Name: SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 1
Creator: National Snow and Ice Data Center
Keywords: BRIGHTNESS TEMPERATURE,SOIL MOISTURE

SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 1

Data set id:

SPL2SMP_E

DOI: 10.5067/CE0K6JS5WQMM

Data Citation and Acknowledgment
As a condition of using these data, you must cite the use of this data set. Such a practice gives credit to data set producers and advances principles of transparency and reproducibility.

O'Neill, P. E., Chan, S., Njoku, E. G., Jackson, T. & Bindlish, R. (2016). SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture. (SPL2SMP_E, Version 1). [Data Set]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. https://doi.org/10.5067/CE0K6JS5WQMM. [describe subset used if applicable]. Date Accessed 09-23-2025.

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There is a more recent version of these data.
Version Summary

First public data release

Overview

This enhanced Level-2 (L2) soil moisture product provides estimates of global land surface conditions retrieved by the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. This product is derived from SMAP Level-1C (L1C) interpolated brightness temperatures. Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) in a global cylindrical projection.

Parameter(s):

BRIGHTNESS TEMPERATURE

SOIL MOISTURE

Platform(s):

SMAP Observatory

Sensor(s):

SMAP L-BAND RADIOMETER

Data Format(s):

HDF5

Temporal Coverage:

31 March 2015 to 4 June 2018

Temporal Resolution:

49 minute

Spatial Resolution:

9 km

9 km

Spatial Reference System(s):

Not Specified

Spatial Coverage:

N:
85.044
S:
-85.044
E:
180
W:
-180

Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

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Data Access & Tools

This data set has been retired. There is a more recent version of these data.

Documentation

Help Articles

General Questions & FAQs

How are the enhanced SMAP radiometer products generated and what are the benefits of using these products?

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.

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.

The NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) is migrating its primary data access from its legacy, on-premises archive to the NASA Earthdata Cloud.

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

Filter and order from a data set web page using the Data Access Tool

Many NSIDC DAAC data sets can be accessed using 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:

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.

The following are instructions on how to import and geolocate SMAP Level-1C HDF5 data in ENVI. Testing notes Software: ENVI Software version: 5.3 and above. If using version 5.3, service pack 5.3.1 is needed. Platform: Windows 7

NASA Earthdata Cloud Data Access Guide

The NASA Earthdata Cloud is the NASA cloud-based archive of Earth observations. It is hosted by Amazon Web Services (AWS). Learn how to find and access NSIDC DAAC data directly in the cloud.

Programmatic Data Access Guide

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.

NASA Worldview is a map interface that allows users to interactively browse imagery, create visualizations, and download the underlying data.

NASA's Global Imagery Browse Services (GIBS) provides up to date, full resolution imagery for selected NSIDC DAAC data sets.

Overview

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Documentation

ATBDs

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