Climatology analysis of Cirrus Cloud in 3 ARM Sites

Cirrus cloud play an important role in the atmospheric energy balance and hence in the earth’s climate system. The properties of optically thin clouds can be determined from measurements of transmission of the direct solar beam. The accuracy of cloud optical properties determined in this way is compromised by contamination of the direct transmission by light that is scattered into the sensors field of view. With the forward scattering correction method developed by Min et al., (2004), the accuracy of thin cloud retrievals from MFRSR has been improved. In this study, we do statistics studies on cirrus clouds properties based on multi-years cirrus cloud measurements from MFRSR at ARM sites and HUBC site. The site locations include mid-latitude, tropics and North-pole regions. Through the statistic studies, temporal and spatial variations of cirrus clouds are investigated.