A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment
Physical understanding and modeling of Ka-band ocean surface backscatter is challenging due to a lack of measurements. In the framework of the NASA Earth Ventures Suborbital-3 Submesoscale Ocean Dynamics Experiment (S-MODE) mission, a Ka-Band Ocean continuous wave Doppler Scatterometer (KaBODS) buil...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-04-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/9/2067 |
| _version_ | 1827671674720354304 |
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| author | Federica Polverari Alexander Wineteer Ernesto Rodríguez Dragana Perkovic-Martin Paul Siqueira J. Thomas Farrar Max Adam Marc Closa Tarrés James B. Edson |
| author_facet | Federica Polverari Alexander Wineteer Ernesto Rodríguez Dragana Perkovic-Martin Paul Siqueira J. Thomas Farrar Max Adam Marc Closa Tarrés James B. Edson |
| author_sort | Federica Polverari |
| collection | DOAJ |
| description | Physical understanding and modeling of Ka-band ocean surface backscatter is challenging due to a lack of measurements. In the framework of the NASA Earth Ventures Suborbital-3 Submesoscale Ocean Dynamics Experiment (S-MODE) mission, a Ka-Band Ocean continuous wave Doppler Scatterometer (KaBODS) built by the University of Massachusetts, Amherst (UMass) was installed on the Woods Hole Oceanographic Institution (WHOI) Air-Sea Interaction Tower. Together with ASIT anemometers, a new data set of Ka-band ocean surface backscatter measurements along with surface wind/wave and weather parameters was collected. In this work, we present the KaBODS instrument and an empirical Ka-band wind Geophysical Model Function (GMF), the so-called ASIT GMF, based on the KaBODS data collected over a period of three months, from October 2019 to January 2020, for incidence angles ranging between 40° and 68°. The ASIT GMF results are compared with an existing Ka-band wind GMF developed from data collected during a tower experiment conducted over the Black Sea. The two GMFs show differences in terms of wind speed and wind direction sensitivity. However, they are consistent in the values of the standard deviation of the model residuals. This suggests an intrinsic geophysical variability characterizing the Ka-band surface backscatter. The observed variability does not significantly change when filtering out swell-dominated data, indicating that the long-wave induced backscatter modulation is not the primary source of the KaBODS backscatter variability. We observe evidence of wave breaking events, which increase the skewness of the backscatter distribution in linear space, consistent with previous studies. Interestingly, a better agreement is seen between the GMFs and the actual data at an incidence angle of 60° for both GMFs, and the statistical analysis of the model residuals shows a reduced backscatter variability at this incidence angle. This study shows that the ASIT data set is a valuable reference for studies of Ka-band backscatter. Further investigations are on-going to fully characterize the observed variability and its implication in the wind GMF development. |
| first_indexed | 2024-03-10T03:45:11Z |
| format | Article |
| id | doaj.art-a941cc91eb334baca2ca2a3bbac70575 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T03:45:11Z |
| publishDate | 2022-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-a941cc91eb334baca2ca2a3bbac705752023-11-23T09:10:04ZengMDPI AGRemote Sensing2072-42922022-04-01149206710.3390/rs14092067A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower ExperimentFederica Polverari0Alexander Wineteer1Ernesto Rodríguez2Dragana Perkovic-Martin3Paul Siqueira4J. Thomas Farrar5Max Adam6Marc Closa Tarrés7James B. Edson8Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USAJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USAJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USAJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USAElectrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USAWoods Hole Oceanographic Institution, Woods Hole, MA 02543, USAElectrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USAElectrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USAWoods Hole Oceanographic Institution, Woods Hole, MA 02543, USAPhysical understanding and modeling of Ka-band ocean surface backscatter is challenging due to a lack of measurements. In the framework of the NASA Earth Ventures Suborbital-3 Submesoscale Ocean Dynamics Experiment (S-MODE) mission, a Ka-Band Ocean continuous wave Doppler Scatterometer (KaBODS) built by the University of Massachusetts, Amherst (UMass) was installed on the Woods Hole Oceanographic Institution (WHOI) Air-Sea Interaction Tower. Together with ASIT anemometers, a new data set of Ka-band ocean surface backscatter measurements along with surface wind/wave and weather parameters was collected. In this work, we present the KaBODS instrument and an empirical Ka-band wind Geophysical Model Function (GMF), the so-called ASIT GMF, based on the KaBODS data collected over a period of three months, from October 2019 to January 2020, for incidence angles ranging between 40° and 68°. The ASIT GMF results are compared with an existing Ka-band wind GMF developed from data collected during a tower experiment conducted over the Black Sea. The two GMFs show differences in terms of wind speed and wind direction sensitivity. However, they are consistent in the values of the standard deviation of the model residuals. This suggests an intrinsic geophysical variability characterizing the Ka-band surface backscatter. The observed variability does not significantly change when filtering out swell-dominated data, indicating that the long-wave induced backscatter modulation is not the primary source of the KaBODS backscatter variability. We observe evidence of wave breaking events, which increase the skewness of the backscatter distribution in linear space, consistent with previous studies. Interestingly, a better agreement is seen between the GMFs and the actual data at an incidence angle of 60° for both GMFs, and the statistical analysis of the model residuals shows a reduced backscatter variability at this incidence angle. This study shows that the ASIT data set is a valuable reference for studies of Ka-band backscatter. Further investigations are on-going to fully characterize the observed variability and its implication in the wind GMF development.https://www.mdpi.com/2072-4292/14/9/2067Ka-bandmodellingscatterometrysea surface backscattersurface windsvariability |
| spellingShingle | Federica Polverari Alexander Wineteer Ernesto Rodríguez Dragana Perkovic-Martin Paul Siqueira J. Thomas Farrar Max Adam Marc Closa Tarrés James B. Edson A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment Remote Sensing Ka-band modelling scatterometry sea surface backscatter surface winds variability |
| title | A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment |
| title_full | A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment |
| title_fullStr | A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment |
| title_full_unstemmed | A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment |
| title_short | A Ka-Band Wind Geophysical Model Function Using Doppler Scatterometer Measurements from the Air-Sea Interaction Tower Experiment |
| title_sort | ka band wind geophysical model function using doppler scatterometer measurements from the air sea interaction tower experiment |
| topic | Ka-band modelling scatterometry sea surface backscatter surface winds variability |
| url | https://www.mdpi.com/2072-4292/14/9/2067 |
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