Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 16, 2341-2357, 2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
29 Feb 2016
CALIPSO climatological products: evaluation and suggestions from EARLINET
Nikolaos Papagiannopoulos1, Lucia Mona1, Lucas Alados-Arboledas2,3, Vassilis Amiridis4, Holger Baars5, Ioannis Binietoglou6, Daniele Bortoli7, Giuseppe D'Amico1, Aldo Giunta1, Juan Luis Guerrero-Rascado2,3, Anja Schwarz5, Sergio Pereira7, Nicola Spinelli8,9, Ulla Wandinger5, Xuan Wang8,10, and Gelsomina Pappalardo1 1Consiglio Nazionale delle Ricerche, Istituto di Metodologie per l'Analisi Ambientale (CNR-IMAA), C. da S. Loja, Tito Scalo (PZ), 85050, Italy
2Instituto Interuniversitario de Investigación del Sistema Tierra en Andalucía (IISTA-CEAMA), Av. del Mediterráneo, 18006, Granada, Spain
3Dpto. Física Aplicada, Universidad de Granada, Fuentenueva s/n, 18071, Granada, España
4IAASARS, National Observatory of Athens, Athens, Greece
5Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany
6National Institute of R&D for Optoelectronics (INOE), Magurele, Romania
7Earth Science Institute – (ICT), Évora, Portugal
8Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Naples Research Unit, Naples, Italy
9Dipartimento di Fisica, Università di Napoli Federico II, Naples, Italy
10Consiglio Nazionale delle Ricerche, Superconductors, oxides and other innovative materials and devices (CNR-SPIN), Naples, Italy
Abstract. The CALIPSO Level 3 (CL3) product is the most recent data set produced by the observations of the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument onboard the Cloud–Aerosol Lidar and Pathfinder Satellite Observations (CALIPSO) space platform. The European Aerosol Research Lidar Network (EARLINET), based mainly on multi-wavelength Raman lidar systems, is the most appropriate ground-based reference for CALIPSO calibration/validation studies on a continental scale. In this work, CALIPSO data are compared against EARLINET monthly averaged profiles obtained by measurements performed during CALIPSO overpasses. In order to mitigate uncertainties due to spatial and temporal differences, we reproduce a modified version of CL3 data starting from CALIPSO Level 2 (CL2) data. The spatial resolution is finer and nearly 2°  ×  2° (latitude  ×  longitude) and only simultaneous measurements are used for ease of comparison. The CALIPSO monthly mean profiles following this approach are called CALIPSO Level 3*, CL3*. We find good agreement on the aerosol extinction coefficient, yet in most of the cases a small CALIPSO underestimation is observed with an average bias of 0.02 km−1 up to 4 km and 0.003 km−1 higher above. In contrast to CL3 standard product, the CL3* data set offers the possibility to assess the CALIPSO performance also in terms of the particle backscatter coefficient keeping the same quality assurance criteria applied to extinction profiles. The mean relative difference in the comparison improved from 25 % for extinction to 18 % for backscatter, showing better performances of CALIPSO backscatter retrievals. Additionally, the aerosol typing comparison yielded a robust identification of dust and polluted dust. Moreover, the CALIPSO aerosol-type-dependent lidar ratio selection is assessed by means of EARLINET observations, so as to investigate the performance of the extinction retrievals. The aerosol types of dust, polluted dust, and clean continental showed noticeable discrepancy. Finally, the potential improvements of the lidar ratio assignment have been examined by adjusting it according to EARLINET-derived values.

Citation: Papagiannopoulos, N., Mona, L., Alados-Arboledas, L., Amiridis, V., Baars, H., Binietoglou, I., Bortoli, D., D'Amico, G., Giunta, A., Guerrero-Rascado, J. L., Schwarz, A., Pereira, S., Spinelli, N., Wandinger, U., Wang, X., and Pappalardo, G.: CALIPSO climatological products: evaluation and suggestions from EARLINET, Atmos. Chem. Phys., 16, 2341-2357,, 2016.
Publications Copernicus
Short summary
Satellite-derived products must undergo data evaluation with reference data sets in order to identify any possible reasons of discrepancy or to assess their representativity. In that direction, data coming from CALIPSO satellite were compared with observations from the ground. We identified a CALIPSO underestimation that could be linked to an assumption in the satellites' algorithms. The proposed correction improves the performance and could enhance aerosol modeling.
Satellite-derived products must undergo data evaluation with reference data sets in order to...