SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update, Version 4
Data set id:
SPL4SMAU
DOI: 10.5067/60HB8VIP2T8W
There is a more recent version of these data.
Version Summary
Version Summary
Changes to this version include: Revisions to the land surface modeling system; Revisions to the parameters and parameterizations of the surface energy balance and the snow depletion curve; Analysis increments are no longer computed for the “catchment deficit” model prognostic variable in the Ensemble Kalman filter update step; Added x and y coordinate variables as well as an EASE-Grid 2.0 projection grid mapping variable; Minor bug fixes.
For the full major and minor version history, go to https://nsidc.org/data/smap/data_versions.
For the full major and minor version history, go to https://nsidc.org/data/smap/data_versions.
Overview
SMAP Level-4 (L4) surface and root zone soil moisture data are provided in three products:
* SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data (SPL4SMGP, DOI: 10.5067/KPJNN2GI1DQR)
* SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update (SPL4SMAU, DOI: 10.5067/60HB8VIP2T8W)
* SMAP L4 Global 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants (SPL4SMLM, DOI: 10.5067/KGLC3UH4TMAQ).
For each product, SMAP L-band brightness temperature data from descending and ascending half-orbit satellite passes (approximately 6:00 a.m. and 6:00 p.m. local solar time, respectively) are assimilated into a land surface model that is gridded using an Earth-fixed, global cylindrical 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) projection.
Parameter(s):
SURFACE SOIL MOISTURE
Platform(s):
SMAP
Sensor(s):
SMAP L-BAND RADIOMETER
Data Format(s):
HDF5
Temporal Coverage:
- 31 March 2015 to 27 August 2020
Temporal Resolution:
- 3 hour
Spatial Resolution:
- 9 km
- 9 km
Spatial Reference System(s):
- WGS 84 / NSIDC EASE-Grid 2.0 GlobalEPSG:6933
Spatial Coverage:
- N:85.044S:-85.044E:180W:-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
Data Access & Tools
This data set has been retired. There is a more recent version of these data.
Documentation
User Guide
ATBDs
General Resources
Quality Assessment Reports
Product Specification Documents
Help Articles
General Questions & FAQs
This article covers frequently asked questions about the NASA NSIDC DAAC's Earthdata cloud migration project and what it means to data users.
SMAP Ancillary data sets are used to produce SMAP Level-1, -2, -3, and -4 standard 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.
There are a few reasons that the soil moisture data values in SMAP Level-4 data products may vary from what you expect in a particular region. The first step a data user should take in investigating apparently anomalous values is to look at the rich quality information and other data flags c
The surface and root zone soil moisture estimates in the SMAP Level-4 soil moisture products are the outputs of a land surface model into which SMAP observations of brightness temperature have been assimilated.
How to Articles
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:
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
This How to guide outlines the steps for properly importing, projecting and visualizing HDF and NetCDF files in ArcMap. A couple of things to note before you start:
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.
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.