Abstract:

Through the ground-based measurements of Aerosol Optical Thickness (AOT) at the Xiamen Sea from January 7,
2008 to April 30, 2009, we have obtained hourly variability, daily variability, and monthly variability of AOT. The results
show that the hourly variability and monthly variability of AOT change regularly, while the daily variability of AOT changes a
lot according to the weather condition. The values of AOT peak in spring and autumn. The average AOT in April is greater than 0.9
when the air is turbid, while the average AOT in June is less than 0.3 when the air is relative clean. The Angstrom parameter α reach-
es its lowest value in June and fluctuates around 1.21 in other months. The annual-mean value of Angstrom parameter β is 0.25. The
comparison of MODIS Level 2 AOD with these ground-based measurements shows that the monthly variability of AOT retrieved
from MODIS is basically consistent with the one from the ground-based observation at the Xiamen Sea.

Key words: aerosol optical thickness, daily variability, monthly variability