{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T21:28:16Z","timestamp":1779917296639,"version":"3.53.1"},"reference-count":50,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2018,10,2]],"date-time":"2018-10-02T00:00:00Z","timestamp":1538438400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Aquarius is an L-band radar\/radiometer instrument combination that has been designed to measure ocean salinity. It was launched on 10 June 2011 as part of the Aquarius\/SAC-D observatory. The observatory is a partnership between the United States National Aeronautics and Space Agency (NASA), which provided Aquarius, and the Argentinian space agency, Comisi\u03ccn Nacional de Actividades Espaciales (CONAE), which provided the spacecraft bus, Satelite de Aplicaciones Cientificas (SAC-D). The observatory was lost four years later on 7 June 2015 when a failure in the power distribution network resulted in the loss of control of the spacecraft. The Aquarius Mission formally ended on 31 December 2017. The last major milestone was the release of the final version of the salinity retrieval (Version 5). Version 5 meets the mission requirements for accuracy, and reflects the continuing progress and understanding developed by the science team over the lifetime of the mission. Further progress is possible, and several issues remained unresolved at the end of the mission that are relevant to future salinity retrievals. The understanding developed with Aquarius is being transferred to radiometer observations over the ocean from NASA\u2019s Soil Moisture Active Passive (SMAP) satellite, and salinity from SMAP with accuracy approaching that of Aquarius are already being produced.<\/jats:p>","DOI":"10.3390\/rs10101585","type":"journal-article","created":{"date-parts":[[2018,10,2]],"date-time":"2018-10-02T11:30:02Z","timestamp":1538479802000},"page":"1585","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Status of Aquarius and Salinity Continuity"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9335-0741","authenticated-orcid":false,"given":"David M.","family":"Le Vine","sequence":"first","affiliation":[{"name":"NASA\/Goddard Space Flight Center, Greenbelt, MD 20771, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9003-1182","authenticated-orcid":false,"given":"Emmanuel P.","family":"Dinnat","sequence":"additional","affiliation":[{"name":"NASA\/Goddard Space Flight Center, Greenbelt, MD 20771, USA"},{"name":"Chapman University, Orange, CA 92866, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5488-1566","authenticated-orcid":false,"given":"Thomas","family":"Meissner","sequence":"additional","affiliation":[{"name":"Remote Sensing Systems, 444 Tenth Street, Suite 200, Santa Rosa, CA 95401, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frank J.","family":"Wentz","sequence":"additional","affiliation":[{"name":"Remote Sensing Systems, 444 Tenth Street, Suite 200, Santa Rosa, CA 95401, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5573-1527","authenticated-orcid":false,"given":"Hsun-Ying","family":"Kao","sequence":"additional","affiliation":[{"name":"Earth and Space Research, 2101 Fourth Ave, Suite 1310, Seattle, WA 98121, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gary","family":"Lagerloef","sequence":"additional","affiliation":[{"name":"Earth and Space Research, 2101 Fourth Ave, Suite 1310, Seattle, WA 98121, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tong","family":"Lee","sequence":"additional","affiliation":[{"name":"Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2018,10,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Meissner, T., Wentz, F., and Le Vine, D.M. (2017). Aquarius Salinity Retrieval Algorithm: End of Mission Algorithm Theoretical Basis Document (ATBD). RSS Tech. Rep., 120117.","DOI":"10.56236\/RSS-be"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Meissner, T., Wentz, F.J., and Le Vine, D.M. (2018). The Salinity Retrieval Algorithm for the NASA Aquarius Version 5 and SMAP Version 3 Releases. Remote Sens., 10.","DOI":"10.3390\/rs10071121"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2040","DOI":"10.1109\/TGRS.2007.898092","article-title":"Aquarius: An instrument to monitor sea surface salinity from space","volume":"45","author":"Lagerloef","year":"2007","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"5401","DOI":"10.1109\/JSTARS.2015.2427159","article-title":"Status of Aquarius\/SAC-D and Aquarius Salinity Retrievals","volume":"8","author":"Dinnat","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1049","DOI":"10.1109\/36.921423","article-title":"Error sources and feasibility for microwave remote sensing of ocean surface salinity","volume":"39","author":"Yueh","year":"2001","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2434","DOI":"10.1109\/36.868900","article-title":"Estimates of Faraday rotation with passive microwave polarimetry for microwave remote sensing of Earth surfaces","volume":"38","author":"Yueh","year":"2000","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"520","DOI":"10.1109\/LGRS.2012.2211994","article-title":"Aquarius third stokes parameter measurements: Initial results","volume":"10","author":"Abraham","year":"2013","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"771","DOI":"10.1109\/TGRS.2002.1006342","article-title":"The effect of the ionosphere on remote sensing of sea surface salinity from space: Absorption and emission at L band","volume":"40","author":"Abraham","year":"2002","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Le Vine, D.M., Lagerloef, G.S.E., Ruf, C., Wentz, F., Yueh, S., Piepmeier, J., Lindstrom, E., and Dinnat, E. (2012, January 5\u20139). Aquarius: The instrument and initial results. Proceedings of the 12th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad), Rome, Italy.","DOI":"10.1109\/MicroRad.2012.6185226"},{"key":"ref_10","unstructured":"Wilson, W.J., Tanner, A., Pellerano, F., and Horgan, K. (2005). Ultrastable radiometers for future sea surface salinity missions. JPL Rep., D-31794."},{"key":"ref_11","unstructured":"Pellerano, F.A., Piepmeier, J., Triesky, M., Horgan, K., Forgione, J., Caldwell, J., Wilson, W.J., Yueh, S., Spencer, M., and McWatters, D. (August, January 31). The {A}quarius Ocean Salinity Mission High Stability {L-band} Radiometer. Proceedings of the IEEE International Conference on Geoscience and Remote Sensing Symposium, Denver, CO, USA."},{"key":"ref_12","unstructured":"Le Vine, D.M. (2002, January 24\u201328). ESTAR experience with RFI at L-band and implications for future passive microwave remote sensing from space. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium, Toronto, ON, Canada."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1398","DOI":"10.1109\/TGRS.2009.2031637","article-title":"L-band RFI as experienced during airborne campaigns in preparation for SMOS","volume":"48","author":"Skou","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"5416","DOI":"10.1109\/JSTARS.2015.2435493","article-title":"Aquarius L-Band Microwave Radiometer: 3 Years of Radiometric Performance and Systematic Effects","volume":"8","author":"Piepmeier","year":"2006","journal-title":"IEEE J. Sel. Topics Appl. Earth Obs. Remote Sens."},{"key":"ref_15","unstructured":"de Matthaeis, P., Peng, J., Piepmeier, J., and Le Vine, D. (AQ-014-PS-0029, 2018). Overview of Aquarius Radiometer Post-Launch Measturement Counts to Antenna Temperature Processing for Product Version 5, AQ-014-PS-0029."},{"key":"ref_16","unstructured":"(2018, October 01). Aquarius Project, \u201cATBD History, Available online: https:\/\/podaac.jpl.nasa.gov\/aquarius, December 31, 2017."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"7105","DOI":"10.1109\/TGRS.2016.2596100","article-title":"Sensitivity of Ocean Surface Salinity Measurements From Spaceborne L-Band Radiometers to Ancillary Sea Surface Temperature","volume":"54","author":"Meissner","year":"2016","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1016\/0022-4073(92)90127-P","article-title":"Atmospheric {60-GHz} oxygen spectrum: New laboratory measurements and line parameters","volume":"48","author":"Liebe","year":"1992","journal-title":"J. Quant. Spectrosc. Radiat. Transf."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"6499","DOI":"10.1002\/2014JC009837","article-title":"The emission and scattering of L-band microwave radiation from rough ocean surfaces and wind speed measurements from the Aquarius sensor","volume":"119","author":"Meissner","year":"2014","journal-title":"J. Geophys. Res. C Ocean."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1391","DOI":"10.1175\/BAMS-D-15-00032.1","article-title":"Satellite and In Situ Salinity: Understanding Near-Surface Stratification and Subfootprint Variability","volume":"97","author":"Boutin","year":"2016","journal-title":"Bull. Amer. Meteor. Soc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"34","DOI":"10.5670\/oceanog.2009.36","article-title":"The Argo Program: Observing the Global Oceans with Profiling Floats","volume":"22","author":"Roemmich","year":"2009","journal-title":"Oceanography"},{"key":"ref_22","unstructured":"Kao, H.-Y., Lagerloef, G., Lee, T., Melnichenko, O., and Hacker, P. (2018). Aquarius Salinity Validation Analysis, AQ-014-PS-0016."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1016\/j.jmarsys.2005.09.016","article-title":"The HYCOM (HYbrid Coordinate Ocean Model) data assimilative system","volume":"65","author":"Chassignet","year":"2007","journal-title":"J. Mar. Syst."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3857","DOI":"10.1002\/2016GL068822","article-title":"Consistency of Aquarius sea surface salinity with Argo products on various spatial and temporal scales","volume":"43","author":"Lee","year":"2016","journal-title":"Geophys. Res. Lett."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1109\/JOE.1977.1145319","article-title":"An improved model for the dielectric constant of sea water at microwave frequencies","volume":"AP-25","author":"Klein","year":"1977","journal-title":"IEEE J. Ocean. Eng."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3004","DOI":"10.1109\/TGRS.2011.2179662","article-title":"The Emissivity of the Ocean Surface Between 6 and 90 GHz Over a Large Range of Wind Speeds and Earth Incidence Angles","volume":"50","author":"Meissner","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"6964","DOI":"10.1109\/TGRS.2017.2737419","article-title":"L-Band Model Function of the Dielectric Constant of Seawater","volume":"55","author":"Zhou","year":"2017","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1829","DOI":"10.1109\/TGRS.2004.833393","article-title":"High-Stability L-Band Radiometer Measurements of Saltwater","volume":"42","author":"Wilson","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"5433","DOI":"10.1109\/JSTARS.2015.2496362","article-title":"Aquarius L-band Radiometers Calibration Using Cold Sky Observations","volume":"8","author":"Dinnat","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_30","unstructured":"Scripps Institution of Oceanography (2018, October 01). Global gridded NetCDF Argo only dataset produced by optimal interpolation. Available online: http:\/\/apdrc.soest.ucsd.edu\/Gridded_fields.html."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5416","DOI":"10.1109\/JSTARS.2015.2435493","article-title":"Aquarius L-Band Microwave Radiometer: 3 Years of Radiometric Performance and Systematic Effects","volume":"8","author":"Piepmeier","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_32","unstructured":"Misra, S. (2017, January 22\u201326). Enabling the Next Generation of Salinity, Sea Surface Temperature and Wind Meaurements from Space: Instrument Challenges. Proceedings of the Global Ocean Salinity and Water Cycle Workshop, Woods Hole, MA, USA."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3137","DOI":"10.1109\/TGRS.2008.2000629","article-title":"Impact of sun glint on salinity remote sensing: An example with the aquarius radiometer","volume":"46","author":"Dinnat","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Dinnat, E.P., Boutin, J., Yin, X., Le Vine, D., Waldteufel, P., and Vergely, J.-L. (2014, January 16\u201323). Comparison of SMOS and Aquarius sea surface salinity and analysis of possible causes for the differences. Proceedings of the 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), Beijing, China.","DOI":"10.1109\/URSIGASS.2014.6929701"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1836","DOI":"10.1109\/TGRS.2004.831888","article-title":"The complex dielectric constant of pure and sea water from microwave satellite observations","volume":"42","author":"Meissner","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Lang, R., Zhou, Y., Dinnat, E., and Le Vine, D. (2017, January 23\u201328). The Dielectric Constant Model Function and Implications for Remote Sensing of Salinity. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Fort Worth, TX, USA.","DOI":"10.1109\/IGARSS.2017.8127771"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1002\/2015RS005776","article-title":"Accurate measurements of the dielectric constant of seawater at L band","volume":"51","author":"Lang","year":"2016","journal-title":"Radio Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"688","DOI":"10.1109\/JPROC.2010.2040550","article-title":"Aquarius and remote sensing of sea surface salinity from space","volume":"98","author":"Lagerloef","year":"2010","journal-title":"Proc. IEEE"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Dinnat, E.P., Le Vine, D.M., Bindlish, R., Piepmeier, J.R., and Brown, S.T. (2014, January 24\u201327). Aquarius whole range calibration: Celestial Sky, ocean, and land targets. Proceedings of the 13th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad), Pasadena, CA, USA.","DOI":"10.1109\/MicroRad.2014.6878937"},{"key":"ref_40","unstructured":"Le Vine, D.M., and Dinnat, E.P. (2018, October 01). Whole Range Calibration: Version 5.WR, Available online: https:\/\/podaac.jpl.nasa.gov\/aquarius."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Dinnat, E.P., Le Vine, D.M., and Hong, L. (2018, January 22\u201327). Aquaruius Final Release Product and Full Range Calibration of L-Band Radiometer. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium (IGARSS2018), Valencia, Spain.","DOI":"10.1109\/IGARSS.2018.8519305"},{"key":"ref_42","unstructured":"Dinnat, E., Le Vine, D., Soldo, Y., and de Matthaeis, P. (2018, January 27\u201330). Theoretical algorithm for the retrieval of sea surface salinity from SMAP observations at L-band. Proceedings of the 15th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, Cambridge, MA, USA."},{"key":"ref_43","unstructured":"Meissner, T., Wentz, F., Ricciardulli, L., Mears, C., and Manaster, A. (2018). Ocean Surface Salinity and Wind Speed from the SMAP L-Band Radiometer. Microwave Radiometry and Remote Sensing of the Earth\u2019s Surface and Atmosphere, VSP."},{"key":"ref_44","unstructured":"Meissner, T., and Wentz, F. (2016). Remote Sensing Systems SMAP Ocean Surface Salinities Level 2C, Version 2.0 Validated Release, Remote Sensing Systems."},{"key":"ref_45","unstructured":"Sabia, R. (2018, January 11\u201316). SMOS Pilot-Mission Exploitation Platform (PI-MEP): A Hub for Validation and Expolitation of ESA SMOS Sea Surface Salinity Data. Proceedings of the Ocean Sciences Meeting, Portland, OR, USA."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Dong, X., Shi, J., Zhang, S., Liu, H., Wang, Z., Zhu, D., Zuo, L., Chen, C., and Chen, W. (2016, January 10\u201315). Prelminary design of water cycle observation mission (WCOM). Proceedings of the IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China.","DOI":"10.1109\/IGARSS.2016.7729887"},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Shi, J., Dong, X., Zhao, T., Du, Y., Liu, H., Wang, Z., Zhu, D., Ji, D., Xiong, C., and Jiang, L. (2016, January 10\u201315). The Water Cycle Observation Mission (WCOM): Overview. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China.","DOI":"10.1109\/IGARSS.2016.7729886"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Xu, X., Yun, R., Dong, X., Zhu, D., Yin, X., and Liu, H. (2016, January 10\u201315). Data Pre-Processing of MICAP (Microwave Imager Combined Active and Passive) Scatterometer. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China.","DOI":"10.1109\/IGARSS.2016.7730246"},{"key":"ref_49","unstructured":"Dinnat, E., de Amici, G., Le Vine, D., and Piepmeier, J. (2018, January 27\u201330). Next generation spaceborne instrument for monitoring ocean salinity with application to the coastal zone and cryosphere. Proceedings of the 15th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, Cambridge, MA, USA."},{"key":"ref_50","unstructured":"Brown, S. (2017, January 22\u201326). A Next Generation Spaceborne Ocean State Observatory: Surface Salinity, Temperature and Ocean Winds from Equator to Pole. Proceedings of the Globasl Ocean Salinity and the Water Cycle Workshop, Woods Hole, MA, USA."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/10\/1585\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:23:47Z","timestamp":1760196227000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/10\/10\/1585"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,10,2]]},"references-count":50,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2018,10]]}},"alternative-id":["rs10101585"],"URL":"https:\/\/doi.org\/10.3390\/rs10101585","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,10,2]]}}}