*4.2.3. Taiz city*

Low visibility range in Fig. 25 extends from 0.05 to 4 km for Taiz city. Scattering coefficient at low visibility 0.05 km is 44.8, 43.8 and 37.6 km-1 for wavelengths of 780, 850 and 1550 nm, respectively. The scattering coefficient of 4 km low visibility is 0.7, 0.65 and 0.37 km-1 for wavelengths of 780, 850, and 1550 nm, respectively. Figure 26 shows that the atmospheric attenuation versus low visibility for Taiz city. At low visibility of 0.05 km, atmospheric attenuation is 194.4, 190.2 and 163.5 dB for wavelengths of 780, 850 and 1550 nm, respectively. For 4 km low visibility, the atmospheric attenuation is about 3.1, 2.8 and 1.6 dB for wavelengths of 780, 850 and 1550 nm, respectively. Table 10 shows the results of scattering coefficient and atmospheric attenuation at low visibility for Sana'a, Aden and Taiz Cities. The results show

**Figure 24.** Atmospheric attenuation (dB) versus low visibility (km) for Aden city.

*4.2.2. Aden city*

198 Contemporary Issues in Wireless Communications

*4.2.3. Taiz city*

wavelengths 780, 850, and 1550 nm, respectively.

**Figure 23.** Scattering coefficient (km-1) versus low visibility (km) for Aden city.

1.95, 1.8 and 0.94 dB for wavelengths of 780, 850 and 1550 nm, respectively.

Low visibility range in Fig. 23 extends from 0.05 to 6 km for Aden city. Scattering coefficient at low visibility 0.05 km is 44.8, 43.8 and 37.6 km-1 for wavelengths of 780, 850 and 1550 nm, respectively. The scattering coefficient of 6 km low visibility is 0.45, 0.41 and 0.22 km-1 for

Figure 24 shows that the atmospheric attenuation versus low visibility for Aden city. At low visibility of 0.05 km, atmospheric attenuation is 194.4, 190.2 and 163.5 dB for wavelengths 780, 850 and 1550 nm, respectively. For 6 km low visibility, the atmospheric attenuation is about

Low visibility range in Fig. 25 extends from 0.05 to 4 km for Taiz city. Scattering coefficient at low visibility 0.05 km is 44.8, 43.8 and 37.6 km-1 for wavelengths of 780, 850 and 1550 nm, respectively. The scattering coefficient of 4 km low visibility is 0.7, 0.65 and 0.37 km-1 for wavelengths of 780, 850, and 1550 nm, respectively. Figure 26 shows that the atmospheric attenuation versus low visibility for Taiz city. At low visibility of 0.05 km, atmospheric attenuation is 194.4, 190.2 and 163.5 dB for wavelengths of 780, 850 and 1550 nm, respectively. For 4 km low visibility, the atmospheric attenuation is about 3.1, 2.8 and 1.6 dB for wavelengths of 780, 850 and 1550 nm, respectively. Table 10 shows the results of scattering coefficient and atmospheric attenuation at low visibility for Sana'a, Aden and Taiz Cities. The results show that with increasing the wavelength, in consequence the scattering coefficient and atmospheric attenuation decreased for the three cases were studied in this paper.

**Figure 25.** Scattering coefficient (km−1) versus low versus low visibility (km) for Taiz city.

**Figure 26.** Atmospheric attenuation (dB) versus low visibility (km) for Taiz city.


**Table 10.** Results of scattering coefficient and atmospheric attenuation at low visibility for Sana'a, Aden and Taiz cities.
