On the physics of dusty atmospheres

✍ Scribed by M. G. El-Fandy

• Book ID: 104571441
• Publisher: John Wiley and Sons
• Year: 1953
• Tongue: English
• Weight: 264 KB
• Volume: 79
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49707934010

✦ Synopsis

Abstract

Measurements of particle size and concentration of atmospheric dust have been made at Alexandria in various degrees of turbidity. Except for ‘dust haze,’ reasonable agreement is obtained between the measurements and Koschmieder's equation for visibility in terms of optical attenuation. In ‘duststorms’ the required attenuation implies a scatter coefficient per particle 8/3 times the cross‐sectional area of the particles, while in occasions of ‘dust’ the scatter coefficient implied per particle is 4 times the cross‐sectional area of the particles. The results are as follows:

Dusty atmosphere	Visibility (m)	Average concentration (cm^−3^)	Average particle diameter (μ)	90% of particles have diameter ≤ (μ)	Scatter coefficient per particle/cross‐sectional area of particles
Dust haze	5,000–6,000	200	0.5	1.3
Dust	2,000–2,500	330	1.3	2.0	4
Duststorm	750–1,000	550	2.0	3.5	8/3