EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Sabbah et al. 2001
Sabbah, I., Ichoku, C., Kaufman, Y.J. and Remer, L. (2001). Full year cycle of desert dust spectral optical thickness and precipitable water vapor over Alexandria, Egypt. Journal of Geophysical Research 106: doi: 10.1029/2000JD900410. issn: 0148-0227.

We study the annual cycle of dust loading in Alexandria, Egypt. Observations were performed from December 1997 to November 1998, including during the Kamaseen storms of March 1998. A ground-based, manual Sun photometer was used to measure aerosol optical thickness (&tgr;α) at four spectral bands in the 340--870 nm wavelength range (namely 340, 440, 675, 870). Total precipitable water vapor (W) was also measured simultaneously, based on the 936 nm channel measurements and extrapolations of the aerosol optical thickness from the neighboring 675 and 870 nm channels. Aerosol optical thickness &tgr;α at all the four spectral bands were very high (averaging 2.0--4.0) during the Kamaseen storms of late March 1998. Correspondingly, the ¿ngstr¿m wavelength exponent α of the optical thickness fell close to zero during that time, implying a substantial increase in dust. Overall, the monthly mean and median aerosol optical thickness were highest during January--May and lowest in June--October. During the January--May period total precipitable water vapor and ¿ngstr¿m exponent were lower than during the June--October period. There is a high correlation between the ¿ngstr¿m exponent and the optical thickness (r=0.63), with α ranging from 0.0 to 0.5 for &tgr;α > 1.0, indicating high dust concentration. Trajectory analysis shows that the presence of dust was associated with air masses arriving predominantly from the Sahara or North Africa. No significant correlation was found between the optical thickness and the precipitable water vapor. These basic systematic observations are vital for assessing dust climatology in this important part of the world and also for validating satellite observations and dust transport models. ¿ 2001 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Atmospheric Composition and Structure, Aerosols and particles (0345, 4801), Global Change, Atmosphere (0315, 0325), Global Change, Remote sensing, Oceanography, Biological and Chemical, Aerosols
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit