Validation of the Bulk Method for Overwater Optical Refractivity

Abstract

The effects of refraction on optical propagation at low altitudes over the ocean were investigated. A telescope was used to optically track ships to the range at which they disappeared over the horizon. Concurrent bulk meteorological measurements were used with surface-layer theory to model optical refractivity. A ray-trace program, with these profiles of refractivity, was used to calculate maximum intervision range (MIVR). Calculated MIVRs agree well with observations for subrefractive conditions (air cooler than water) typical of the open ocean. Agreement is not as good for super-refractive and ducting conditions (air warmer than water), which occurred with offshore flow and are therefore not typical of open ocean. Optical ducting conditions also appear to vary with range, such that point meteorological measurements and homogeneous ray tracing are not representative.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1991
Accession Number
ADA245029

Entities

People

  • R. A. Paulus

Tags

Communities of Interest

  • Ground and Sea Platforms
  • Sensors
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Temperature
  • Altitude
  • Boundary Layer
  • Coastal Regions
  • Corner Reflectors
  • Lapse Rate
  • Low Altitude
  • Low Elevation
  • Measurement
  • Mechanical Jamming
  • Meteorological Data
  • Meteorology
  • Observation
  • Offshore
  • Ray Tracing
  • Refraction
  • Validation

Fields of Study

  • Environmental science

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Optical Physics and Photonics.
  • Wave Propagation and Nonlinear Chaotic Dynamics.

Technology Areas

  • Space