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CHARACTERISTICS FOR OPTICAL PROPERTIES
OF BACKGROUND AEROSOLS, WATER, AND
DUST CLOUDS MEASURED BY USING
LIDAR OVER CHUNG-LI, TAIWAN
C. W. CHIANG
∗
,
†
,
‡
,S.K.DAS
†
andJ.B.NEE
†
∗
Research Center for Environmental Changes, Academia Sinica,
Nankang, Taiwan
†
Department of Physics, National Central University, Chungli, Taiwan
‡
cwchiang@alumni.ncu.edu.tw
Aerosol and cloud studies are important as they affect both the radiation
and the climate of the atmosphere. In this paper, we present and discuss the
correlation between the optical properties of aerosol and cloud (
<
3km above
ground level) over Chung-Li (24.58
◦
N, 121.10
◦
E). This study was carried out
by using ground-based lidar and
in situ
balloon measurements from 2002-2004.
Results show that there are differences in the properties of the aerosol and
cloud measurements in the spring season (March-May), which may be due to
the differences in transport sources and aerosol compositions. These facts are
supported by backward trajectories, radiosonde, and height distributions of
aerosol-cloud backscatter and depolarization ratio. For background aerosols,
the depolarization ratio shows a decreasing trend with increasing relative
humidity and the backward trajectories displayed the origin of air masses
concluding that the source is from the coastal industrial area of China.
Dust-clouds traced back from Northeast China in Spring are marked by
higher depolarization and backscatter ratios, which is also sensitive to relative
humidity. The statistical properties of water-clouds and dust-clouds were also
accounted for.
1. Introduction
Both aerosols and clouds, due to their influences on the environment and
climate are always interesting aspects for various purposes of atmospheric
studies. Aerosols have the potential to change the global climate because
of their direct radiative effects and indirect effects as cloud condensation
‡
Corresponding author.
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