Impact of wind speed

Impact of wind speed parameters on the obtained results were analyzed on Case 1 model for different shape factor k values. Obtained results are given in Table 11 and Figure 4. 

Despite the central role that air-sea gas exchange plays in studies of marine productivity, biogeochemical cycles, atmospheric chemistry, and climate, it has proved extremely difficult to measure air-sea gas fluxes in situ. Only in 2001 were believable direct measurements of oceanic CO2 fluxes reported in the literature (McGillis et al., 2001a). In this section we examine the various models that have been proposed to understand the basic processes that control gas exchange mechanisms, describe results from laboratory experiments, and discuss the various techniques that have been developed to try to measure gas transfer rates in situ. Finally, we describe the development of wind speed (U) based para-metrizations and assess their impact on computation of air-sea gas fluxes. 

Post WW II concerns about the impact of mass fires led to studies in Europe and the United States of the physics and behavior of very large fires. A joint research effort called Project Flambeau by Australian, Canadian and United States foresters and civil defense agencies examined fire development over simulated urban regions in the late 1960s. They created simulated housing areas by creating 10 ft (2 m) high piles of pine and juniper wild-land fuels distributed in checkerboard patterns. Measurements were made of wind speeds, temperature, and fuel consumption rates. Fire whirls and fire tornadoes were observed to frequently occur [133,422],... 

Another important feature regarding rainfall is the effect of wind speed. Horizontal rain is often described, but in practice is unlikely to occur. However, wind speeds can give rain droplets significant horizontal components. The impact... 

The total 166 sets of experimental data are identified. The test results illustrate that short disturbances of wind speed, power and valve opening have no significant impact on natural circulation flow, implying that the system seems to tolerate these disturbances. A correlation of two-phase, natural circulation flow rate is derived from constitutive equations by use of lumped system parameters were obtained. The empirical coefficients m and n were obtained by non-linear regression of 83 test data. Compared with 166 sets of the measured data, the deviation of 98.8% of the data points is within 15%. 

Combinations of weather conditions, wind speed and wind direction along witli boiling point, vapor density, diffusivity, and heat of vaporization of tlie chemical released vary the healtli impact of tlie released chemical on the nearby population. To model a runaway reaction, the release of 10,000 gallons was assumed to occur over a 15-minute period. Tlie concentration of the chemical released was estimated, using procedures described in Part III (Chapter 12) for each combination of weather condition, wind speed, and wind direction. The results, combined with population data for tlie area adjacent to tlie plant, led to probability estimates of the number of people affected. Table 21.5.3 sunimarizes tlie findings. 

Researchers should be aware of, and account for, factors that can affect the performance of field studies with respect to precision, bias and possible error influences. The major factors affecting collectors, tracers and analytical approaches have been discussed elsewhere in this article. In summary, these are collection efficiency, stability and detection levels, respectively. Collection efficiency (or impaction parameter) for field samplers is related fo parficle/collector diameter and wind speed relationships, as summarized by the following equation developed by May and Clifford ... 

In the following chapter model refinements are described and compared with the setup used by Gughelmo (2008). The focus is given on the represention of marine organic matter. In a sensitivity study the impact of organic matter on long-range transport is explored. Additionally, a study is included that clarifies the relative importance of sea surface temperature, wind speed, and pollutant concentration for volatilisation of DDT from the ocean. 

Table 4.5 Impact pressures of average raindrops at various wind speeds...

Wind speed (km h ) Impact pressure of average raindrop of 0.5 g mass (cm head of water)... 

Step 2 required identification of source impacts by airshed modeling. Wind speed, direction, mixing height, and emission data bases designed to represent conditions on PACS sampling days were used to insure that the CMB impact estimates could be directly compared to model predictions for each sampllne site. 

If this excess absorption by clouds is ultimately shown to be a real phenomenon, then an increased cloud formation and extent due to anthropogenic emissions may alter the radiative balance of the atmosphere not only through increased reflectance but also through increased absorption of solar radiation. Such an effect could impact atmospheric temperatures, their vertical distribution, and circulation, as well as surface wind speeds and the surface latent heat flux (Kiehl et al., 1995). Hence establishing if this is truly excess absorption, and if so, its origins, is a critical issue that remains to be resolved. 

The characteristic lengths of the leaves were 23 mm (nettle), 28 mm (white poplar), and 27 mm (beech). Using these values of L, the wind speed (2.5 ms-1) and the diffusivities as given in Table 6.1, the values of Sh can be calculated and the results are plotted in Fig. 6.1. Also shown are results of Belot (1975), who exposed oak leaves and pine needles to an aerosol of 0.17 m diameter uranine particles in a wind tunnel, and used the fluorescence of the dye to measure the deposition. The points from Belot s experiments and those of Little Wiffen he fairly close to the theoretical line, with the exception of the results of 0.2- m lead aerosol to nettle and white poplar. These latter show enhanced deposition, probably due to impaction on, or interception by, the hairs on the leaves. 

Thus Sto is proportional to the wind speed, the density of the particle and the square of its diameter, and inversely proportional to the size of the obstacle. Both vv and Sto are functions of dA, and aerodynamic diameter is used to classify particles deposited by impaction or sedimentation. 

A Lycopodium spore, or pollen grain of similar size, has an energy of 1(T4 ergs (10-11 J) in a wind speed of 0.75 m s-1, which is typical of conditions near the top of crop canopies or in open woodland. Hence it is likely that pollen grains will bounce off dry leaves or stems, but will be trapped on the stigma of flowers, which are sticky. Spores of plant pathogens, however, are usually themselves moist or sticky, enabling them to adhere to leaves on impact. 

Plant pathologists need to study the dispersion of spores in the field. To avoid the need for a power supply, and the difficulties of arranging isokinetic samplers, passive samplers are often used (Gregory, 1973). Horizontal microscope slides are used to collect spores by sedimentation and vertical cylinders are used to collect them by impaction. The efficiency of captures by the cylinders depends on the wind speed, and requires calibration in the wind tunnel. 

Figures 6.7 and 6.8 are taken from Jann (1989) and were prepared to assess quickly the impact of various outside challenges on safe time by selecting the appropriate infiltration rate or air changes per hour (ACH) for the haven, and safe inside concentration. It must be noted that wind speed has not been accounted for in these curves. Higher wind speeds will cause high ACH for most buildings, thereby reducing the safe time for the haven.

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