Remote Sensing Climatology of Cirrus Cloud Distribution within the United States

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 using both active and passive instrument. We retrieve measurements of the direct solar beam transmittance from the MultiFilter Rotation Shadowband Radiometer (MFRSR). With CALIOP L2 cloud layer backscattering product, we were able to derive few thin cloud optical properties. The accuracy of cloud optical properties determined from MFRSR is compromised by contamination of the direct transmission by light that is scattered into the sensors field of view; which Min et al., 2004 developed an algorithm using forward scattering correction method to improve the accuracy of thin cloud retrievals from MFRSR. In this study, we do statistics studies on cirrus clouds properties based on multi-years cirrus cloud measurements from MFRSR and CALIPSO at few ARM sites and HUBC site. The site locations include South Great Plain, and North Slope of Alaska regions. Our result shows over 30% of cirrus cloud present in the atmosphere are within optical depth between (1-2). We also found the average seasonal variation of thin COD during summer is ~ 2. Through the statistic studies, temporal and spatial variations of cirrus clouds are investigated.