1. Laser Telescope Laser wavelength532 nm Laser energy per pulse50-80 uJ Laser pulse repetition freq.>100 Hz Detector Photoncounting Scattered Light Ocean Lidar Development Beam-c M. Behrenfeld, J. Rall, C. Koblinsky, et al Remote sensing of upper ocean physical and biological properties

2. Science Objectives Ocean circulation and ecosystem response Physical Oceanography –Mixed Layer depth critical variable in ocean- atmosphere coupling. Ocean biology and carbon –Mixing depth key to understanding upper ocean productivity.

3. 2001 Progress Oregon State Univ. develop advanced ray tracing model funded by NASA HQ Ocean program DDF and IR&D support development of “bench lidar” system for laboratory validation of fundamental ray tracing model. GSFC ocean biogeochemistry laboratory starts photo-acclimation experiments. GSFC ISAL study of advanced Mixed Layer Lidar concept for aircraft. Mixed layer modeling post-doc hired. TRL 1 seeks to become TRL 2-3.

4. Particulate Carbon Total Particulate Scattering Satellites now provide global surface chlorophyll concentrations Photosynthesis per unit chlorophyll varies primarily with mixed layer light levels and in proportion to algal carbon to chlorophyll ratios Algal carbon concentration is highly correlated with particulate attenuation or scattering Particulate scattering or attenuation can potentially be measured actively or passively from space Ocean Productivity

5. Ocean Biogeochemistry Laboratory NASA GSFC, Building 22 Photo acclimation in 23 algal species Chlorophyll : Photosynthesis Growth Irradiance Laboratory Focus: Characterizing the effects of light and nutrient stress on the ratio chlorophyll to photosynthetic carbon fixation

6. Requirement: Remote Sensing: Cloud-corrected Irradiance Light Attenuation Mixed Layer Depth SeaWiFS/MODIS data Light Model SeaWiFS/MODIS data Ocean Optical Model Wind Stress (QuikScat) Direct Measurement? Modeling Photoacclimation

7. Technology Development Lead: Jonathan Rall/Code 924 Microchip laser (1-2 uJ/pulse at 532 nm 2-3 kHz pulse repetition rate), photon counting detectors. –Controlled experiments at David Taylor Model Basin for transmission, reflection, scattering, and refraction effects of incident laser pulse with wavey surface. –Test GSFC and OSU ray-trace models. Ship board lidar (30-40 uJ/pulse at 532nm) for open ocean demonstration later this year.

8. Challenges Link between scattering layer and mixed layer depth. Lidar remote sensing for ocean biology. Quantification of the ray tracing model with hardware. Identify candidate lidar concepts and technologies.

9. Summary Slide

10. Ocean Lidar Development Mike Behrenfeld, Chet Koblinsky, Code 971, Jonathan Rall, Code 924 Lidar remote sensing of upper ocean mixing and biology -Air-sea exchange & climate -Ocean productivity & carbon -TRL 1 moving toward TRL 2-3 2001 Activities New Ocean Biogeochemistry Lab in Bldg 22 begins photoacclimation experiments. IRD, DDF laser development Ray tracing model improvement ISAL study of future aircraft system Challenges Link between scattering and mixed layers – ray tracing model. Quantify model with laser system. Implications for biology. Identify candidate lidar concepts and technologies.