1. NAME AND TITLE

SPOOR: Monte Carlo Simulation of the Turbulent Transport of Airborne Contaminants.

2. CONTRIBUTOR

Los Alamos National Laboratory, Los Alamos, New Mexico.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; CDC 7600.

4. NATURE OF PROBLEM SOLVED

SPOOR solves the problem of atmospheric turbulent diffusion of a contaminant cloud in three dimensions with arbitrarily specified source configuration, turbulent-energy spectrum, and time-and-space-varying mean transport wind field.

5. METHOD OF SOLUTION

A Monte Carlo random-walk approach is used in which the contaminant cloud is represented as an ensemble of particles. The trajectory of each particle is simulated through a series of small time steps by taking into account the local mean wind, time-correlated velocity fluctuations, and random components to account for small-scale effects.

6. RESTRICTIONS OR LIMITATIONS

For SPOOR, the small-core memory is 49,000 and the large-core memory is 37,000. For the I/O Buffering Operations, the small-core memory is zero and the large-core memory is 350,000. There are no known restrictions on argument range.

7. TYPICAL RUNNING TIME

Running time (T) in seconds on the CDC 7600:

T = 22 + 0.0004 (N x M),

where N = number of time steps,

M = number of histories.

8. COMPUTER HARDWARE REQUIREMENTS

SPOOR was designed to run on a CDC 7600 computer.

9. COMPUTER SOFTWARE REQUIREMENTS

A FORTRAN IV compiler is required.

10. REFERENCE

C. W. Watson and S. Barr, "Monte Carlo Simulation of the Turbulent Transport of Airborne Contaminants," LA-6103 (January 1976).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code and sample problem input. A listing of the sample problem output is printed in the documentation.

12. DATE OF ABSTRACT

May 1976; revised March 1982, January 1983; reviewed February 1985.