriptions. Data subscriptions automatically deliver new data as they become available; deliveries can be made on an hourly, daily, weekly, or monthly basis, depending on your preference. This new service also allows you to apply customization options to your order, including reformatting, reprojecting, and spatial and parameter subsetting. For more information on setting up the subscription, please visit https://nsidc.org/daac/subscriptions.html.

For further details on SMAP data sets, including data access, please visit: https://nsidc.org/data/smap/

Application data update: Newest NSIDC DAAC SMAP data set versions available in AppEEARS

11 November 2019

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 3
DOI: https://doi.org/10.5067/T90W6VRLCBHI

SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 6
DOI: https://doi.org/10.5067/EVYDQ32FNWTH

Data set update: SMAP/In Situ Core Validation Site Land Surface Parameters Match-Up Data

8 October 2019

The SMAP/In Situ Core Validation Site Land Surface Parameters Match-Up Data, Version 1 data set, accessible through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), has been updated to include the most recent versions of Level-2 SMAP radiometer soil moisture products. This data set is matched with in-situ based soil moisture estimates from core validation sites and provides performance assessments of various SMAP soil moisture products.

Data set DOI: https://doi.org/10.5067/DXAVIXLY18KM

Level of service update: SMAP Radiometer Twice-Daily rSIR-Enhanced EASE-Grid 2.0 Brightness Temperatures

16 September 2019

The SMAP Radiometer Twice-Daily rSIR-Enhanced EASE-Grid 2.0 Brightness Temperatures, Version 1 data set, accessible through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), has been updated from a basic to a standard level of service. Please see our Adding clarity to NSIDC data support with new Level of Service (LoS) model article more information.

Data set DOI: https://doi.org/10.5067/QZ3WJNOUZLFK

New data set updates: SMAP Level-2 and Level-3 standard and enhanced radiometer soil moisture data sets

15 August 2019

The SMAP Level-2 and Level-3 standard and enhanced radiometer soil moisture data sets, accessible through the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), have been updated. The optional Dual Channel Algorithm (DCA) in the Level-2 products has been replaced by the Modified Dual Channel Algorithm (MCDA). The baseline algorithm (SCA-V) remains unchanged for both Level-2 and Level-3 products. Other primary changes include:

Level-2: the following data fields were removed: soil_moisture_option4, vegetation_opacity_option4, retrieval_qual_flag_option4, soil_moisture_option5, vegetation_opacity_option5, retrieval_qual_flag_option5.
Level-2: the following data fields were added: albedo_option3, roughness_coefficient_option3, bulk_density, clay_fraction.
Level-3: the following data fields were added: bulk_density, clay_fraction, bulk_density_pm, clay_fraction_pm.

The NSIDC DAAC provides access to documentation and these data sets from the following locations:

SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 6
Data set DOI: https://doi.org/10.5067/R50VUC07OM4W

SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 3
Data set DOI: https://doi.org/10.5067/017XZSKMLTT2

SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 6
Data set DOI: https://doi.org/10.5067/EVYDQ32FNWTH

SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 3
Data set DOI: https://doi.org/10.5067/T90W6VRLCBHI

Early data set release: SMAP Radiometer Twice-Daily rSIR-Enhanced EASE-Grid 2.0 Brightness Temperatures

31 July 2019

The SMAP Radiometer Twice-Daily rSIR-Enhanced EASE-Grid 2.0 Brightness Temperatures, Version 1 data set is now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). This data set contains twice-daily brightness temperature data derived from the SMAP radiometer and applies the same Scatterometer Image Reconstruction (SIR) technique used to derive brightness temperatures from the SMMR, AMSR-E, and SSM/I-SSMIS sensors. Data are available on the Northern Hemisphere, Southern Hemisphere, and Global EASE-Grid 2.0 projections, and on 3 km, 3.125 km, 9 km, 25 km, and 36 km resolution grids. This data set is available as part of an early release. Minimal documentation is currently available. An increased Level of Service and more detailed documentation will be available in the future.

Data set DOI: https://doi.org/10.5067/QZ3WJNOUZLFK

Update: SMAP in Science Mode

29 July 2019

The SMAP satellite returned to science mode and resumed collecting science data on 23 July 2019 at 22:28 UTC. These data are now available.

The SMAP science team has completed a preliminary data assessment and flagged the first ~25 seconds for quality concerns, as described in this advisory note. A more detailed quality assessment and a description of what caused the SMAP outage will be provided at a later date. NSIDC will continue to post updates as we learn more.

Update: SMAP in Science Mode

24 July 2019

The SMAP satellite returned to science mode and resumed collecting science data on 23 July 2019 at 22:28 UTC. However, data collected and processed after 23 July 2019 will not be available until the SMAP science team completes a data quality assessment. NSIDC will continue to provide updates as we gain a better understanding of data availability.

Update: SMAP in Safe Mode

8 July 2019

On the evening of 19 June 2019, SMAP went into safe mode and data collection was disrupted. SMAP is currently in standby mode. The task team is in communication with the satellite and working to restore normal operations. On 02 July 2019 the Non-volatile Memory (NVM) Parameter Management (NPM) backup partition was successfully recovered. The attempt to recover additional partitions will continue while SMAP is in standby mode.

NSIDC will continue to provide updates as we learn more information and gain a better understanding of the timeframe for resuming data collection.

Update: SMAP in Safe Mode

27 June 2019

On the evening of 19 June 2019, SMAP went into safe mode and data collection was disrupted. A task team has made progress in communicating with the satellite and diagnosing the malfunction. While they continue to work to return SMAP to normal operations, all instruments remain off. Currently, SMAP has been returned to standby mode with nominal nadir pointing and spinning antenna. Data collection has not restarted. A timeline for when SMAP may resume normal operations has not been provided, but may be on the order of several weeks.

While SMAP remains in standby mode, generation of the model-based Level-4 products will continue, but the Level-4 data will not be informed by contemporaneous SMAP observations.

NSIDC will continue to provide updates as we learn more information and gain a better understanding of the timeframe for resuming data collection.

SMAP in Safe Mode

24 June 2019

On the evening of 19 June 2019, the SMAP satellite went into safe mode. Subsystems are investigating the cause and possible solutions. In the meantime, all instruments are shutdown and there is no science data collection.
While SMAP remains in safe mode, generation of the model-based Level-4 product will continue, but the Level-4 data will not be informed by contemporaneous SMAP observations.
As NSIDC gets updates, we will post more details on the state of the spacecraft and data for all product levels.

User notice: Upcoming changes to SMAP Level-2 and Level-3 radiometer soil moisture products

23 April 2019

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

26 March 2019

SMAP ancillary data sets are now available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). These data sets are used to create SMAP Level-1, -2, -3, and -4 products and are made available as part of NSIDC DAAC’s mandate to preserve all SMAP data and related information for future research. Several of these ancillary data sets are produced by external organizations, such as NOAA, the NASA Global Modeling and Assimilation Office (GMAO), and NASA Land Data Assimilation Systems (LDAS). SMAP Ancillary Data web page: https://nsidc.org/data/smap/smap-ancillary-products

Application data update: Newest NSIDC DAAC SMAP data set versions available in AppEEARS

25 February 2019

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

29 January 2019

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

6 December 2018

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

10 October 2018

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

6 September 2018

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

18 June 2018

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

14 June 2018

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

6 June 2018

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

9 April 2018

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

19 March 2018

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

23 February 2018

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

2 February 2018

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

2 November 2017

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

11 September 2017

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

17 July 2017

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

21 June 2017

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

16 February 2017

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 Error

15 February 2017

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/E51BSP6V3KP7

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

2 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

31 January 2017

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

19 December 2016

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

22 September 2016

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

21 June 2016

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: https://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): https://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

1 June 2016

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 the 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

1 June 2016

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 the 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

2 May 2016