OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data

Retrieving information concerning the interior of the ocean using satellite remote sensing data has a major impact on studies of ocean dynamic and climate changes; however, the lack of information within the ocean limits such studies about the global ocean. In this paper, an artificial neural networ...

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Main Authors: Hua Su, Haojie Zhang, Xupu Geng, Tian Qin, Wenfang Lu, Xiao-Hai Yan
Format: Article
Language:English
Published: MDPI AG 2020-07-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/12/14/2294
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author Hua Su
Haojie Zhang
Xupu Geng
Tian Qin
Wenfang Lu
Xiao-Hai Yan
author_facet Hua Su
Haojie Zhang
Xupu Geng
Tian Qin
Wenfang Lu
Xiao-Hai Yan
author_sort Hua Su
collection DOAJ
description Retrieving information concerning the interior of the ocean using satellite remote sensing data has a major impact on studies of ocean dynamic and climate changes; however, the lack of information within the ocean limits such studies about the global ocean. In this paper, an artificial neural network, combined with satellite data and gridded Argo product, is used to estimate the ocean heat content (OHC) anomalies over four different depths down to 2000 m covering the near-global ocean, excluding the polar regions. Our method allows for the temporal hindcast of the OHC to other periods beyond the 2005–2018 training period. By applying an ensemble technique, the hindcasting uncertainty could also be estimated by using different 9-year periods for training and then calculating the standard deviation across six ensemble members. This new OHC product is called the Ocean Projection and Extension neural Network (OPEN) product. The accuracy of the product is accessed using the coefficient of determination (R<sup>2</sup>) and the relative root-mean-square error (RRMSE). The feature combinations and network architecture are optimized via a series of experiments. Overall, intercomparison with several routinely analyzed OHC products shows that the OPEN OHC has an R<sup>2</sup> larger than 0.95 and an RRMSE of <0.20 and presents notably accurate trends and variabilities. The OPEN product can therefore provide a valuable complement for studies of global climate changes.
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spelling doaj.art-b8ac1c4b107a482392a2e217841eb04c2023-11-20T07:05:19ZengMDPI AGRemote Sensing2072-42922020-07-011214229410.3390/rs12142294OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing DataHua Su0Haojie Zhang1Xupu Geng2Tian Qin3Wenfang Lu4Xiao-Hai Yan5Key Laboratory of Spatial Data Mining and Information Sharing of Ministry of Education, National & Local Joint Engineering Research Centre of Satellite Geospatial Information Technology, Fuzhou University, Fuzhou 350108, ChinaKey Laboratory of Spatial Data Mining and Information Sharing of Ministry of Education, National & Local Joint Engineering Research Centre of Satellite Geospatial Information Technology, Fuzhou University, Fuzhou 350108, ChinaJoint Institute for Coastal Research and Management, University of Delaware, Newark, DE 19716, USAKey Laboratory of Spatial Data Mining and Information Sharing of Ministry of Education, National & Local Joint Engineering Research Centre of Satellite Geospatial Information Technology, Fuzhou University, Fuzhou 350108, ChinaKey Laboratory of Spatial Data Mining and Information Sharing of Ministry of Education, National & Local Joint Engineering Research Centre of Satellite Geospatial Information Technology, Fuzhou University, Fuzhou 350108, ChinaJoint Institute for Coastal Research and Management, University of Delaware, Newark, DE 19716, USARetrieving information concerning the interior of the ocean using satellite remote sensing data has a major impact on studies of ocean dynamic and climate changes; however, the lack of information within the ocean limits such studies about the global ocean. In this paper, an artificial neural network, combined with satellite data and gridded Argo product, is used to estimate the ocean heat content (OHC) anomalies over four different depths down to 2000 m covering the near-global ocean, excluding the polar regions. Our method allows for the temporal hindcast of the OHC to other periods beyond the 2005–2018 training period. By applying an ensemble technique, the hindcasting uncertainty could also be estimated by using different 9-year periods for training and then calculating the standard deviation across six ensemble members. This new OHC product is called the Ocean Projection and Extension neural Network (OPEN) product. The accuracy of the product is accessed using the coefficient of determination (R<sup>2</sup>) and the relative root-mean-square error (RRMSE). The feature combinations and network architecture are optimized via a series of experiments. Overall, intercomparison with several routinely analyzed OHC products shows that the OPEN OHC has an R<sup>2</sup> larger than 0.95 and an RRMSE of <0.20 and presents notably accurate trends and variabilities. The OPEN product can therefore provide a valuable complement for studies of global climate changes.https://www.mdpi.com/2072-4292/12/14/2294remote sensing retrievalartificial neural networkocean heat contentdeep ocean remote sensing
spellingShingle Hua Su
Haojie Zhang
Xupu Geng
Tian Qin
Wenfang Lu
Xiao-Hai Yan
OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data
Remote Sensing
remote sensing retrieval
artificial neural network
ocean heat content
deep ocean remote sensing
title OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data
title_full OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data
title_fullStr OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data
title_full_unstemmed OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data
title_short OPEN: A New Estimation of Global Ocean Heat Content for Upper 2000 Meters from Remote Sensing Data
title_sort open a new estimation of global ocean heat content for upper 2000 meters from remote sensing data
topic remote sensing retrieval
artificial neural network
ocean heat content
deep ocean remote sensing
url https://www.mdpi.com/2072-4292/12/14/2294
work_keys_str_mv AT huasu openanewestimationofglobaloceanheatcontentforupper2000metersfromremotesensingdata
AT haojiezhang openanewestimationofglobaloceanheatcontentforupper2000metersfromremotesensingdata
AT xupugeng openanewestimationofglobaloceanheatcontentforupper2000metersfromremotesensingdata
AT tianqin openanewestimationofglobaloceanheatcontentforupper2000metersfromremotesensingdata
AT wenfanglu openanewestimationofglobaloceanheatcontentforupper2000metersfromremotesensingdata
AT xiaohaiyan openanewestimationofglobaloceanheatcontentforupper2000metersfromremotesensingdata