Rodríguez
Ernesto
Rodríguez
Ernesto
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ArticleA Ka-band wind Geophysical Model Function using doppler scatterometer measurements from the Air-Sea Interaction Tower experiment(MDPI, 2022-04-26) Polverari, Federica ; Wineteer, Alexander ; Rodríguez, Ernesto ; Perkovic-Martin, Dragana ; Siqueira, Paul ; Farrar, J. Thomas ; Adam, Max ; Closa Tarrés, Marc ; Edson, James B.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.
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ArticleThe winds and currents mission concept(Frontiers Media, 2019-07-24) Rodríguez, Ernesto ; Bourassa, Mark A. ; Chelton, Dudley B. ; Farrar, J. Thomas ; Long, David ; Perkovic-Martin, Dragana ; Samelson, Roger M.The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches.
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ArticleIntegrated observations of global surface winds, currents, and waves: Requirements and challenges for the next decade(Frontiers Media, 2019-07-24) Villas Bôas, Ana B. ; Ardhuin, Fabrice ; Ayet, Alex ; Bourassa, Mark A. ; Brandt, Peter ; Chapron, Bertrand ; Cornuelle, Bruce D. ; Farrar, J. Thomas ; Fewings, Melanie R. ; Fox-Kemper, Baylor ; Gille, Sarah T. ; Gommenginger, Christine ; Heimbach, Patrick ; Hell, Momme C. ; Li, Qing ; Mazloff, Matthew R. ; Merrifield, Sophia T. ; Mouche, Alexis ; Rio, Marie H. ; Rodriguez, Ernesto ; Shutler, Jamie D. ; Subramanian, Aneesh C. ; Terrill, Eric ; Tsamados, Michel ; Ubelmann, Clement ; van Sebille, ErikOcean surface winds, currents, and waves play a crucial role in exchanges of momentum, energy, heat, freshwater, gases, and other tracers between the ocean, atmosphere, and ice. Despite surface waves being strongly coupled to the upper ocean circulation and the overlying atmosphere, efforts to improve ocean, atmospheric, and wave observations and models have evolved somewhat independently. From an observational point of view, community efforts to bridge this gap have led to proposals for satellite Doppler oceanography mission concepts, which could provide unprecedented measurements of absolute surface velocity and directional wave spectrum at global scales. This paper reviews the present state of observations of surface winds, currents, and waves, and it outlines observational gaps that limit our current understanding of coupled processes that happen at the air-sea-ice interface. A significant challenge for the coming decade of wind, current, and wave observations will come in combining and interpreting measurements from (a) wave-buoys and high-frequency radars in coastal regions, (b) surface drifters and wave-enabled drifters in the open-ocean, marginal ice zones, and wave-current interaction “hot-spots,” and (c) simultaneous measurements of absolute surface currents, ocean surface wind vector, and directional wave spectrum from Doppler satellite sensors.