Validation of the multi-mission altimeter wave height data for the Baltic Sea region
We present a complete cross-validation of significant wave heights (SWH) extracted from altimetry data from all ten existing satellites with available in situ (buoy and echosounder) wave measurements for the Baltic Sea basin. The main purpose is to select an adequate altimetry data subset for a subs...
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| Format: | Article |
| Language: | English |
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Estonian Academy Publishers
2016-08-01
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| Series: | Estonian Journal of Earth Sciences |
| Subjects: | |
| Online Access: | http://www.kirj.ee/public/Estonian_Journal_of_Earth_Sciences/2016/issue_3/earth-2016-3-161-175.pdf |
| _version_ | 1818982843376730112 |
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| author | Nadezhda A. Kudryavtseva Tarmo Soomere |
| author_facet | Nadezhda A. Kudryavtseva Tarmo Soomere |
| author_sort | Nadezhda A. Kudryavtseva |
| collection | DOAJ |
| description | We present a complete cross-validation of significant wave heights (SWH) extracted from altimetry data from all ten existing satellites with available in situ (buoy and echosounder) wave measurements for the Baltic Sea basin. The main purpose is to select an adequate altimetry data subset for a subsequent evaluation of the wave climate. The satellite measurements with the backscatter coefficients > 13.5 cdb, errors in the SWH normalized standard deviation > 0.5 m and snapshots with centroids closer than 0.2° to the land are not reliable. The ice flag usually denotes the ice concentration of > 50%. The presence of ice affects the SWH data starting from concentrations 10%, but substantial effects are only evident for concentrations > 30%. The altimetry data selected based on these criteria have very good correspondence with in situ data, except for GEOSAT Phase 1 data (1985–1989) that could not be validated. The root-mean-square difference of altimetry and in situ data is in the range of 0.23–0.37, which is significant for the Baltic Sea, compared with an average wave height of ~ 1 m. The bias for CRYOSAT-2, ERS-2, JASON-1/2 and SARAL data is below 0.06 m. The ENVISAT, ERS-1, GEOSAT and TOPEX satellites revealed larger biases up to 0.23 m. The SWH time series from several satellite pairs (ENVISAT/JASON-1, SARAL/JASON-2, ERS-1/TOPEX) exhibit substantial mutual temporal drift and part of them evidently are not homogeneous in time. A new high-resolution SWH data set from the SARAL satellite reveals a very good correspondence with the in situ data and with the data stream from previous satellites. |
| first_indexed | 2024-12-20T17:53:39Z |
| format | Article |
| id | doaj.art-f203754b2d4d46dab9d67691c7a8ed75 |
| institution | Directory Open Access Journal |
| issn | 1736-4728 1736-7557 |
| language | English |
| last_indexed | 2024-12-20T17:53:39Z |
| publishDate | 2016-08-01 |
| publisher | Estonian Academy Publishers |
| record_format | Article |
| series | Estonian Journal of Earth Sciences |
| spelling | doaj.art-f203754b2d4d46dab9d67691c7a8ed752022-12-21T19:30:47ZengEstonian Academy PublishersEstonian Journal of Earth Sciences1736-47281736-75572016-08-0165316117510.3176/earth.2016.1310.3176/earth.2016.13Validation of the multi-mission altimeter wave height data for the Baltic Sea regionNadezhda A. Kudryavtseva0Tarmo Soomere1Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn, Estonia; nadia@ioc.eeInstitute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn, EstoniaWe present a complete cross-validation of significant wave heights (SWH) extracted from altimetry data from all ten existing satellites with available in situ (buoy and echosounder) wave measurements for the Baltic Sea basin. The main purpose is to select an adequate altimetry data subset for a subsequent evaluation of the wave climate. The satellite measurements with the backscatter coefficients > 13.5 cdb, errors in the SWH normalized standard deviation > 0.5 m and snapshots with centroids closer than 0.2° to the land are not reliable. The ice flag usually denotes the ice concentration of > 50%. The presence of ice affects the SWH data starting from concentrations 10%, but substantial effects are only evident for concentrations > 30%. The altimetry data selected based on these criteria have very good correspondence with in situ data, except for GEOSAT Phase 1 data (1985–1989) that could not be validated. The root-mean-square difference of altimetry and in situ data is in the range of 0.23–0.37, which is significant for the Baltic Sea, compared with an average wave height of ~ 1 m. The bias for CRYOSAT-2, ERS-2, JASON-1/2 and SARAL data is below 0.06 m. The ENVISAT, ERS-1, GEOSAT and TOPEX satellites revealed larger biases up to 0.23 m. The SWH time series from several satellite pairs (ENVISAT/JASON-1, SARAL/JASON-2, ERS-1/TOPEX) exhibit substantial mutual temporal drift and part of them evidently are not homogeneous in time. A new high-resolution SWH data set from the SARAL satellite reveals a very good correspondence with the in situ data and with the data stream from previous satellites.http://www.kirj.ee/public/Estonian_Journal_of_Earth_Sciences/2016/issue_3/earth-2016-3-161-175.pdfaltimetervalidationsignificant wave heightBaltic Seawave climateSARAL/AltiKa. |
| spellingShingle | Nadezhda A. Kudryavtseva Tarmo Soomere Validation of the multi-mission altimeter wave height data for the Baltic Sea region Estonian Journal of Earth Sciences altimeter validation significant wave height Baltic Sea wave climate SARAL/AltiKa. |
| title | Validation of the multi-mission altimeter wave height data for the Baltic Sea region |
| title_full | Validation of the multi-mission altimeter wave height data for the Baltic Sea region |
| title_fullStr | Validation of the multi-mission altimeter wave height data for the Baltic Sea region |
| title_full_unstemmed | Validation of the multi-mission altimeter wave height data for the Baltic Sea region |
| title_short | Validation of the multi-mission altimeter wave height data for the Baltic Sea region |
| title_sort | validation of the multi mission altimeter wave height data for the baltic sea region |
| topic | altimeter validation significant wave height Baltic Sea wave climate SARAL/AltiKa. |
| url | http://www.kirj.ee/public/Estonian_Journal_of_Earth_Sciences/2016/issue_3/earth-2016-3-161-175.pdf |
| work_keys_str_mv | AT nadezhdaakudryavtseva validationofthemultimissionaltimeterwaveheightdataforthebalticsearegion AT tarmosoomere validationofthemultimissionaltimeterwaveheightdataforthebalticsearegion |