{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2024,9,2]],"date-time":"2024-09-02T13:09:04Z","timestamp":1725282544785},"reference-count":48,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2024,1,5]],"date-time":"2024-01-05T00:00:00Z","timestamp":1704412800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union"},{"DOI":"10.13039\/501100000844","name":"European Space Agency","doi-asserted-by":"publisher","award":["4000129892\/20\/NL\/FF\/ab"],"id":[{"id":"10.13039\/501100000844","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Institute of Geographic and Forest Information"},{"name":"CNES"},{"name":"Mission Performance Cluster of Sentinel-3"},{"name":"IsardSat, Catalonia","award":["4000111597\/14\/I-AM"]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"Two microwave transponders have been operating in west Crete and Gavdos to calibrate international satellite radar altimeters at the Ku-band. One has been continuously operating for about 8 years at the CDN1 Cal\/Val site in the mountains of Crete, and the other at the GVD1 Cal\/Val site on Gavdos since 11 October 2021. This ground infrastructure is also supported at present by four sea-surface Cal\/Val sites operating, some of them for over 20 years, while two additional such Cal\/Val sites are under construction. This ground infrastructure is part of the European Space Agency Permanent Facility for Altimetry Calibration (PFAC), and as of 2015, it has been producing continuously a time series of range biases for Sentinel-3A, Sentinel-3B, Sentinel-6 MF, Jason-2, Jason-3, and CryoSat-2. This work presents a thorough examination of the transponder Cal\/Val responses to understand and determine absolute biases for all satellite altimeters overflying this ground infrastructure. The latest calibration results for the Jason-3, Copernicus Sentinel-3A and -3B, Sentinel-6 MF, and CryoSat-2 radar altimeters are described based on four sea-surface and two transponder Cal\/Val sites of the PFAC in west Crete, Greece. Absolute biases for Jason-3, Sentinel-6 MF, Sentinel-3A, Sentinel-3B, and CryoSat-2 are close to a few mm, determined using various techniques, infrastructure, and settings.<\/jats:p>","DOI":"10.3390\/rs16020223","type":"journal-article","created":{"date-parts":[[2024,1,5]],"date-time":"2024-01-05T15:06:43Z","timestamp":1704467203000},"page":"223","source":"Crossref","is-referenced-by-count":2,"title":["The ESA Permanent Facility for Altimetry Calibration in Crete: Advanced Services and the Latest Cal\/Val Results"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"http:\/\/orcid.org\/0000-0002-1037-7376","authenticated-orcid":false,"given":"Stelios P.","family":"Mertikas","sequence":"first","affiliation":[{"name":"Geodesy and Geomatics Engineering Laboratory, Technical University of Crete, GR 73100 Chania, Greece"}]},{"given":"Craig","family":"Donlon","sequence":"additional","affiliation":[{"name":"European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Keplerlaan 1, AZ 2201 Noordwijk, The Netherlands"}]},{"given":"Costas","family":"Kokolakis","sequence":"additional","affiliation":[{"name":"Geodesy and Geomatics Engineering Laboratory, Technical University of Crete, GR 73100 Chania, Greece"},{"name":"Space Geomatica P.C., Xanthoudidou 10A, GR 73132 Chania, Greece"}]},{"ORCID":"http:\/\/orcid.org\/0000-0003-0148-8063","authenticated-orcid":false,"given":"Dimitrios","family":"Piretzidis","sequence":"additional","affiliation":[{"name":"Space Geomatica P.C., Xanthoudidou 10A, GR 73132 Chania, Greece"}]},{"ORCID":"http:\/\/orcid.org\/0000-0002-1886-0186","authenticated-orcid":false,"given":"Robert","family":"Cullen","sequence":"additional","affiliation":[{"name":"European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Keplerlaan 1, AZ 2201 Noordwijk, The Netherlands"}]},{"given":"Pierre","family":"F\u00e9m\u00e9nias","sequence":"additional","affiliation":[{"name":"European Space Research Institute (ESRIN), European Space Agency (ESA), Largo Galileo Galilei, I 00044 Frascati, Italy"}]},{"given":"Marco","family":"Fornari","sequence":"additional","affiliation":[{"name":"European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Keplerlaan 1, AZ 2201 Noordwijk, The Netherlands"}]},{"given":"Xenophon","family":"Frantzis","sequence":"additional","affiliation":[{"name":"Geodesy and Geomatics Engineering Laboratory, Technical University of Crete, GR 73100 Chania, Greece"}]},{"given":"Achilles","family":"Tripolitsiotis","sequence":"additional","affiliation":[{"name":"Space Geomatica P.C., Xanthoudidou 10A, GR 73132 Chania, Greece"}]},{"ORCID":"http:\/\/orcid.org\/0000-0002-3534-4554","authenticated-orcid":false,"given":"J\u00e9r\u00f4me","family":"Bouffard","sequence":"additional","affiliation":[{"name":"European Space Research Institute (ESRIN), European Space Agency (ESA), Largo Galileo Galilei, I 00044 Frascati, Italy"}]},{"ORCID":"http:\/\/orcid.org\/0000-0001-9727-4902","authenticated-orcid":false,"given":"Alessandro","family":"Di Bella","sequence":"additional","affiliation":[{"name":"European Space Research Institute (ESRIN), European Space Agency (ESA), Largo Galileo Galilei, I 00044 Frascati, Italy"}]},{"ORCID":"http:\/\/orcid.org\/0000-0003-1925-1558","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Boy","sequence":"additional","affiliation":[{"name":"Centre National d\u2019Etudes Spatiales (CNES), 31401 Toulouse, France"}]},{"ORCID":"http:\/\/orcid.org\/0000-0002-8154-8267","authenticated-orcid":false,"given":"Jerome","family":"Saunier","sequence":"additional","affiliation":[{"name":"R\u00e9seaux et Services en G\u00e9od\u00e9sie Spatiale, Service de G\u00e9od\u00e9sie et de M\u00e9trologie, Institut National de L\u2019information G\u00e9ographique et Foresti\u00e8re (IGN), 94165 Saint-Mande, France"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,5]]},"reference":[{"key":"ref_1","unstructured":"International Altimetry Team (2021). Altimetry for the future: Building on 25 years of progress. Adv. Space Res., 68, 319\u2013363."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4496","DOI":"10.1080\/01431161.2020.1718240","article-title":"Towards a European Cal\/Val service for earth observation","volume":"41","author":"Sterckx","year":"2020","journal-title":"Int. J. Remote Sens."},{"key":"ref_3","unstructured":"Francis, C.R., Caporali, A., Cavaleri, L., Cenci, A., Ciotto, P., Ciraolo, L., Gurtner, W., Massmann, F.H., del Rosso, D., and Scharroo, R. (1993). The Calibration of the ERS-1 Radar Altimeter-The Venice Calibration Campaign, ESA\/ESTEC. ESA Report ER-RP-ESA-RA-0257 Issue 2.0."},{"key":"ref_4","first-page":"1589","article-title":"CryoSat-2 range, datation and interferometer calibration with Svalbard transponder","volume":"62","author":"Fornari","year":"2008","journal-title":"Adv. Space Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1161","DOI":"10.1016\/j.asr.2020.08.013","article-title":"A brief history of the harvest experiment: 1989-2019","volume":"68","author":"Haines","year":"2020","journal-title":"Adv. Space Res."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1171","DOI":"10.1016\/j.asr.2019.09.049","article-title":"Corsica: A 20-Yr multi-mission absolute altimeter calibration site","volume":"68","author":"Bonnefond","year":"2020","journal-title":"Adv. Space Res."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1080\/01490419.2011.584834","article-title":"Absolute Calibration in Bass Strait, Australia: TOPEX, Jason-1 and OSTM\/Jason-2","volume":"34","author":"Watson","year":"2011","journal-title":"Mar. Geod."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Mertikas, S.P., Donlon, C., F\u00e9m\u00e9nias, P., Mavrocordatos, C., Galanakis, D., Tripolitsiotis, A., Frantzis, X., Tziavos, I.N., Vergos, G., and Guinle, T. (2018). Fifteen Years of Cal\/Val Service to Reference Altimetry Missions: Calibration of Satellite Altimetry at the Permanent Facilities in Gavdos and Crete, Greece. Remote Sens., 10.","DOI":"10.3390\/rs10101557"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1007\/s13131-021-1745-y","article-title":"Preliminary calibration results of the HY-2B altimeter\u2019s SSH at China\u2019s Wanshan calibration site","volume":"40","author":"Chen","year":"2021","journal-title":"Acta Oceanol. Sin."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Yang, L., Xu, Y., Zhou, X., Zhu, L., Jiang, Q., Sun, H., Chen, G., Wang, P., Mertikas, S.P., and Fu, Y. (2020). Calibration of an Airborne Interferometric Radar Altimeter over the Qingdao Coast Sea, China. Remote Sens., 12.","DOI":"10.3390\/rs12101651"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"232","DOI":"10.3389\/fmars.2019.00232","article-title":"Global Observations of Fine-Scale Ocean Surface Topography with the Surface Water and Ocean Topography (SWOT) Mission","volume":"6","author":"Morrow","year":"2019","journal-title":"Front. Mar. Sci."},{"key":"ref_12","first-page":"1","article-title":"Noumea: A new multi-mission Cal\/Val site for past and future altimetry missions?","volume":"2022","author":"Chupin","year":"2022","journal-title":"EGUsphere"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.rse.2011.07.024","article-title":"The Global Monitoring for Environment and Security (GMES) Sentinel-3 mission","volume":"120","author":"Donlon","year":"2012","journal-title":"Remote Sens. Environ."},{"key":"ref_14","first-page":"208","article-title":"Satellite Contributions to Climate Change Studies","volume":"161","author":"Parkinson","year":"2017","journal-title":"Proc. Am. Philos. Soc."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Mertikas, S.P., Tripolitsiotis, A., Donlon, C., Mavrocordatos, C., F\u00e9m\u00e9nias, P., Borde, F., Frantzis, X., Kokolakis, C., Guinle, T., and Vergos, G. (2020). The ESA Permanent Facility for Altimetry Calibration: Monitoring Performance of Radar Altimeters for Sentinel-3A, Sentinel-3B and Jason-3 using Transponder and Sea-Surface Calibrations with FRM Standards. Remote Sens., 12.","DOI":"10.3390\/rs12162642"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Mertikas, S.P., Donlon, C., Vuilleumier, P., Cullen, R., F\u00e9m\u00e9nias, P., and Tripolitsiotis, A. (2019). An Action Plan towards Fiducial Reference Measurements for Satellite Altimetry. Remote Sens., 11.","DOI":"10.3390\/rs11171993"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Goryl, P., Fox, N., Donlon, C., and Castracane, P. (2023). Fiducial Reference Measurements (FRMs): What Are They?. Remote Sens., 15.","DOI":"10.20944\/preprints202308.1421.v1"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Stammer, D., and Cazenave, A. (2017). Satellite Altimetry over Oceans and Lakes, CRC Press. [1st ed.].","DOI":"10.1201\/9781315151779"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Verron, J., Bonnefond, P., Aouf, L., Birol, F., Bhowrnic, S., Calmant, S., Conchy, T., Cr\u00e9taux, J.-F., Dibarboure, G., and Dubey, A.K. (2018). The benefits of the Ka-band as evidenced from the SARAL\/Altika altimetric mission: Sci-entific Applications. Remote Sens., 10.","DOI":"10.3390\/rs10020163"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Myasoedov, A., Johannessen, J.A., Kudryavtsev, V., Collard, F., and Chapron, B. (2012, January 1\u20133). Sun glitter as a \u201ctool\u201d for monitoring Ocean from Space. Proceedings of the 2nd International Conference on Remote Sensing, Enviornment and Transportation Engineering, Nanjing, China.","DOI":"10.1109\/RSETE.2012.6260759"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1007\/s10291-018-0744-8","article-title":"Software tools for GNSS interferometric reflectometry (GNSS-IR)","volume":"22","author":"Roesler","year":"2018","journal-title":"GPS Solut."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"3387","DOI":"10.1080\/01431161.2022.2091965","article-title":"Hourly sea level height forecast based on GNSS-IR using ARIMA model","volume":"43","author":"Zheng","year":"2022","journal-title":"Int. J. Remote Sens."},{"key":"ref_23","unstructured":"Chen, C., Desai, S., Picot, N., Fu, L.-L., Morrow, R., Pavelsky, T., and Cretaux, J.-F. (2022, August 05). SWOT Calibration\/Validation Plan, Available online: https:\/\/swot.jpl.nasa.gov\/system\/documents\/files\/2244_2244_D-75724_SWOT_Cal_Val_Plan_Initial_20180129u.pdf."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Mertikas, S.P., Partsinevelos, P., Tripolitsiotis, A., Kokolakis, C., Petrakis, G., and Frantzis, X. (2020). Validation of Sentinel-3 OLCI In-tegrated Water Vapor Products using regional GNSS measurements in Crete, Greece. Remote Sens., 12.","DOI":"10.3390\/rs12162606"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"112395","DOI":"10.1016\/j.rse.2021.112395","article-title":"The Copernicus Sentinel-6 mission: Enhanced continuity of satellite sea level measurements from space","volume":"258","author":"Donlon","year":"2021","journal-title":"Remote Sens. Environ."},{"key":"ref_26","unstructured":"Giulicchi, I., Tavernier, G., Picot, N., Cullen, R., Scharroo, R., Martin-Puig, C., Desai, S., Desjonquerres, J.D., Leuliette, E., and Egido, A. (2019). Sentinel-6\/Jason-CS Cal\/Val Concept, European Space Research and Technology Centre. Available online: https:\/\/shorturl.at\/jLWZ6."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1438","DOI":"10.1016\/j.asr.2012.08.006","article-title":"DORIS and GPS monitoring of the Gavdos calibration site in Crete","volume":"51","author":"Willis","year":"2013","journal-title":"Adv. Space Res."},{"key":"ref_28","unstructured":"Herring, T.A., King, R.W., and McClusky, S.C. (2020). GAMIT Reference Manual: GPS Analysis at MIT, Release 10.7, Massachusetts Institute of Technology."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1002\/j.2161-4296.2010.tb01772.x","article-title":"Undifferenced GPS ambiguity resolution using the decoupled clock model and ambiguity datum fixing","volume":"57","author":"Collins","year":"2010","journal-title":"Navigation"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2458","DOI":"10.1016\/j.asr.2022.07.001","article-title":"Performance evaluation of the CDN1 altimetry Cal\/Val transponder to internal and external constituents of uncertainty","volume":"70","author":"Mertikas","year":"2022","journal-title":"Adv. Space Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"221","DOI":"10.3989\/scimar.03618.18A","article-title":"Performance of modern tide gauges: Towards mm-level accuracy","volume":"76","author":"Testut","year":"2012","journal-title":"Sci. Mar."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1983","DOI":"10.1175\/JTECH-D-18-0235.1","article-title":"Assessment of tide gauge biases and precision by the combination of multiple collocated time series","volume":"36","author":"Gorbon","year":"2019","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1238","DOI":"10.1175\/2007JTECHO554.1","article-title":"The van de Casteele test revisited: An efficient approach to tide gauge error characterization","volume":"25","author":"Testut","year":"2008","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1080\/15210609409379734","article-title":"Description of accuracy using conventional and robust estimates of scale","volume":"17","author":"Mertikas","year":"1994","journal-title":"Mar. Geod."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1007\/s00190-020-01398-0","article-title":"The combined global gravity field model XGM2019e","volume":"94","author":"Zingerle","year":"2020","journal-title":"J. Geod."},{"key":"ref_36","unstructured":"F\u00f6rste, C., Bruinsma, S., Flechtner, F., Abrykosov, O., Dahle, C., Marty, J., Lemoine, J., Biancale, R., Barthelmes, F., and Neumayer, K. (2014). GFZ Data Services, GFZ German Research Centre for Geosciences."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1007\/s11200-015-1114-4","article-title":"GECO: A global gravity model by locally combining GOCE data and EGM2008","volume":"60","author":"Gilardoni","year":"2016","journal-title":"Stud. Geophys. Geod."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Thibaut, P., Piras, F., Roinard, H., Guerou, A., Boy, F., Maraldi, C., Bignalet-Cazalet, F., Dibarboure, G., and Picot, N. (2021, January 11\u201316). Benefits of the adaptive retracking solution for the Jason-3 GDR-F reprocessing campaign. Proceedings of the 2021 IEEE International Geoscience and Remote Sensing Symposium, Brussels, Belgium.","DOI":"10.1109\/IGARSS47720.2021.9553647"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/1345_2019_56","article-title":"Fiducial Reference Measurements for Satellite Altimetry Calibration: The Constituents","volume":"Volume 150","author":"Mertikas","year":"2019","journal-title":"Fiducial Reference Measurements for Altimetry"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Mertikas, S.P., Lin, M., Piretzidis, D., Kokolakis, C., Donlon, C., Ma, C., Zhang, Y., Jia, Y., Mu, B., and Frantzis, X. (2023). Absolute Calibration of the Chinese HY-2B Altimetric Mission with Fiducial Reference Measurement Standards. Remote Sens., 15.","DOI":"10.3390\/rs15051393"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Andersen, O.B., Zhang, S., Sandwell, D.T., Dibarboure, G., Smith, W.H.F., and Abulatijiang, A. (2021). The Unique Role of the Jason Ge-odetic Missions for high Resolution Gravity Field and Mean Sea Surface Modelling. Remote Sens., 13.","DOI":"10.3390\/rs13040646"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Cullen, R., Donlon, C., Fornari, M., and Giulicchi, L. (2022, January 17\u201322). Sentinel-6 Michael Freilich Poseidon-4 Altimeter In-Orbit Performance. Proceedings of the GARSS 2022-2022 IEEE International Geoscience and Remote Sensing Symposium, IEEE, Kuala Lumpur, Malaysia.","DOI":"10.1109\/IGARSS46834.2022.9883552"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1418","DOI":"10.1016\/j.asr.2012.10.021","article-title":"Altimetry, bathymetry and geoid variations at the Gavdos permanent Cal\/Val facility","volume":"51","author":"Mertikas","year":"2013","journal-title":"Adv. Space Res."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Kokolakis, C., Piretzidis, D., and Mertikas, S.P. (2022). Impact of Satellite Attitude on Altimetry Calibration with Microwave Transponders. Remote Sens., 14.","DOI":"10.3390\/rs14246369"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Naeije, M., Di Bella, A., Geminale, T., and Visser, P. (2023). CryoSat Long-Term Ocean Data Analysis and Validation: Final Words on GOP Baseline-C. Remote Sens., 15.","DOI":"10.3390\/rs15225420"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"841","DOI":"10.1016\/j.asr.2005.07.027","article-title":"CryoSat: A mission to determine the fluctuations in Earth\u2019s land and marine ice fields","volume":"37","author":"Windham","year":"2006","journal-title":"Adv. Space Res."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"3776","DOI":"10.1109\/TGRS.2020.3022522","article-title":"Multi-peak Retracking of CryoSat-2 SARIn Waveforms Over Arctic Sea Ice","volume":"59","author":"Kwok","year":"2021","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Mertikas, S.P., and Pail., R. (2020). Fiducial Reference Measurements for Altimetry, Springer International Publishing.","DOI":"10.1007\/978-3-030-39438-7"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/2\/223\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,9]],"date-time":"2024-01-09T09:14:52Z","timestamp":1704791692000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/16\/2\/223"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,1,5]]},"references-count":48,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["rs16020223"],"URL":"https:\/\/doi.org\/10.3390\/rs16020223","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,1,5]]}}}