"The ocean has a life of its own. Its tides, whirlpools, currents and eddies are a testament to its conflicting emotions." – Anthony T. Hincks
Ocean fronts can form where water masses collide. Defined by stark changes in temperature or salinity, these liquid boundaries can concentrate nutrients and enhance productivity. Living creatures seek out these oceanic features as habitats of choice for foraging, reproduction, recruitment, and migration.
Fronts and other mesoscale features such as eddies have been recognized as ecologically important by marine biologists – and by some in the fishing industry – for many years. In addition, fine-scale salinity gradients are useful for tracking of climate-relevant ocean motions such as tropical instability waves and the meandering of the Gulf Stream.
Until recently, the use of satellite data in everyday activities and long-term planning of marine fisheries has been limited. This situation has changed quite dramatically in the past decade: maps are now routinely generated by new computer algorithms that can detect fronts of various oceanic properties from satellite data.
Click on the images below to compare selected maps of sea surface salinity and salinity gradients produced from satellite data by Earth & Space Research (ESR).
View all maps at ESR.
Global
Global
Global maps from SMAP, December 2020. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Amazon River Plume
Amazon River Plume
Amazon River plume from Aquarius, May 2015. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Antarctic Ocean
Antarctic Ocean
Antarctic Ocean from Aquarius, January 2015. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Arctic Ocean
Arctic Ocean
Arctic Ocean from SMAP, September 2015. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
East Tropical Pacific Ocean
East Tropical Pacific Ocean
East Tropical Pacific Ocean from Aquarius, February 2015. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Gulf Stream
Gulf Stream
Gulf Stream from SMAP, January 2020. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Indian Ocean
Indian Ocean
Indian Ocean from Aquarius, January 2015. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Subtropical North Atlantic Ocean
Subtropical North Atlantic Ocean
Subtropical North Atlantic Ocean from Aquarius, May 2015. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Tropical Pacific Ocean
Tropical Pacific Ocean
Tropical Pacific Ocean from SMAP, April 2020. Left: sea surface salinity. Right: salinity gradient. View maps from other dates and platforms here. Credit: ESR.
Related Publications
Belkin, I. (2021). Remote Sensing of Ocean Fronts in Marine Ecology and Fisheries, Remote Sens. 2021, 13(5), 883, doi: 10.3390/rs13050883.
Vazquez-Cuervo, J., Gomez-Valdes, J., and Bouali, M. (2020). Comparison of Satellite-Derived Sea Surface Temperature and Sea Surface Salinity Gradients Using the Saildrone California/Baja and North Atlantic Gulf Stream Deployments, Remote Sens., 12(11), 1839, doi: 10.3390/rs12111839.
Reul, N., Grodsky, S., Arias., M., Boutin, J., Catany, R., Chapron, B., D'Amico, F., Dinnat, E., Donlon, C., Fore, A., Fournier, S., Guimbard, S., Hasson, A., Kolodziejczyk, N., Lagerloef, G., Lee, T., Le Vine, D., Lindstrom, E., Maes, C., Mecklenburg, S., Meissner, T., Olmedo, E., Sabia, R., Tenerelli, J., Thouvenin-Masson, C., Turiel, A., Vergely, J., Wentz, and Yueh, S. (2020). Sea Surface Salinity Estimates from Spaceborne L-band Radiometers: An Overview of the First Decade of Observation (2010–2019), Remote Sens. Envir., 242, 111769, doi: 10.1016/j.rse.2020.111769.
Katsura, S. and Sprintall, J. (2020). Seasonality and Formation of Barrier Layers and Associated Temperature Inversions in the Eastern Tropical North Pacific, J. Phys. Oceanogr., doi: 10.1175/JPO-D-19-0194.1.
Drushka, K., Asher, W.E., Sprintall, J., Gille, S.T., and Hoang, C. (2019). Global Patterns of Submesoscale Surface Salinity Variability, J. Phys. Oceanogr., 49 (7), 1669-1685, doi: 10.1175/JPO-D-19-0018.1.
Brokaw, R.J., Subrahmanyam, B., and Morey, S.L. (2019). Loop Current and Eddy-Driven Salinity Variability in the Gulf of Mexico, Geophys. Res. Lett., 46 (11), 5978-5986, doi: 10.1029/2019GL082931.
Grodsky, S.A., Vandemark, D., and Feng, H. (2018). Assessing Coastal SMAP Surface Salinity Accuracy and Its Application to Monitoring Gulf of Maine Circulation Dynamics, Remote Sens., 10 (8), doi: 10.3390/rs10081232.
Jaeger, G.S., and Mahadevan, A. (2018). Submesoscale-selective Compensation of Fronts in a Salinity-stratified Ocean, Sci. Adv., 4 (2), e1701504, doi: 10.1126/sciadv.1701504.
Ramachandran, S. and Tandon, A. (2018). Submesoscale Processes at Shallow, Salinity Fronts in the Bay of Bengal: Observations During the Winter Monsoon, J. Phys. Oceanogr., doi: 10.1175/JPO-D-16-0283.1.
Hormann, V., Centurioni, L.R., Mahadevan, A., Essink, S., D’Asaro, E.A., and Kumar, B.P. (2016). Variability of Near-surface Circulation and Sea Surface Salinity Observed from Lagrangian Drifters in the Northern Bay of Bengal During the Waning 2015 Southwest Monsoon, Oceanography, 29 (2), 124-133, doi: 10.5670/oceanog.2016.45.
Yu, L. (2015). Sea-surface Salinity Fronts and Associated Salinity Minimum Zones in the Tropical Ocean, J. Geophys. Res.-Oceans, 120 (6), 4205-4225, doi: 10.1002/2015JC010790.
Yu, L. (2014). Coherent Evidence from Aquarius and Argo for the Existence of a Shallow Low-salinity Convergence Zone Beneath the Pacific ITCZ, J. Geophys. Res.-Oceans, 119 (11), 7625-7644, doi: 10.1002/2014JC010030.
Asher, W.E., Jessup, A.T., Branch, R., and Clark, D. (2014). Observations of Rain-induced Near-surface Salinity Anomalies, J. Geophys. Res.-Oceans, 119 (8), 5483-5500, doi: 10.1002/2014JC009954.
Qu, T.D. and Yu, J.Y. (2014). ENSO Indices from Sea Surface Salinity Observed by Aquarius and Argo, J. Oceanogr., 70 (4), 367-375, doi: 10.1007/s10872-014-0238-4.
Belkin, I.M, Cornillon, P.C., and Sherman, K. (2009). Fronts in Large Marine Ecosystems, Prog. Oceanogr., 81 (1-4), 223-236, doi: 10.1016/j.pocean.2009.04.015.
Belkin, I.M. and Cornillon, P.C. (2007). Fronts in the World Ocean’s Large Marine Ecosystems, International Council for the Exploration of the Sea (ICES), ICES CM 2007/D:21 Theme Session D: Comparative Marine Ecosystem Structure and Function: Descriptors and Characteristics.
Oceanic fronts shape marine ecosystems; therefore front mapping and characterization are among the most important aspects of physical oceanography. Here the authors report on the first global remote sensing survey of fronts in large marine ecosystems.
Reference
Belkin, I.M., Cornillon, P.C., and Sherman, K. (2009).
View the full paper.
This paper provides a concise review of the remote sensing of ocean fronts in marine ecology and fisheries, with a particular focus on the most popular front detection algorithms and techniques.
The goal of this website is to provide a systematic estimation and assessment of satellite SSS gradients over the global ocean, including spatiotemporal variability and regional analyses.
Monthly data sets are provided for Aquarius, SMAP, SMAP RF, SMOS, and Argo. Daily data sets are available for Aquarius, SMAP, and SMOS.
Vazquez-Cuervo, J., Gomez-Valdes, J., and Bouali, M. (2020). Comparison of Satellite-Derived Sea Surface Temperature and Sea Surface Salinity Gradients Using the Saildrone California/Baja and North Atlantic Gulf Stream Deployments, Remote Sens., 12(11), 1839, doi: 10.3390/rs12111839.
Reul, N., Grodsky, S., Arias., M., Boutin, J., Catany, R., Chapron, B., D'Amico, F., Dinnat, E., Donlon, C., Fore, A., Fournier, S., Guimbard, S., Hasson, A., Kolodziejczyk, N., Lagerloef, G., Lee, T., Le Vine, D., Lindstrom, E., Maes, C., Mecklenburg, S., Meissner, T., Olmedo, E., Sabia, R., Tenerelli, J., Thouvenin-Masson, C., Turiel, A., Vergely, J., Wentz, and Yueh, S. (2020). Sea Surface Salinity Estimates from Spaceborne L-band Radiometers: An Overview of the First Decade of Observation (2010–2019), Remote Sens. Envir., 242, 111769, doi: 10.1016/j.rse.2020.111769.
Katsura, S. and Sprintall, J. (2020). Seasonality and Formation of Barrier Layers and Associated Temperature Inversions in the Eastern Tropical North Pacific, J. Phys. Oceanogr., doi: 10.1175/JPO-D-19-0194.1.
Drushka, K., Asher, W.E., Sprintall, J., Gille, S.T., and Hoang, C. (2019). Global Patterns of Submesoscale Surface Salinity Variability, J. Phys. Oceanogr., 49 (7), 1669-1685, doi: 10.1175/JPO-D-19-0018.1.
Brokaw, R.J., Subrahmanyam, B., and Morey, S.L. (2019). Loop Current and Eddy-Driven Salinity Variability in the Gulf of Mexico, Geophys. Res. Lett., 46 (11), 5978-5986, doi: 10.1029/2019GL082931.
Grodsky, S.A., Vandemark, D., and Feng, H. (2018). Assessing Coastal SMAP Surface Salinity Accuracy and Its Application to Monitoring Gulf of Maine Circulation Dynamics, Remote Sens., 10 (8), doi: 10.3390/rs10081232.
Jaeger, G.S., and Mahadevan, A. (2018). Submesoscale-selective Compensation of Fronts in a Salinity-stratified Ocean, Sci. Adv., 4 (2), e1701504, doi: 10.1126/sciadv.1701504.
Ramachandran, S. and Tandon, A. (2018). Submesoscale Processes at Shallow, Salinity Fronts in the Bay of Bengal: Observations During the Winter Monsoon, J. Phys. Oceanogr., doi: 10.1175/JPO-D-16-0283.1.
Hormann, V., Centurioni, L.R., Mahadevan, A., Essink, S., D’Asaro, E.A., and Kumar, B.P. (2016). Variability of Near-surface Circulation and Sea Surface Salinity Observed from Lagrangian Drifters in the Northern Bay of Bengal During the Waning 2015 Southwest Monsoon, Oceanography, 29 (2), 124-133, doi: 10.5670/oceanog.2016.45.
Yu, L. (2015). Sea-surface Salinity Fronts and Associated Salinity Minimum Zones in the Tropical Ocean, J. Geophys. Res.-Oceans, 120 (6), 4205-4225, doi: 10.1002/2015JC010790.
Yu, L. (2014). Coherent Evidence from Aquarius and Argo for the Existence of a Shallow Low-salinity Convergence Zone Beneath the Pacific ITCZ, J. Geophys. Res.-Oceans, 119 (11), 7625-7644, doi: 10.1002/2014JC010030.
Asher, W.E., Jessup, A.T., Branch, R., and Clark, D. (2014). Observations of Rain-induced Near-surface Salinity Anomalies, J. Geophys. Res.-Oceans, 119 (8), 5483-5500, doi: 10.1002/2014JC009954.
Qu, T.D. and Yu, J.Y. (2014). ENSO Indices from Sea Surface Salinity Observed by Aquarius and Argo, J. Oceanogr., 70 (4), 367-375, doi: 10.1007/s10872-014-0238-4.
Belkin, I.M, Cornillon, P.C., and Sherman, K. (2009). Fronts in Large Marine Ecosystems, Prog. Oceanogr., 81 (1-4), 223-236, doi: 10.1016/j.pocean.2009.04.015.
Belkin, I.M. and Cornillon, P.C. (2007). Fronts in the World Ocean’s Large Marine Ecosystems, International Council for the Exploration of the Sea (ICES), ICES CM 2007/D:21 Theme Session D: Comparative Marine Ecosystem Structure and Function: Descriptors and Characteristics.
