The ONR-sponsored Radiance in a Dynamic Ocean (RaDyO), which was initiated in 2005, is a 5-year project devoted to the topic of light propagation and imaging across the air-sea interface and within the ocean's surface boundary layer (SBL) as affected by the physics and chemistry of the upper ocean and atmospheric forcing. Modeling, application of emergent technologies, and field experiments are being used for RaDyO studies. Three Field Experiments are included: Scripps Pier Experiment (instrument testing in nearshore conditions, January 6-28, 2008), Benign conditions (Santa Barbara Channel moderate wind conditions, September 7-28, 2008), and High Sea State conditions (south of the Big Island of Hawaii, planned for August 23-September 14, 2009).

The primary goals of the ONR-sponsored Radiance in a Dynamic Ocean (RaDyO) program are to:
(1) Examine time-dependent oceanic radiance distribution in relation to dynamic surface boundary layer (SBL) processes.
(2) Construct a radiance-based SBL model.
(3) Validate the model with field observations.
(4) Investigate the feasibility of inverting the model to yield SBL conditions.

The questions to be answered by the RaDyO program are thus twofold:

(1) Time-Averaged Case:

  • How does μ change as a function of optical depth?
  • How does degree of polarization change as a function of optical depth?
  • Do SBL conditions affect these relationships? If so, how?
  • What is the optimum L(θ,φ) measurement resolution as a function of optical depth?

    (2) Time-Dependent Case:
  • What are the relevant SBL processes that affect L(θ,φ) as a function of Δt and ΔΩ?
  • Are the effects of SBL processes unique?
  • At what level of complexity can we realistically validate a SBL model?

    The images and reconstructions (below) were made available by Arete Associates, and provide an illustrative motivation for the RaDyO program. The feasibility of constructing ocean surface estimates using underwater camera data has been demonstrated. However, wave estimates are not yet accurate enough to substantially improve the reconstructed images above the surface beyond what can be achieved assuming a flat surface. RaDyO investigators are collecting a broad suite of relevant physical and optical data on exceptionally short time and space scales.

    motivation motivation motivation motivation

    Objects in a scene taken from underwater are naturally blurred by wave motion. The image in column two was sharpened, resulting in a clearer picture. Column three shows shots that were remapped to angular coordinates near the horizon. This technique can be used in combination with an improved wave estimation algorithm, i.e. the two techniques are independent of one another.

    See full list of Investigators for additional contact information.

    Steve Ackleson, ONR E-mail: Ackleson
    Tommy Dickey, OPL/UCSB E-mail: Dickey

    Guide to the RaDyO Website

    The RaDyO website is designed to provide quick access to information about the project. Below are brief descriptions of materials found under the banner headings:

    Investigators - Provides lists of RaDyO Program Managers, RaDyO ONR-Funded Participants, and RaDyO Collaborators with key contact information.

    News and Notes - Is used to give useful information for the project including logistics for upcoming experiments and RaDyO-related news items.

    Meetings - Summarizes the locations and dates of RaDyO workshops and meetings. Agendas, reports, and Power Point presentations for several of the meetings and workshops may be accessed by clicking on the blue check marks.

    Field Experiments - Information concerning each of the three field experiments is provided. The subheadings are 1) Scripps Pier Experiment, 2) Benign Conditions for the Santa Barbara Channel Experiment, and 3) High Sea-State Conditions for the Hawaii Experiment. Included are dates of the experiments, calendars for deployments during the experiments, maps for the experiments, platform pictures and lists of personnel on each platform, tables with measurements by platform and with responsible investigators, and useful information concerning complementary data sets.

    Data - Data are largely accessible from individual investigators or their ftp or websites. Brief descriptions of data availability are given. Please see Tables in Field Experiments section for each experiment with investigators responsible for specific measurements.

    FTP Site - The RaDyO ftp site contains a large number of folders and files that are applicable to the project. Some of the information is contained on the present website; however, some of the larger files are not. For example preliminary Santa Barbara Channel data reports and photographs taken during the Santa Barbara Channel field experiment are kept here. A guide to the information on the ftp site is shown by clicking on this header.

    Publications - Under this header you will find some Key References and Websites for the Santa Barbara Channel RaDyO Experiment and the Hawaii RaDyO Experiment. In addition, there are potential papers based on measurements made during the Santa Barbara Channel RaDyO Experiment 2008 and previously published RaDyO papers.

    Photos - A guide to accessing photographs taken during the various RaDyO field experiments.