Aquarius - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Aquarius

The Experts below are selected from a list of 4017 Experts worldwide ranked by ideXlab platform

Emmanuel P. Dinnat – 1st expert on this subject based on the ideXlab platform

  • IGARSS – Sea Surface Salinity Retrievals from Aquarius Using Neural Networks
    IGARSS 2019 – 2019 IEEE International Geoscience and Remote Sensing Symposium, 2019
    Co-Authors: Yan Soldo, David M. Le Vine, Emmanuel P. Dinnat

    Abstract:

    Even though the Sea Surface Salinity (SSS) retrieved from Aquarius are generally very close to in-situ measurements, the level of similarity varies with the region and with the circumstances of the observations (wind speed, sea surface temperature, etc.). SSS is currently retrieved from the brightness temperatures measured by Aquarius and applying the current theoretical model for the propagation and emission of the natural thermal radiation. In this contribution we consider an alternative retrieval approach based on a Neural Network (NN) with the goal of improving the subsets of Aquarius SSS data that are in poorer agreement with in-situ measurements. The subset considered here are the SSS retrieved at latitudes higher than 30˚. The output of the NN approach are compared against in-situ measurements using four statistical metrics (correlation coefficient, bias, RMSD and 5% trimmed range). The output of the NN and the nominal Aquarius SSS are compared against SSS values from in-situ measurements and from ocean models. From these comparisons it appears that the output of the NN matches the in-situ measurements better than the nominal Aquarius SSS.

  • Status of Aquarius and Salinity Continuity
    Remote Sensing, 2018
    Co-Authors: David M. Le Vine, Frank J. Wentz, Thomas Meissner, Emmanuel P. Dinnat, Gary Lagerloef

    Abstract:

    Aquarius is an L-band radar/radiometer instrument combination that has been designed to measure ocean salinity. It was launched on 10 June 2011 as part of the Aquarius/SAC-D observatory. The observatory is a partnership between the United States National Aeronautics and Space Agency (NASA), which provided Aquarius, and the Argentinian space agency, Comisiόn Nacional de Actividades Espaciales (CONAE), which provided the spacecraft bus, Satelite de Aplicaciones Cientificas (SAC-D). The observatory was lost four years later on 7 June 2015 when a failure in the power distribution network resulted in the loss of control of the spacecraft. The Aquarius Mission formally ended on 31 December 2017. The last major milestone was the release of the final version of the salinity retrieval (Version 5). Version 5 meets the mission requirements for accuracy, and reflects the continuing progress and understanding developed by the science team over the lifetime of the mission. Further progress is possible, and several issues remained unresolved at the end of the mission that are relevant to future salinity retrievals. The understanding developed with Aquarius is being transferred to radiometer observations over the ocean from NASA’s Soil Moisture Active Passive (SMAP) satellite, and salinity from SMAP with accuracy approaching that of Aquarius are already being produced.

  • Aquarius Final Release Product and Full Range Calibration of L-Band Radiometers
    IGARSS 2018 – 2018 IEEE International Geoscience and Remote Sensing Symposium, 2018
    Co-Authors: Emmanuel P. Dinnat, David Le Vine, Liang Hong

    Abstract:

    Aquarius final product V5.0 has been released. The dataset includes close to four years of global radiometric measurements at L-band. The mission’s objective was to monitor sea surface salinity, but other applications of its data over land and the cryosphere have been developed. For this reason, it is important to have accurate calibration over the full range of antenna temperatures from natural targets. It is also needed in order to combine Aquarius measurements with other L-band sensors. Aquarius calibration is strongly focused on the ocean. We present a research product which is part of the final release and aims at producing an accurate calibration from the low end (celestial sky) to the high end (land and ice) of the brightness temperature scale. We calibrate the Aquarius radiometers using measurements over the Sky and oceans and assess the new calibration using measurements over land.

P. De Matthaeis – 2nd expert on this subject based on the ideXlab platform

  • Radio Frequency Interference (RFI) Products on the Aquarius Website
    IGARSS 2018 – 2018 IEEE International Geoscience and Remote Sensing Symposium, 2018
    Co-Authors: P. De Matthaeis, D. Le M. Vine, Y. Soida, V. Tsontos

    Abstract:

    Aquarius has produced maps of salinity by measuring Earth’s natural emissions at L-band. However, measurements made by its instruments are affected by the presence of Radio Frequency Interference (RFI). For this reason, RFI detection algorithms had been implemented, both for the radiometer and the scatterometer, in order to reduce the impact of RFI on science data. In an effort to improve understanding of L-band RFI, the Aquarius mission has generated a new series of products. This contribution presents how these products were produced as well as the information that they contain. These products will be available starting at the end of January 2018 on the Aquarius website.

  • IGARSS – Radio Frequency Interference (RFI) Products on the Aquarius Website
    IGARSS 2018 – 2018 IEEE International Geoscience and Remote Sensing Symposium, 2018
    Co-Authors: P. De Matthaeis, D.m. Le Vine, Y. Soida, V. Tsontos

    Abstract:

    Aquarius has produced maps of salinity by measuring Earth’s natural emissions at L-band. However, measurements made by its instruments are affected by the presence of Radio Frequency Interference (RFI). For this reason, RFI detection algorithms had been implemented, both for the radiometer and the scatterometer, in order to reduce the impact of RFI on science data. In an effort to improve understanding of L-band RFI, the Aquarius mission has generated a new series of products. This contribution presents how these products were produced as well as the information that they contain. These products will be available starting at the end of January 2018 on the Aquarius website.

  • Aquarius status and recent results
    Radio Science, 2014
    Co-Authors: D. Le M. Vine, P. De Matthaeis, S. Abraham, G.s.e Lagerloef, Emmanuel P. Dinnat, C. Utku

    Abstract:

    Aquarius is a combination active/passive instrument at L band designed to map sea surface salinity globally from space. The radiometer (passive) is the primary instrument for retrieving salinity, and the scatterometer (active) provides information to correct for a major source of error, sea surface roughness (waves). In addition, the radiometer includes a number of special features designed to meet the goal for this challenging measurement, including measurement of the third Stokes parameter to help with the correction for Faraday rotation and rapid sampling to help with the mitigation of radio frequency interference. Aquarius was launched on 10 June 2011 aboard the Aquarius/SAC-D observatory and has been working well. The salinity retrieval continues to improve, and the special features suggest the potential for new applications of remote sensing from space at L band.

Gary Lagerloef – 3rd expert on this subject based on the ideXlab platform

  • Status of Aquarius and Salinity Continuity
    Remote Sensing, 2018
    Co-Authors: David M. Le Vine, Frank J. Wentz, Thomas Meissner, Emmanuel P. Dinnat, Gary Lagerloef

    Abstract:

    Aquarius is an L-band radar/radiometer instrument combination that has been designed to measure ocean salinity. It was launched on 10 June 2011 as part of the Aquarius/SAC-D observatory. The observatory is a partnership between the United States National Aeronautics and Space Agency (NASA), which provided Aquarius, and the Argentinian space agency, Comisiόn Nacional de Actividades Espaciales (CONAE), which provided the spacecraft bus, Satelite de Aplicaciones Cientificas (SAC-D). The observatory was lost four years later on 7 June 2015 when a failure in the power distribution network resulted in the loss of control of the spacecraft. The Aquarius Mission formally ended on 31 December 2017. The last major milestone was the release of the final version of the salinity retrieval (Version 5). Version 5 meets the mission requirements for accuracy, and reflects the continuing progress and understanding developed by the science team over the lifetime of the mission. Further progress is possible, and several issues remained unresolved at the end of the mission that are relevant to future salinity retrievals. The understanding developed with Aquarius is being transferred to radiometer observations over the ocean from NASA’s Soil Moisture Active Passive (SMAP) satellite, and salinity from SMAP with accuracy approaching that of Aquarius are already being produced.

  • Assessment of Aquarius Sea Surface Salinity
    Remote Sensing, 2018
    Co-Authors: Gary Lagerloef, Oleg Melnichenko, Thomas Meissner, Peter Hacker

    Abstract:

    Aquarius was the first NASA satellite to observe the sea surface salinity (SSS) over the global ocean. The mission successfully collected data from 25 August 2011 to 7 June 2015. The Aquarius project released its final version (Version-5) of the SSS data product in December 2017. The purpose of this paper is to summarize the validation results from the Aquarius Validation Data System (AVDS) and other statistical methods, and to provide a general view of the Aquarius SSS quality to the users. The results demonstrate that Aquarius has met the mission target measurement accuracy requirement of 0.2 psu on monthly averages on 150 km scale. From the triple point analysis using Aquarius, in situ field and Hybrid Coordinate Ocean Model (HYCOM) products, the root mean square errors of Aquarius Level-2 and Level-3 data are estimated to be 0.17 psu and 0.13 psu, respectively. It is important that caution should be exercised when using Aquarius salinity data in areas with high radio frequency interference (RFI) and heavy rainfall, close to the coast lines where leakage of land signals may significantly affect the quality of the SSS data, and at high-latitude oceans where the L-band radiometer has poor sensitivity to SSS.

  • Status of Aquarius Salinity
    2018 IEEE 15th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad), 2018
    Co-Authors: David Le Vine, Gary Lagerloef, Thomas Meissner, Emmanuel P. Dinnat, Liang Hong, Frank J. Wentz

    Abstract:

    Aquarius, an L-band radar/radiometer instrument combination designed to measure ocean salinity. It was launched June 10, 2011 as part of the Aquarius/SAC-D observatory, a partnership between NASA, which provided Aquarius, and the Argentine space agency (CONAE) which provided the spacecraft bus, SAC-D. The observatory was lost four years later on June 7, 2015 when a failure in the power distribution network resulted in loss of control of the spacecraft. The Aquarius Mission formally ended December 31, 2017. The last major milestone was the release of the Project’s final version of the salinity retrieval (Version 5.0). Version 5.0 meets the Mission requirements for accuracy and reflects the continuing progress and understanding developed by the Science Team over the lifetime of the mission.