The Structure of Atmospheric Diffusion at Regional Scales
Abstract
The NOAA/ACURATE data, nineteen-month long series of 12-hour averaged Kr-85 air-concentration measurements at five sites up to 1050 km downwind of a source near AIKEN SC, are analyzed by a technique of fractal geometry, the renormalized-range statistic R/S. Fractional Brownian motion (Hurst) exponents H equal to about 0.35 are found for atmospheric eddy sizes of several hundred km, the enstrophy-cascade range, and these increased to H-values of about 0.45 for larger scale motions. Corresponding fractal dimensions, D, equal about 1.65 and 1.55. Related power spectra and auto-correlations are discussed. The fractal indices can be applied in numerical diffusion models using available computer algorithms. Examples of R/S-analysis of short-range, rapid-response atmospheric diffusion observations are compared with the ACURATE results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 31, 1991
- Accession Number
- ADA233153
Entities
People
- Franklin A. Gifford