The NASA-ISRO Synthetic Aperture Radar (NISAR) Mission experienced some technical issues in observatory level testing that required mitigations to be carried out on the reflector system, preventing a launch in 2024 as previously planned. The reflector has been reconditioned to address these issues, and NISAR is now on target for launch in early 2025. After launch, the spacecraft is planned to undergo commissioning for period of 90 days, after which science operations will begin. NISAR has two radar instruments - an L-band (24 cm wavelength) radar provided by NASA, and an S-band $(9.4 \\mathrm{~cm}$ wavelength) radar provided by ISRO - each of which can be operated individually or simultaneously. Each radar has a swath width of greater than 240 km for all modes at a variety of resolutions and polarimetric states. Due to precise orbit control and pointing, each radar also will produce repeat-pass interferometric measurements over all science targets. During the science phase, NISAR will collect about 35 Terabits of L-band radar image data each day, observing all land and ice-covered surfaces of Earth on the ascending and descending portions of each orbit every 12 days, and collecting about 5 Terabits of S-band radar image data each day over India and surrounding areas, Antarctica, and distributed global scientific areas of interest. Nearly all S- band acquisitions are collected simultaneously with L-band acquisitions, creating a unique globally distributed time- series data set. The commissioning plan calls for early engineering mode acquisitions around one month after launch, some of which may be usable to form images, followed by a period of orbit adjustment and system timing and pointing calibration. To prepare for science operations, the NISAR project has worked with the science team to develop a list of observational areas where early data can be acquired to demonstrate the preliminary quality of the data and to illustrate the science themes NISAR is addressing: solid Earth sciences, ecosystems sciences including global soil moisture, and cryosphere sciences, as well as many applications. In addition, cloud-based tools for image processing and diagnostic analysis, usable by the project and science team members alike, will be available to examine these early data sets.
", "doi": "10.1109/ingarss61818.2024.10984256", "isbn": "979-8-3503-9034-6", "publisher": "IEEE", "publication": "2024 IEEE India Geoscience and Remote Sensing Symposium (InGARSS)", "publication_date": "2024-12-02", "pages": "1-4" }, { "id": "authors:fqe6p-k0e46", "collection": "authors", "collection_id": "fqe6p-k0e46", "cite_using_url": "https://authors.library.caltech.edu/records/fqe6p-k0e46", "type": "conference_item", "title": "United States West Coast Surface Deformation with Wide-Swath L-Band ALOS-2 PALSAR-2 and NISAR", "author": [ { "family_name": "Belhadj-aissa", "given_name": "Saoussen", "orcid": "0000-0003-1376-4061" }, { "family_name": "Fielding", "given_name": "E.J.", "orcid": "0000-0002-6648-8067" }, { "family_name": "Liu", "given_name": "Z." }, { "family_name": "Tymofyeyeva", "given_name": "E.", "orcid": "0000-0001-5638-366X" }, { "family_name": "Havazli", "given_name": "E.", "orcid": "0000-0002-1236-7067" }, { "family_name": "Rosen", "given_name": "P.", "orcid": "0000-0002-4558-6004" }, { "family_name": "Simons", "given_name": "Mark", "orcid": "0000-0003-1412-6395", "clpid": "Simons-M" }, { "family_name": "Lindsay", "given_name": "D.", "orcid": "0009-0003-5119-6082" }, { "family_name": "B\u00fcrgmann", "given_name": "R.", "orcid": "0000-0002-3560-044X" }, { "family_name": "Bawden", "given_name": "G.W." } ], "abstract": "Launching in early 2024, the NASA-ISRO SAR (NISAR) mission will provide global data freely accessible enabling large scale surface deformation monitoring with synthetic aperture radar (SAR) acquired at L-band and S-band radar wavelengths. In preparation for calibration and validation of the NISAR L-band data, the NISAR Solid earth science team is systematically processing over 450 Japan Aerospace Exploration Agency (JAXA) ALOS-2 PalSAR-2 wide-swath (ScanSAR) L-band acquisitions covering the West Coast of the United States for measuring co-seismic, secular and transient displacements. The area spans California, Washington and Oregon.
", "doi": "10.1109/igarss53475.2024.10642177", "isbn": "979-8-3503-6032-5", "publisher": "IEEE", "publication": "IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium", "publication_date": "2024-07-07", "pages": "2434-2437" }, { "id": "authors:1vsd3-ate71", "collection": "authors", "collection_id": "1vsd3-ate71", "cite_using_url": "https://authors.library.caltech.edu/records/1vsd3-ate71", "type": "conference_item", "title": "Validation of NISAR Mission Requirements for Solid Earth Deformation Using GNSS", "author": [ { "family_name": "Borsa", "given_name": "A.", "orcid": "0000-0002-9939-1480" }, { "family_name": "Bekaert", "given_name": "D.", "orcid": "0000-0002-0408-0488" }, { "family_name": "Donnellan", "given_name": "A.", "orcid": "0000-0001-6843-8373" }, { "family_name": "Fielding", "given_name": "E. J.", "orcid": "0000-0002-6648-8067" }, { "family_name": "Lu", "given_name": "Z.", "orcid": "0000-0001-9181-1818" }, { "family_name": "Meyer", "given_name": "F.", "orcid": "0000-0002-2491-526X" }, { "family_name": "Rosen", "given_name": "P.", "orcid": "0000-0002-4558-6004" }, { "family_name": "Simons", "given_name": "M.", "orcid": "0000-0003-1412-6395", "clpid": "Simons-M" }, { "family_name": "Tymofyeyeva", "given_name": "E.", "orcid": "0000-0001-5638-366X" }, { "family_name": "Whetter", "given_name": "A." }, { "family_name": "Zebker", "given_name": "H.", "orcid": "0000-0001-9931-5237" }, { "family_name": "Zinke", "given_name": "R.", "orcid": "0000-0003-4174-3137" }, { "family_name": "Zwieback", "given_name": "S.", "orcid": "0000-0002-1398-6046" } ], "abstract": "We document one of several methodologies used to validate the NASA-ISRO Synthetic Aperture Radar (NISAR) mission requirements for solid earth deformation. NISAR's deformation requirements cover steady-state, coseismic, and transient deformation processes and were designed to confirm that the mission is able to meet its solid earth science goals. We use independent observations of earth surface deformation from continuous Global Navigation Satellite System (GNSS) stations as ground truth for NISAR-observed deformation, and we provide a statistical framework to assess the quality of the associated NISAR data products. Our validation workflows have been developed as Jupyter Notebooks and are publicly available via GitHub/GitLab.", "doi": "10.1109/igarss53475.2024.10642038", "isbn": "979-8-3503-6032-5", "publisher": "IEEE", "publication": "IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium", "publication_date": "2024-07-07", "pages": "6675-6677" }, { "id": "authors:y497f-c1k12", "collection": "authors", "collection_id": "y497f-c1k12", "cite_using_url": "https://authors.library.caltech.edu/records/y497f-c1k12", "type": "conference_item", "title": "Exploring the Dynamics of Antarctic ICE Streams and ICE Shelves Using Cosmo-Skymed", "author": [ { "family_name": "Simons", "given_name": "Mark", "orcid": "0000-0003-1412-6395", "clpid": "Simons-M" }, { "family_name": "Zhong", "given_name": "Minyan", "orcid": "0000-0002-1382-7061", "clpid": "Zhong-Minyan" }, { "family_name": "Minchew", "given_name": "Brent", "orcid": "0000-0002-5991-3926", "clpid": "Minchew-B-M" } ], "abstract": "We use repeat geodetic imaging of two major ice stream systems in Antarctica (Rutford and Evans Ice Streams) to explore the impact of large ocean tides under the Filchner-Ronne Ice Shelf on the dynamics of the ice shelf/ice stream system. We rely on dense time series of radar image acquisitions from multiple vantage points to construct the full 3D surface displacement time history over time scales of months to years. Our observations come from the COSMO-SkyMed constellation. For Evans Ice Stream, we also use observations from Sentinel lab. These time series allow us to evaluate rheological models of ice stream margins and to identify regions of ephemeral sub-shelf grounding. Understanding the sensitivity of such ephemeral pinning points to future thinning of the ice shelf can play an important role in forecasts of the rate of sea level rise over coming decades.", "doi": "10.1109/igarss46834.2022.9883808", "isbn": "978-1-6654-2792-0", "publisher": "IEEE", "publication": "2022 IEEE International Geoscience and Remote Sensing Symposium", "publication_date": "2022-07-17", "pages": "4750-4753" } ]