Wind rose

Since wind is circular, it is frequently easier to interpret and visualize the frequency of wind flow subjectively by displaying a wind rose, that is, wind frequencies for each direction oriented according to the azimuth for that direction. Figure 21-8 is a wind rose showing both directional frequencies and wind speed frequencies by six classes from 3-hourly observations for a 5-year period (1965-1969) for O Hare Airport, Chicago. The highest frequencies are from the south and west, the lowest from the southeast and east. 

Fig. 21-8. Wind rose (direction-speed) for O Hare Airport, Chicago, 1965-1969.

Figure 21-9 is a stability wind rose that indicates Pasquill stability class frequencies for each direction. For this location, the various stabilities seem to be nearly a set proportion of the frequency for that direction the larger the total frequency for that direction, the greater the frequency for each stability. Since the frequencies of A and B stabilities are quite small (0.72% for A and 4.92% for all three unstable classes (A, B, and C) are added together and indicated by the single line. 

One free software package worth downloading is WRPLOT View, which is a fully operational wind rose Windows program for your meteorological data. WRPLOT View is the logical replacement for the popular U.S. EPA DOS utility WRPLOT (this second program is also available at the site and is noted below). WRPLOT View s main features are ... 

Wind rose plots for wind speed and stability classes. 

Color wind rose and rain intensity plots. 

Prints wind rose plots or copy them for use in other applications. 

The calculation of atmospheric transport with its many parameters and frequency weighting of the wind rose is practical only with a computer code. Table 8.3-6... 

Wind rose A graphical method of showing the direction, velocity, and frequency of wind for a given location over set time periods. 

WRPLOT is an interactive program tliat generates wind rose statistics and plots for selected meteorological stations for user-specified date and time ranges. A wind rose depicts die frequency of occurrence of winds in each of 16 direction sectors (north, nordi-northcast, nordieast, etc.) and six wind speed classes for a given location and time period. 

Uniform wind rose rarely occurs Uniform ignition sources may be incorrect Single point source for all incidents may be inaccurate Assumplions to reduce the depth of treatment -... 

Weather conditions have a major effect on the mechanisms and extent a release spreads. Meteorological data are readily available from the National Oceanic and Atmosphere Administration (NOAA) and from airports in the vicinity of the facility. These data include wind direction, several wind speeds, and several atmospheric stability categories. A typical 16-point wind rose is... 

Wind rose—A plan view diagram that shows the percentage of time the wind is blowing in a particular direction. 

Source apportionment studies are frequently complemented by air mass origin analyses to identify where high pollution levels or certain compounds of interest come from. For small to meso scales this can be done by, e.g. wind rose analysis, whereas long-range transport is better assessed by using back trajectories calculated by a suitable dispersion model [20],... 

Assumption of symmetry - Unifonn wind rose rarely occurs... 

Fig. 2.5.9. A. Wind rose for area of Capricorn reefs weather.

Many features of atmospheric chemical transport can be inferred by inspection of the global-scale atmospheric circulation pattern. The west-to-east movement of industrial chemicals, such as acid rain precursors, is a familiar example in the midlatitudes of the Northern Hemisphere. Of course, these belts of wind, such as the midlatitude westerlies, are subject to modification on a smaller scale by a variety of local and regional conditions. For example, a wind rose from Chicago (Fig. 4-14) shows that despite the dominant southwesterly direction of the wind, wind from other directions also occurs. To explain such departures from the average global circulation pattern, atmospheric processes on smaller scales must be considered. 

FIGURE 4-14 A wind rose, which graphically portrays the statistical pattern of wind velocities (in knots) at O Hare Airport in Chicago from 1965 to 1969. Note the large fraction of time when winds are from the west to the south, as would be expected in the region of westerlies. At times, however, local and regional effects (e.g., storm systems) override the air movement attributable to global circulation (Boubel et ah, 1994). 

Figures. The wind roses in the days before May 17 1994 (a) and June 3 1994 (b).

The city of Veles, with its geographical position, atmospheric characteristics, urban and industrial concentration, and its improperly located the Lead and Zinc Smelter Plant upstream to the north wind opposite to the Wind Rose (north wind is dominant and dispersion of pollutants is going directly to the city), multiplied by inconvenient climate-meteorological, hydro-topographic factors has a huge and continuous air pollution problem. The Lead Smelter Plant, built in Veles in 1973, is located on the north of the city only 200-300 m away from first households. 

Wind Rose - A diagram that indicates the average percentage of time that the wind blows from different directions, on a monthly or annual basis. 

Between 1857 and 1864, Prestel (1865) systematically investigated the ozone concentration in Emden. Prestel s ozonometric wind rose we now call air pollution climatology. Prestel (1872) wrote that the determination of the periodic and unperiodic occurrence of ozone be a relevant moment for the climatology . 

Use a uniform wind rose (equal probability in all directions), unless certain wind directions are significantly different, sueb as in a deep valley. In this case, use of the local wind rose appropriate for each grouping of stability classes is recommended. 

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