The Alaska North Slope tracer study1 (see Figure 1) involved 44 hours of buoyant SF$ releases from a 39-in high turbine stack. Tracer sampler coverage ranged over seven arcs from 50 to 3000 m downwind.
Meteorological data, including wind speed, wind direction, temperature, sigma-theta and sigma-w, were available from an on-site tower at the 33-m level. Atmospheric stability and wind speed profiles were influenced by the smooth snow-covered tundra surface with negligible levels of solar radiation in the autumn months.
All experiments (44 usable hours) were conducted during the abbreviated day light hours (0900-1600). Wind speeds taken at the 33-m level during the tests were less than 6 m/s during one and part of another test, between 6 and 15 m/s during four tests, and in excess of 15 m/s during three tests.
The observed data were collected over 7 days: 23rd and 29th September 1987, 1st, 2nd, 4th, 7th, and 8th October 1987. Stability conditions were generally neutral or slightly stable.
The input data for the ADMS runs were taken from the AERMOD files downloaded from the United States Environmental Protection Agency website . These data included the arcwise maximum observed concentrations that have been used for comparison with the ADMS modelled concentrations.
This document compares the results of ADMS 220.127.116.11 (hereafter referred to as ADMS 4.1) with those of ADMS 18.104.22.168 (hereafter referred to as ADMS 4.2).