RSS SMAP Level 3 Sea Surface Salinity Standard Mapped Image Monthly V5.0 Validated Dataset

The version 5.0 SMAP-SSS level 3, monthly gridded product is based on the fourth release of the validated standard mapped sea surface salinity (SSS) data from the NASA Soil Moisture Active Passive (SMAP) observatory, produced operationally by Remote Sensing Systems (RSS) with a one-month latency. The major changes in Version 5.0 from Version 4 are: (1) the addition of formal uncertainty estimates to all salinity retrieval products. (2) Sea-ice flagging and sea-ice side-lobe correction based on direct ingestion of AMSR-2 brightness temperature (TB) measurements. This is in contrast to Version 4 and earlier versions in which the sea-ice correction was based on an external sea-ice concentration product. The use of AMSR-2 TB measurements in the SMAP Version 5 products allows for salinity retrievals closer to the sea-ice edge and aids in the detection of large icebergs near the Antarctic. Monthly data files for this product are averages over one-month time intervals. SMAP data begins on April 1,2015 and is ongoing, with a one-month latency in processing and availability. L3 products are global in extent with a default spatial resolution of approximately 70KM. The datasets are gridded at 0.25degree x 0.25degree. Note that while a SSS 40KM variable is also included in the product, for most open ocean applications, the default SSS variable (70KM) is best used as they are significantly less noisy than the 40KM data. The SMAP satellite is in a near-polar orbit at an inclination of 98 degrees and an altitude of 685 km. It has an ascending node time of 6 pm and is sun-synchronous. With its 1000km swath, SMAP achieves global coverage in approximately 3 days, but has an exact orbit repeat cycle of 8 days. On board instruments include a highly sensitive L-band radiometer operating at 1.41GHz and an L-band 1.26GHz radar sensor providing complementary active and passive sensing capabilities. Malfunction of the SMAP scatterometer on 7 July, 2015, has necessitated the use of collocated wind speed, primarily from WindSat, for the surface roughness correction required for the surface salinity retrieval.

Data and Resources

Additional Info

Field	Value
Maintainer	Earthdata Forum
Last Updated	November 3, 2026, 01:46 (UTC)
Created	April 1, 2025, 18:33 (UTC)
Identifier	10.5067/SMP50-3SMCS
Modified	2026-10-26T22:16:09Z
Theme	{"Earth Science"}
accessLevel	public
bureauCode	{026:00}
catalog_conformsTo	https://project-open-data.cio.gov/v1.1/schema
harvest_object_id	21beab42-faec-4803-a7bf-b843d1cc1c3b
harvest_source_id	b99e41c6-fe79-4c19-bbc3-9b6c8111bfac
harvest_source_title	Science Discovery Engine
license	https://www.usa.gov/government-works
programCode	{026:000}
publisher	NASA/JPL/PODAAC;RSS
resource-type	Dataset
source_datajson_identifier	true
source_hash	3e9c65d3ff1b6804180127f118f2c00e6f984f97a66bea062b0641e4f01bbd23
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spatial	["CARTESIAN", [{"WestBoundingCoordinate": -180.0, "SouthBoundingCoordinate": -90, "EastBoundingCoordinate": 180.0, "NorthBoundingCoordinate": 90}]]