Quantifying and Understanding Atmospheric Turbulence Affecting Optical Propagation
Abstract
Quantifying and Understanding Atmospheric Turbulence Affecting Optical PropagationAbstract:One of the major efforts in high energy laser (HEL) research is on developing new atmospheric compensation techniques for beam control technology to maximize beam intensit"y in propagation. In such efforts, atmospheric optical turbulence conditions are simulated using a variety of techniques. It is thus" extremely important to characterize and model the atmosphericoptical turbulence to ensure that the technology developments are based on robust knowledge ofthe atmosphere effects.This task boils down to accurate characterization of the refractive index paramet"er, Cn2, one of the key factors affecting optical wave propagation in the atmosphere. Our knowledge on parameterization of Cn2 in th""e atmospheric surface layer, maritime or overland, is largely from the few field campaigns in horizontally homogeneous regions. As w"e are moving towards HighEnergy Laser (HEL) propagation in long distances and inevitably through turbulence field with varying unde"rlying surfaces, the current depictions of Cn2 in the atmosphere need to be modified to include its spatial and temporal variability" along the propagation path. The role of the meteorological forecast model also becomes increasingly important so that the atmospher"ic effect can be predicted. As such, we need to seek improved representations of Cn2 in terms of variables readily available from m"esoscale prediction models that provide the atmosphere~s general environment on the scale of ~100 km.We propose a collaborative project focusing on Cn2 in the atmospheric surface layer. We have designed a measurement and modeling program to address issues relate"d to the thrust area #4 (modeling the lower atmosphere) in the ONR Funding Opportunity Announcement (FOA, N00014-16-R-FO13). The pro""posed research is a combination of data collection, model simulation, and model evaluation and improvements effort. Our research wil""l focus on thecoastal region, due to its complexity in surface characteristics and the large range of boundarylayer conditions ass""ociated with coastal circulations, diurnal variations, and large-scale forcing.As such, long-term data collections augmented by int"ensive observations are needed to providegood sampling statistics as well as in-depth case analyses. The objective of the measurementprogram is to establish an optical turbulence data base by collecting a large number of coordinately sampled datasets in varying atmospheric forcing and surface conditions to support our proposed analyses as well as future research and development efforts related to atmospheric optical turbulence. Our measurements will be complemented with cutting edge fine-scale LargeEddy Simulation (LES) modeling capable of representing the complex coastal regions. Theobservational and modeling data will help us in the effort to evaluate and improve optical turbulence models for the lower atmosphere and develop the optical turbulence forecast capability in the Navy~s mesoscale forecast model.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712547
Entities
People
- Lian Shen
Organizations
- Office of Naval Research
- Regents of the University of Minnesota
- United States Navy