G. Vijayakumar et al., Aerosols in the atmospheric boundary layer and its association with surface wind speed at a coastal site, J ATMOS S-P, 60(16), 1998, pp. 1531-1542
Citations number
42
Categorie Soggetti
Earth Sciences
Journal title
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
A significant component of aerosol particles in the atmospheric boundary la
yer is contributed by surface wind. A simple exponential function or a powe
r-law is usually used to quantify this dependence. This is fairly valid ove
r oceans where the background component is rather small. But over the coast
, as a significant contribution to the background comes from the continent,
which may not have the same wind speed dependence, it may be physically mo
re meaningful to represent the aerosol system over the coast as the sum of
two components, one being the background and the other contributed by sea b
reeze. The wind speed dependence of aerosol scattering coefficient in the a
tmospheric boundary layer at a tropical coastal station is studied in the l
ight of the above hypothesis, using the data obtained from a bistatic conti
nuous wave lidar. The observed aerosol scattering coefficient at a fixed al
titude is represented as the sum of two components, one being the backgroun
d and the other depending on the current wind speed having a power-law type
wind dependence. The seasonal and altitude pattern of the two components a
re studied. It is seen that in this coastal site, during the monsoon season
, on average, approximately 25% of the mixing region aerosol optical depth
is contributed by the sea breeze. The seasonal pattern of the background co
mponent shows a marked difference within and above the a ell mixed region.
A comparison of mixing region aerosol optical depth has shown that similar
to 30% of the columnar aerosol optical depth comes from the lowest 1 km reg
ion of the atmosphere. (C) 1998 Elsevier Science Ltd. All rights reserved.