TY - JOUR
T1 - Using in situ airborne measurements to evaluate three cloud phase products derived from CALIPSO
AU - Cesana, G.
AU - Chepfer, H.
AU - Winker, D.
AU - Getzewich, B.
AU - Cai, X.
AU - Jourdan, O.
AU - Mioche, G.
AU - Okamoto, H.
AU - Hagihara, Y.
AU - Noel, V.
AU - Reverdy, M.
N1 - Funding Information:
This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. H. Okamoto and Y. Hagihara were supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan through a Grant-in-Aid for Scientific Research, Kiban A (25247078) and by the Japan Aerospace Exploration Agency for EarthCARE Research Announcement. CALIPSO-GOCCP observations (orbit and statistics files) were downloaded from the CFMIP-Obs website (http://climserv.ipsl.polytechni-que.fr/cfmip-obs/Calipso_goccp.html). CALIPSO-ST and CALIPSO-KU orbit files were provided by the Science Team and Kyushu University Team, respectively, and the statistics files were processed on the CLIMSERV/IPSL computing facility. We would like to thank Bryan Baum, the two anonymous reviewers, and the Editor for their useful comments that improved our manuscript. In particular, we thank the anonymous reviewer who took the time to list and fix grammar and spelling problems in the original manuscript.
Publisher Copyright:
© 2016. American Geophysical Union. All Rights Reserved.
PY - 2016
Y1 - 2016
N2 - We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high- and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures.
AB - We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high- and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures.
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U2 - 10.1002/2015JD024334
DO - 10.1002/2015JD024334
M3 - Article
AN - SCOPUS:84969959988
SN - 0148-0227
VL - 121
SP - 5788
EP - 5808
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
IS - 10
ER -