{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:53:42Z","timestamp":1760147622694,"version":"build-2065373602"},"reference-count":44,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,2,20]],"date-time":"2023-02-20T00:00:00Z","timestamp":1676851200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"TU-DELFT","award":["4000134959\/21\/NL\/FF\/an","80NSSC20K0074"],"award-info":[{"award-number":["4000134959\/21\/NL\/FF\/an","80NSSC20K0074"]}]},{"name":"NASA","award":["4000134959\/21\/NL\/FF\/an","80NSSC20K0074"],"award-info":[{"award-number":["4000134959\/21\/NL\/FF\/an","80NSSC20K0074"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The Harmony satellite mission was recently approved as the next European Space Agency (ESA) Earth Explorer 10. The mission science objectives cover several applications related to solid earth, the cryosphere, upper-ocean dynamics and air\u2013sea interactions. The mission consists of a constellation of two satellites, flying with the Copernicus Sentinel 1 (C or D) spacecraft, each hosting a C-band receive-only radar and a thermal infrared (TIR) payload. From an ocean dynamics\/air\u2013sea interaction perspective, the mission will provide the unique opportunity to observe simultaneously the signature of submesoscale upper-ocean processes via synthetic aperture radar and TIR imagery. The TIR imager is based on microbolometer technology and its acquisitions will rely on four channels: three narrow-band channels yielding observations at a \u22431 km spatial sampling distance (SSD) and a panchromatic (PAN, 8\u201312 \u03bcm) channel characterized by a \u2243300 m SSD. Our study investigates the potential of Harmony in retrieving spatial features related to sea surface temperature (SST) gradients from the high-resolution PAN channel, relying on top-of-atmosphere (TOA) observations. Compared to a standard SST gradient retrieval, our approach does not require atmospheric correction, thus avoiding uncertainties due to inter-channel co-registration and radiometric consistency, with the possibility of exploiting the higher resolution of the PAN channel. The investigations were carried out simulating the future Harmony TOA radiances (TARs), as well as relying on existing state-of-the-art level 1 satellite products. Our approach enables the correct description of SST features at the sea surface avoiding the generation of spurious features due to atmospheric correction and\/or instrumental issues. In addition, analyses based on existing satellite products suggest that the clear-sky TOA observations, in a typical mid-latitude scene, allow the reconstruction of up to 85% of the gradient magnitudes found at the sea-surface level. The methodology is less efficient in tropical areas, suffering from smoothing effects due to the high concentrations of water vapor.<\/jats:p>","DOI":"10.3390\/rs15041163","type":"journal-article","created":{"date-parts":[[2023,2,21]],"date-time":"2023-02-21T01:39:28Z","timestamp":1676943568000},"page":"1163","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Sea Surface Temperature Gradients Estimation Using Top-of-Atmosphere Observations from the ESA Earth Explorer 10 Harmony Mission: Preliminary Studies"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8767-4379","authenticated-orcid":false,"given":"Daniele","family":"Ciani","sequence":"first","affiliation":[{"name":"Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6428-217X","authenticated-orcid":false,"given":"Mattia","family":"Sabatini","sequence":"additional","affiliation":[{"name":"Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3416-7189","authenticated-orcid":false,"given":"Bruno","family":"Buongiorno Nardelli","sequence":"additional","affiliation":[{"name":"Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, 80133 Naples, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paco","family":"Lopez Dekker","sequence":"additional","affiliation":[{"name":"Department of Geoscience and Remote Sensing, Technische Universiteit Delft, 2628 Delft, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bj\u00f6rn","family":"Rommen","sequence":"additional","affiliation":[{"name":"European Space Research and Technology Center, European Space Agency, 2201 Noordwijk, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2549-1606","authenticated-orcid":false,"given":"David S.","family":"Wethey","sequence":"additional","affiliation":[{"name":"Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chunxue","family":"Yang","sequence":"additional","affiliation":[{"name":"Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1906-5248","authenticated-orcid":false,"given":"Gian Luigi","family":"Liberti","sequence":"additional","affiliation":[{"name":"Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1016\/j.dsr2.2013.12.001","article-title":"A comparison of satellite-derived sea surface temperature fronts using two edge detection algorithms","volume":"119","author":"Chang","year":"2015","journal-title":"Deep Sea Res. 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