Objectives

  • Specify and understand how the natural variability of the atmosphere from minutes to days influences regional to long-range, low-frequency acoustic propagation.
  • Advance the fundamental understanding of acoustic propagation in the atmosphere.
  • Understand the influence of acoustic waves on the atmosphere and ionosphere.
  • Improve US national and international treaty organization capabilities to detect, locate, and characterize infrasound events of interest.

Approach

  • Collect all available contemporary lower-, middle-, and upper- atmospheric data (extensively from DoD, NOAA, NASA) to provide detailed time-dependent ground-to-space (0 to 180 km; G2S) atmospheric specifications for infrasound propagation calculations
  • Develop the next generation of normal mode, parabolic equation method, and Eikonal ray tracing acoustic wave propagation codes
  • Validate theoretical calculations utilizing both geophysical (e.g. earthquakes, tsunami, bolides, and volcanic eruptions), as well as manĀ·made infrasound sources (both planned and accidental)
  • Collaborate with other world experts to improve both automated and interactive infrasound network detection algorithms in order
    to reduce false alarm rates, lower detection thresholds, and improve source location estimate accuracies
  • Publish in archival journals as appropriate; more than 40 peer-reviewed papers, articles, and conference publications to date

Deliverable/Value/Accomplishment

  • NRL developed, maintains, and provides in near-real time, a continuous 10-year, 4x daily global G2S database; including ~3 years hourly at 13 x 13 km resolution over CONUS
  • Active participant in the planning of several recent high-profile national and international infrasound calculation experiments
  • NRL infrasound research partners include academia, industry, government, and international organizations