Electro-optical (EO) and infrared (IR) signals propagating through the atmosphere exhibit intensity fluctuations caused by atmospheric turbulence, a phenomenon known as scintillation. Scintillation is directly related to the refractive index structure parameter Cn2 defined as the refractive index structure function scaled to for the turbulence inertial subrange. Quantifying Cn2 is essential to evaluate and predict scintillation effects on EO/IR systems. Meanwhile, aerosols in the lower atmosphere absorb and scatter EO/IR energy, resulting in attenuation, aliasing, and blurring.
We will present initial results on Cn2 and aerosol variability in the coastal zone using simultaneous measurements from a Twin Otter research aircraft, two instrumented ocean vessels [R/V John Martin and a rigid hull inflatable boat (RHIB)] , and a coastal land site. All measurements were taken as part of the Coastal Electro-Optical PropagaTion eXperiment (CEOPTeX) conducted in April/May 2016 offshore of Moss Landing, CA. Aerosol concentration, scattering, and absorption were obtained from the research aircraft in the atmospheric boundary layer. Cn2 was derived from measurements of temperature and humidity sampled at 20 Hz from all platforms/site. Two level Cn2 measurements were also taken when the R/V John Martin and the RHIB were co-located. We will discuss the spatial/temporal variability of the measured quantities, and the difference between the Cn2 at the coastal region and those predicted by surface layer similarity theory and the measured bulk quantities.
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