Comparison of the CALIPSO satellite and ground-based observations of cirrus clouds at the ARM Tropical Western Pacific (TWP) sites

A reliable data set of cirrus cloud properties is necessary in order to quantify cloud radiative effects in the tropical tropopause layer (TTL). Thin cirrus clouds occur frequently in the TTL region, and their optical depths are commonly below the minimum detectable threshold of imaging radiometers and radars. Therefore, lidar observations are required to obtain a complete set of TTL cirrus cloud properties. In the TWP, we have two lidar options for observing the region: the ground-based ARM micropulse lidar (MPL) and the CALIOP instrument on board the CALIPSO satellite. Data sets from the ground-based MPL at the ARM TWP sites Manus, Nauru, and Darwin and data sets from the CALIPSO satellite are examined for consistency in ice and TTL cloud properties. Included in our comparison are cloud top and base heights, cloud thickness, number of cloud layers per profile, and optical depth. We will explore potential causes of the noted discrepancies between the two data sets.