HyCODEJan 2003 EcoLight: Irradiance calculations for coupled ecosystem models Curtis D. Mobley Sequoia Scientific, Inc. Bellevue, WA In collaboration with Paul Bissett Florida Environmental Research Institute Tampa, FL Work supported by U.S. Navy ONR HyCODE Program

HyCODEJan 2003 Science Goals Develop an extremely fast version of Hydrolight (EcoLight) for use in coupled physical-biological- optical ecosystem models [Status: done] Incorporate EcoLight into EcoSim as a called subroutine [Status: done] Quantify the improvements in ecosystem forecasts resulting from improved irradiance calculations [Status: underway]

The Big Picture EcoLight subroutine solves the RTE Regional Ocean Modeling System (ROMS) Ecosystem Model EcoSim Interface: converts EcoSim output to total IOPs component concentrations total IOP’s, etc. E o, E d, R rs light HyCODEJan 2003 Replaces simple E d model

HyCODEJan 2003 What’s new and great about this? For the first time ever, an ecosystem model has an accurate light field (computed from solving the RTE) under all conditions (case I or case II water; shallow, highly reflecting bottoms, etc.). All irradiances (E o, E d, E u ), mean cosines, and reflectances are available. The corresponding remote-sensing reflectance R rs is available for comparison with observation.

Note: the original ppt presentation links to a 15 Mbyte video clip here. Let me know if you want the video.

Note: the original ppt presentation links to a 15 Mbyte video clip here. Let me know if you want the video.

HyCODEJan 2003 Work for 2003 Continue on-going work with Bissett et al. doing quantitative evaluations of ecosystem simulations with the improved light calculations Final tweaking of code to find optimum balance between run time and accuracy, and to see how often EcoLight needs to be run Emphasis on LEO site Writing up the results

HyCODEJan 2003 Additional Work: Rippled Bottoms This figure shows that multiple scattering between ripple facets cannot be ignored when computing reflected radiances.

HyCODEJan 2003 Additional Work: Rippled Bottoms The Z&B reflectance correction factor must be replaced by a factor f that depends both on ripple geometry and material reflectance.

HyCODEJan 2003 Additional Work: Rippled Bottoms Bottom material reflectances used to simulate rippled bottoms for a bottom at 5 m depth and other conditions typical of LSI waters

HyCODEJan 2003 Additional Work: Rippled Bottoms Hydrolight with the Mobley reflectance correction factor agrees with the exact BMC3D results to within 3%, for LSI waters.

HyCODEJan 2003 Folks I need to talk to Bissett re the EcoSim-EcoLight papers Philpot and Boss re rippled-bottom papers Davis re LUT papers