A new global product, combining Aquarius and SMAP SSS observations into a continuous and consistent SSS time series, is available for ocean research and applications.

The new dataset covers the period from September 2011 to present. The beginning segment, from September 2011 to June 2015, utilizes data from the Aquarius satellite and is based on optimum interpolation analysis (OI SSS; Melnichenko et al., 2016). The analysis (weekly maps) is produced on a 0.25-degree grid at a 4-day interval and uses a dedicated bias-correction algorithm to correct the satellite retrievals for large-scale biases with respect to in situ data. The time series is continued with the SMAP satellite-based SSS data provided by Remote Sensing Systems (RSS). SMAP SSS fields are produced on a 0.25-degree grid at a 4-day interval from Level-2 (swath) data using the OI algorithm. To ensure consistency and continuity in the data record, SMAP SSS fields are further adjusted using a set of optimally designed spatial filters to reduce small-scale noise and, at the same time, to ensure that the data record is consistent across the scales. For the overlap period (April-May 2015), the data from the two satellites are averaged together to ensure a smooth transition from one dataset to another. A detailed description of the mapping methodology can be found in a Technical Note, which also includes results of statistical validation of the product.

The Aquarius/SMAP OISSS analysis (weekly average maps) is produced on a uniform grid with 0.25° resolution at a 4-day interval for the period September 2011 - present.

Digital data of the analysis (netCDF files) are available here.

File Naming Convention:

- OISSS_L4_multimission_global_7d_v1.0_YYYY-MM-DD,

where

- V1.0 - version v1.0,

- [YYYY] is the year,

- [MM] is the month, and

- [DD] is the day of the weekly (7d) SSS map in the file.

Monthly SSS and monthly SSS anomaly data are available here.The anomalies are computed relative to the product-based monthly climatology (monthly averages over a 10-year period from September 2011 to August 2021; see Description).

File Naming Convention:

- OISSS_L4_multimission_global_monthly_v1.0_YYYY-MM,

where

- V1.0 - version v1.0,

- [YYYY] is the year,

- [MM] is the month of the monthly SSS map in the file.

For your convenience, monthly OISSS maps (PNG files) are available here.

Monthly OISSS anomaly maps (PNG files) are available here.

The OISSS climatology maps (PNG files) are available here.