Aquarius/SMAP Optimum Interpolation Maps: Sea Surface Salinity

The sea surface salinity (SSS) optimum interpolation (OI) product combines observations from NASA's Aquarius/SAC-D and Soil Moisture Active-Passive (SMAP) satellite missions into a continuous and consistent multi-satellite SSS data record.

The dataset covers the period from September 2011 to February 2021. The beginning segment, from September 2011 to June 2015, utilizes data from the Aquarius satellite and is based on OI analysis (OI SSS; Melnichenko et al., 2016). The analysis 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 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. Measurements from the European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite are used to fill the gap in SMAP observations during June-July 2019, when the SMAP satellite was in a safe mode and did not deliver scientific data.

Thanks to this long, continuous data record, it is possible to compute monthly climatology data. Climatology data are computed over a 9-year period from September 2011 to August 2020 (view climatology maps). In addition, anomaly data are computed relative to the OI SSS product-based monthly climatology (view anomaly maps).

Reference
Melnichenko, O., P. Hacker., N. Maximenko, G. Lagerloef, and J. Potemra (2016), Optimum interpolation analysis of Aquarius sea surface salinity, J. Geophys. Res. Oceans, 121, 602-616, doi:10.1002/2015JC011343.
Resources

Click on the images (below) for a closer view. From there, you can click the left/right arrows to move from month to month. After you've selected a specific map, you can click on the caption to view anomaly data for that month/year. Can't see the image captions? Try resizing your browser window to allow toggling between SSS and anomaly maps.

Global map of monthly sea surface salinity data, February 2021
February 2021
Global map of monthly sea surface salinity data, January 2021
January 2021
Global map of monthly sea surface salinity data, December 2020
December 2020
Global map of monthly sea surface salinity data, November 2020
November 2020
Global map of monthly sea surface salinity data, October 2020
October 2020
Global map of monthly sea surface salinity data, September 2020
September 2020
Global map of monthly sea surface salinity data, August 2020
August 2020
Global map of monthly sea surface salinity data, July 2020
July 2020
Global map of monthly sea surface salinity data, June 2020
June 2020
Global map of monthly sea surface salinity data, May 2020
May 2020
Global map of monthly sea surface salinity data, April 2020
April 2020
Global map of monthly sea surface salinity data, March 2020
March 2020
Global map of monthly sea surface salinity data, February 2020
February 2020
Global map of monthly sea surface salinity data, January 2020
January 2020
Global map of monthly sea surface salinity data, December 2019
December 2019
Global map of monthly sea surface salinity data, November 2019
November 2019
Global map of monthly sea surface salinity data, October 2019
October 2019
Global map of monthly sea surface salinity data, September 2019
September 2019
Global map of monthly sea surface salinity data, August 2019
August 2019
Global map of monthly sea surface salinity data, July 2019
July 2019
Global map of monthly sea surface salinity data, June 2019
June 2019
Global map of monthly sea surface salinity data, May 2019
May 2019
Global map of monthly sea surface salinity data, April 2019
April 2019
Global map of monthly sea surface salinity data, March 2019
March 2019
Global map of monthly sea surface salinity data, February 2019
February 2019
Global map of monthly sea surface salinity data, January 2019
January 2019
Global map of monthly sea surface salinity data, December 2018
December 2018
Global map of monthly sea surface salinity data, November 2018
November 2018
Global map of monthly sea surface salinity data, October 2018
October 2018
Global map of monthly sea surface salinity data, September 2018
September 2018
Global map of monthly sea surface salinity data, August 2018
August 2018
Global map of monthly sea surface salinity data, July 2018
July 2018
Global map of monthly sea surface salinity data, June 2018
June 2018
Global map of monthly sea surface salinity data, May 2018
May 2018
Global map of monthly sea surface salinity data, April 2018
April 2018
Global map of monthly sea surface salinity data, March 2018
March 2018
Global map of monthly sea surface salinity data, February 2018
February 2018
Global map of monthly sea surface salinity data, January 2018
January 2018
Global map of monthly sea surface salinity data, December 2017
December 2017
Global map of monthly sea surface salinity data, November 2017
November 2017
Global map of monthly sea surface salinity data, October 2017
October 2017
Global map of monthly sea surface salinity data, September 2017
September 2017
Global map of monthly sea surface salinity data, August 2017
August 2017
Global map of monthly sea surface salinity data, July 2017
July 2017
Global map of monthly sea surface salinity data, June 2017
June 2017
Global map of monthly sea surface salinity data, May 2017
May 2017
Global map of monthly sea surface salinity data, April 2017
April 2017
Global map of monthly sea surface salinity data, March 2017
March 2017
Global map of monthly sea surface salinity data, February 2017
February 2017
Global map of monthly sea surface salinity data, January 2017
January 2017
Global map of monthly sea surface salinity data, December 2016
December 2016
Global map of monthly sea surface salinity data, November 2016
November 2016
Global map of monthly sea surface salinity data, October 2016
October 2016
Global map of monthly sea surface salinity data, September 2016
September 2016
Global map of monthly sea surface salinity data, August 2016
August 2016
Global map of monthly sea surface salinity data, July 2016
July 2016
Global map of monthly sea surface salinity data, June 2016
June 2016
Global map of monthly sea surface salinity data, May 2016
May 2016
Global map of monthly sea surface salinity data, April 2016
April 2016
Global map of monthly sea surface salinity data, March 2016
March 2016
Global map of monthly sea surface salinity data, February 2016
February 2016
Global map of monthly sea surface salinity data, January 2016
January 2016
Global map of monthly sea surface salinity data, December 2015
December 2015
Global map of monthly sea surface salinity data, November 2015
November 2015
Global map of monthly sea surface salinity data, October 2015
October 2015
Global map of monthly sea surface salinity data, September 2015
September 2015
Global map of monthly sea surface salinity data, August 2015
August 2015
Global map of monthly sea surface salinity data, July 2015
July 2015
Global map of monthly sea surface salinity data, June 2015
June 2015
Global map of monthly sea surface salinity data, May 2015
May 2015
Global map of monthly sea surface salinity data, April 2015
April 2015
Global map of monthly sea surface salinity data, March 2015
March 2015
Global map of monthly sea surface salinity data, February 2015
February 2015
Global map of monthly sea surface salinity data, January 2015
January 2015
Global map of monthly sea surface salinity data, December 2014
December 2014
Global map of monthly sea surface salinity data, November 2014
November 2014
Global map of monthly sea surface salinity data, October 2014
October 2014
Global map of monthly sea surface salinity data, September 2014
September 2014
Global map of monthly sea surface salinity data, August 2014
August 2014
Global map of monthly sea surface salinity data, July 2014
July 2014
Global map of monthly sea surface salinity data, June 2014
June 2014
Global map of monthly sea surface salinity data, May 2014
May 2014
Global map of monthly sea surface salinity data, April 2014
April 2014
Global map of monthly sea surface salinity data, March 2014
March 2014
Global map of monthly sea surface salinity data, February 2014
February 2014
Global map of monthly sea surface salinity data, January 2014
January 2014
Global map of monthly sea surface salinity data, December 2013
December 2013
Global map of monthly sea surface salinity data, November 2013
November 2013
Global map of monthly sea surface salinity data, October 2013
October 2013
Global map of monthly sea surface salinity data, September 2013
September 2013
Global map of monthly sea surface salinity data, August 2013
August 2013
Global map of monthly sea surface salinity data, July 2013
July 2013
Global map of monthly sea surface salinity data, June 2013
June 2013
Global map of monthly sea surface salinity data, May 2013
May 2013
Global map of monthly sea surface salinity data, April 2013
April 2013
Global map of monthly sea surface salinity data, March 2013
March 2013
Global map of monthly sea surface salinity data, February 2013
February 2013
Global map of monthly sea surface salinity data, January 2013
January 2013
Global map of monthly sea surface salinity data, December 2012
December 2012
Global map of monthly sea surface salinity data, November 2012
November 2012
Global map of monthly sea surface salinity data, October 2012
October 2012
Global map of monthly sea surface salinity data, September 2012
September 2012
Global map of monthly sea surface salinity data, August 2012
August 2012
Global map of monthly sea surface salinity data, July 2012
July 2012
Global map of monthly sea surface salinity data, June 2012
June 2012
Global map of monthly sea surface salinity data, May 2012
May 2012
Global map of monthly sea surface salinity data, April 2012
April 2012
Global map of monthly sea surface salinity data, March 2012
March 2012
Global map of monthly sea surface salinity data, February 2012
February 2012
Global map of monthly sea surface salinity data, January 2012
January 2012
Global map of monthly sea surface salinity data, December 2011
December 2011
Global map of monthly sea surface salinity data, November 2011
November 2011
Global map of monthly sea surface salinity data, October 2011
October 2011
Global map of monthly sea surface salinity data, September 2011
September 2011