An Extensive Analysis of Low-Level IR Transmission Measurements taken over a 15km Path during EOPACE with IRBLEM

Results of over 300 far IR and mid IR transmission measurements taken during several EOPACE intensive operational periods over the low-level 15 km transmission path across San Diego bay are presented. A thorough comparison with calculations obtained using simultaneously measured bulk meteorological parameters with the IR Boundary Layer Model, illustrate the effects that refractance, aerosol extinction and molecular extinction can have on the transmission. Discrepancies between the transmission measurements and the model's predictions are identified and investigated by varying various model parameters, and looking at available measured aerosol size distributions and refraction measurements over the path. Comparisons with the measured transmissions are reasonably good and show that the total measurements over the path. Comparison with the measured transmissions are reasonably good and show that the total transmission depends critically on all three effects, with the molecular transmittance depending upon the water vapor density and the characteristics of the IR source and detector, the aerosol transmittance upon the visibly, and the refractive effects on the stability of the marine boundary layer or the virtual potential air-sea temperature difference