Hoareau, C., Keckhut, P., Noel, V., Chepfer, H., and Baray, J.-L. 2013: A decadal cirrus clouds climatology from ground-based and spaceborne lidars above south of France (43.9° N–5.7° E), Accepted to Atmos. Chem. Phys. (ACPD reference: vol. 13, 6379-6417, doi:10.5194/acpd-13-6379-2013)
This study provides an analysis of cirrus clouds properties at midlatitude in the southern part of France from ground-based and spaceborne lidars. A climatology of cirrus clouds properties and their evolution over more than 12 yr is presented and compared to other mid-latitude climatological studies. Cirrus clouds occur ~ 37% of the total observation time and remain quasi-constant across seasons with a variation within ~ 5% around the mean occurrence. Similar results are obtained from CALIOP and the ground-based lidar, with a mean difference in occurrence of ~ 5% between both instruments. From the ground-based lidar data, a slight decrease in occurrence of ~ 3% per decade is observed but found statistically insignificant. Based on a clustering analysis of cirrus cloud parameters, three distinct classes have been identified and investigations concerning their origin are discussed. Properties of these different classes are analysed, showing that thin cirrus in the upper troposphere represent ~ 50% of cloud cover detected in summer and fall, decreasing by 15–20% for other seasons.
Ceccaldi M., J. Delanoë, R. J. Hogan , N. Pounder , A. Protat , J. Pelon, 2013: From CloudSat-CALIPSO to Earth-Care : Evolution of the DARDAR cloud classication and its validation using airborne radar-lidar observations. J. Geophys. Res. 10.1002/jgrd.50579
This paper presents the implementation of a new version of the DARDAR (raDAR liDAR) classification derived from CloudSat and CALIPSO data. The resulting target classification called DARDAR v2 is compared to the first version called DARDAR v1. Overall DARDAR v1 reports more cloud or rain pixels than DARDAR v2. In the low troposphere this is because v1 detects too many liquid cloud pixels, and in the higher troposphere this is because v2 is more restrictive in lidar detection than v1. Nevertheless, the spatial distribution of different types of hydrometeors show similar patterns in both classifications. The French airborne RAdar -LIdar (RALI) platform carries a CloudSat/CALIPSO instrument configuration (Lidar at a wavelength of 532 nm and a 95GHz cloud radar), as well as an EarthCare instrument configuration (High Spectral Resolution Lidar at 355 nm and a 95 GHz Doppler cloud radar). It therefore represents an ideal go-between for A-Train and EarthCare. The DARDAR v2 classification algorithm is adapted to RALI data for A-Train overpasses during dedicated airborne field experiments using the lidar at 532 nm and the radar Doppler measurements. The results from the RALI classification are compared with the DARDAR v2 classification to identify where the classification should still be interpreted with caution. Finally the RALI classification algorithm with lidar at 532 nm is adapted to RALI with High Spectral Resolution lidar data at 355 nm in preparation for EarthCare.