SMAP Enhanced L3 Radiometer Global and Polar Grid Daily 9 km EASE-Grid Soil Moisture, Version 6
Data set id:
SPL3SMP_E
DOI: 10.5067/M20OXIZHY3RJ
This is the most recent version of these data.
Version Summary
Version Summary
Changes to this version include:
• An improved processing methodology was applied to the input enhanced Level-2 radiometer brightness temperatures.
• The data algorithms, structure, content, or processor code are otherwise unchanged from the previous version.
For the full major and minor version history, go to https://nsidc.org/data/smap/version-history
• An improved processing methodology was applied to the input enhanced Level-2 radiometer brightness temperatures.
• The data algorithms, structure, content, or processor code are otherwise unchanged from the previous version.
For the full major and minor version history, go to https://nsidc.org/data/smap/version-history
Overview
This enhanced Level-3 (L3) soil moisture product provides a composite of daily estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer. This product is a daily composite of SMAP Level-2 (L2) soil moisture which is derived from SMAP Level-1C (L1C) interpolated brightness temperatures. Backus-Gilbert optimal interpolation techniques are used to extract information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) in a global cylindrical projection. As of 2021, the data are also posted to the Northern Hemisphere EASE-Grid 2.0, an azimuthal equal-area projection.
Parameter(s):
BRIGHTNESS TEMPERATURESURFACE SOIL MOISTURE
Platform(s):
SMAP
Sensor(s):
SMAP L-BAND RADIOMETER
Data Format(s):
HDF5
Temporal Coverage:
31 March 2015 to present
Temporal Resolution:
- 1 day
Spatial Resolution:
- 9 km
- 9 km
Spatial Reference System(s):
WGS 84 / NSIDC EASE-Grid 2.0 North
EPSG:6931
WGS 84 / NSIDC EASE-Grid 2.0 Global
EPSG:6933
Spatial Coverage:
N:
90
S:
-85.044
E:
180
W:
-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
Data Access & Tools
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Documentation
Help Articles
General Questions & FAQs
There is considerable overlap of the SMAP radiometer footprints, or Instantaneous Fields of View (IFOVs), which are defined by the contours where the sensitivity of the antenna has fallen by 3db from its maximum.
OPeNDAP, the Open-source Project for a Network Data Access Protocol, is a NASA community standard DAP that provides a simple way for researchers to access and work with data over the internet.
SMAP data files contain rich quality information that can be useful for many data users. The retrieval quality flag and surface flag bit values and interpretations are documented in the respective product Data Fields pages of the user guides for these data products
The following table describes both the required and actual latencies for the different SMAP radiometer data sets. Latency is defined as the time (# days, hh:mm:ss) from data acquisition to product generation.
This short article describes the customization services available for SMAP data using Earthdata Search.
While the standard SMAP Level-2 and -3 radiometer soil moisture products contain landcover_class and landcover_class_fraction in the data files, the enhanced soil moisture products do not.
How to Articles
Many NSIDC DAAC data sets can be accessed using the NSIDC DAAC's Data Access Tool. This tool provides the ability to search and filter data with spatial and temporal constraints using a map-based interface.Users have the option to
Harmony API Quickstart Guide: Customizing NASA NSIDC DAAC data in Earthdata Cloud
To convert HDF5 files into binary format you will need to use the h5dump utility, which is part of the HDF5 distribution available from the HDF Group. How you install HDF5 depends on your operating system.
This step-by-step tutorial demonstrates how to access MODIS and SMAP data using the Application for Extracting and Exploring Analysis Ready Samples (AppEEARS). AppEEARS allows users to access, explore, and download point and area data with spatial, temporal, and parameter subsets.
The following are instructions on how to import and geolocate SMAP Level-3 Radiometer Soil Moisture HDF5 data in ENVI.
Testing notes
Software: ENVI
Software version: 5.3
Platform: Windows 7
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All data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is directly accessible through our HTTPS file system using Wget or curl. This article provides basic command line instructions for accessing data using this method.
This article highlights the NSIDC DAAC data sets available with customization options and outlines a workflow for searching, ordering, and customizing data in NASA Earthdata Search. This approach is ideal for users who want to download data to their local machine.
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