Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data
| dc.contributor.author | Yaremchuk, Max | en |
| dc.contributor.author | Beattie, Christopher A. | en |
| dc.contributor.author | Panteleev, Gleb | en |
| dc.contributor.author | D’Addezio, Joseph | en |
| dc.date.accessioned | 2024-06-14T13:51:00Z | en |
| dc.date.available | 2024-06-14T13:51:00Z | en |
| dc.date.issued | 2024-05-29 | en |
| dc.date.updated | 2024-06-13T14:53:49Z | en |
| dc.description.abstract | The recently deployed Surface Water and Ocean Topography (SWOT) mission for the first time has observed the ocean surface at a spatial resolution of 1 km, thus giving an opportunity to directly monitor submesoscale sea surface height (SSH) variations that have a typical magnitude of a few centimeters. This progress comes at the expense of the necessity to take into account numerous uncertainties in calibration of the quality-controlled altimeter data. Of particular importance is the proper filtering of <i>spatially</i> correlated errors caused by the uncertainties in geometry and orientation of the on-board interferometer. These “systematic” errors dominate the SWOT error budget and are likely to have a notable signature in the SSH products available to the oceanographic community. In this study, we explore the utility of the block-circulant (BC) approximation of the SWOT precision matrix developed by the Jet Propulsion Laboratory for assessment of a mission’s accuracy, including the possible impact of the systematic errors on the assimilation of the wide-swath altimeter data into numerical models. It is found that BC approximation of the precision matrix has sufficient (90–99%) accuracy for a wide range of significant wave heights of the ocean surface, and, therefore, could potentially serve as an efficient preconditioner for data assimilation problems involving altimetry observations by space-borne interferometers. An extensive set of variational data assimilation (DA) experiments demonstrates that BC approximation provides more accurate SSH retrievals compared to approximations, assuming a spatially uncorrelated observation error field as is currently adopted in operational DA systems. | en |
| dc.description.version | Published version | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.citation | Yaremchuk, M.; Beattie, C.; Panteleev, G.; D’Addezio, J. Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data. Remote Sens. 2024, 16, 1954. | en |
| dc.identifier.doi | https://doi.org/10.3390/rs16111954 | en |
| dc.identifier.uri | https://hdl.handle.net/10919/119442 | en |
| dc.language.iso | en | en |
| dc.publisher | MDPI | en |
| dc.rights | Creative Commons Attribution 4.0 International | en |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | en |
| dc.subject | sea surface height | en |
| dc.subject | swath altimetry | en |
| dc.subject | Surface Water and Ocean Topography (SWOT) | en |
| dc.subject | error covariance | en |
| dc.subject | data assimilation | en |
| dc.title | Block-Circulant Approximation of the Precision Matrix for Assimilating SWOT Altimetry Data | en |
| dc.title.serial | Remote Sensing | en |
| dc.type | Article - Refereed | en |
| dc.type.dcmitype | Text | en |