"Fronts are (the) hot spots of marine life." - Igor M. Belkin
Oceanic fronts are narrow zones of enhanced horizontal gradients of water properties (temperature, salinity, nutrients, etc.) that separate broader areas of different water masses.
Living creatures seek out such oceanic features as habitats of choice for foraging, reproduction, recruitment, and migration.
Visual observations from satellites and orbital manned stations corroborate such findings: large and mesoscale features such as fronts have been recognized as ecologically important by marine biologists for some time, while fishermen have long exploited their potential.
Despite this, their use in everyday activities and long-term planning of marine fisheries remained limited until recently due to a lack of computer software for efficient and effective processing of vast amounts of satellite data.
This situation has changed quite dramatically over the last 10 years: maps are now routinely generated by new computer algorithms that can detect fronts of various oceanic properties in satellite images.
Click on the images below to compare maps of sea surface salinity and salinity gradients generated from satellite data by Earth & Space Research (ESR).
View all maps at 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 Aquarius, January 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 Aquarius, January 2015. 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 Aquarius, March 2015. 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.
Monthly global data files are provided by ESR for the following instruments: Aquarius, SMAP, SMAP RF, SMOS, and Argo. Daily global data sets, organized by year, 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.
