TY - JOUR
T1 - An Assessment of the Impacts of Cloud Vertical Heterogeneity on Global Ice Cloud Data Records From Passive Satellite Retrievals
AU - Wang, Chenxi
AU - Platnick, Steven
AU - Fauchez, Thomas
AU - Meyer, Kerry
AU - Zhang, Zhibo
AU - Iwabuchi, Hironobu
AU - Kahn, Brian H.
N1 - Funding Information:
The authors are grateful for support from the NASA Radiation Sciences Program. The computations in this study were performed at the UMBC High Performance Computing Facility (HPCF). The facility is supported by the U.S. National Science Foundation through the MRI program (grants CNS-0821258 and CNS-1228778) and the SCREMS program (grant DMS 0821311), with additional substantial support from UMBC. The Collection 6 MODIS products (doi: http://dx.doi.org/10.5067/MODIS/MYD06_L2.006) are publicly available from the NASA and Atmosphere Archive and Distribution System (LAADS, http://ladsweb.nascom.nasa.gov). The CloudSat/CALIPSO 2C-ICE (version 4; doi:10.1002/2015JD023600) products are publicly available from the CloudSat Data Processing Center (http://www.cloudsat.cira.colostate.edu/data-products). The instM_3d_asm_Np products (3D, monthly mean instantaneous, pressure-level, assimilated meteorological fields, version 5.12.4) are from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2; doi: 10.1175/JCLI-D-16-0758.1) and are publicly available from the NASA Goddard Earth Sciences (GES) Data and Information Services Center (https://disc.gsfc.nasa.gov/).
Funding Information:
The authors are grateful for support from the NASA Radiation Sciences Program. The computations in this study were performed at the UMBC High Performance Computing Facility (HPCF). The facility is supported by the U.S. National Science Foundation through the MRI program (grants CNS‐ 0821258 and CNS‐1228778) and the SCREMS program (grant DMS 0821311), with additional substantial support from UMBC. The Collection 6 MODIS products (doi: http://dx.doi. org/10.5067/MODIS/MYD06_L2.006) are publicly available from the NASA and Atmosphere Archive and Distribution System (LAADS, http:// ladsweb.nascom.nasa.gov). The CloudSat/CALIPSO 2C‐ICE (version 4; doi:10.1002/2015JD023600) products are publicly available from the CloudSat Data Processing Center (http://www.cloudsat.cira.colostate. edu/data‐products). The instM_3d_asm_Np products (3D, monthly mean instantaneous, pressure‐ level, assimilated meteorological fields, version 5.12.4) are from the Modern‐ Era Retrospective Analysis for Research and Applications, Version 2 (MERRA‐ 2; doi: 10.1175/JCLI‐D‐16‐0758.1) and are publicly available from the NASA Goddard Earth Sciences (GES) Data and Information Services Center (https://disc.gsfc.nasa.gov/).
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2019/2/16
Y1 - 2019/2/16
N2 - Spaceborne passive instruments are widely used to infer long-term ice cloud properties due to their large temporal and spatial coverage. Although observations from active instruments demonstrate ice particle variability in the vertical dimension, a pragmatic assumption made in passive cloud retrieval algorithms is that the observed scene consists of a plane-parallel cloud. In this study, a theoretical exploration on how ice cloud vertical heterogeneity (ICVH) influences passive retrievals (i.e., cloud optical thickness, cloud effective radius, and ice water path, IWP) is implemented at the pixel scale. Specifically, with an established ice cloud profile database inferred from 1-year Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation/CloudSat, we quantitatively estimate ICVH-induced biases on monthly averaged cloud macrophysical and radiative properties. Results show an average underestimation (−35%) of Moderate Resolution Imaging Spectroradiometer (MODIS) monthly IWP due to the ICVH for global ice clouds over ocean. The ICVH impacts are enhanced at large IWPs (e.g., > 500 g/m 2 ) and solar zenith angles, resulting in a profound underestimation of MODIS IWP (up to −50%) in deep convective regions and middle to high-latitude regions in the winter hemisphere. The global-averaged ice cloudy-sky reflected solar radiation and outgoing longwave radiation derived from MODIS retrievals are slightly overestimated, suggesting that the ICVH has little impact on cloud radiative properties. Relatively large reflected solar radiation (0.3 W/m 2 ) and outgoing longwave radiation (0.1 W/m 2 ) flux differences occur at high and low IWPs, respectively. The largest total flux difference (~2 W/m 2 ), mainly contributed by shortwave part, is associated with deep convection where the typical IWP is greater than 2,000 g/m 2 .
AB - Spaceborne passive instruments are widely used to infer long-term ice cloud properties due to their large temporal and spatial coverage. Although observations from active instruments demonstrate ice particle variability in the vertical dimension, a pragmatic assumption made in passive cloud retrieval algorithms is that the observed scene consists of a plane-parallel cloud. In this study, a theoretical exploration on how ice cloud vertical heterogeneity (ICVH) influences passive retrievals (i.e., cloud optical thickness, cloud effective radius, and ice water path, IWP) is implemented at the pixel scale. Specifically, with an established ice cloud profile database inferred from 1-year Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation/CloudSat, we quantitatively estimate ICVH-induced biases on monthly averaged cloud macrophysical and radiative properties. Results show an average underestimation (−35%) of Moderate Resolution Imaging Spectroradiometer (MODIS) monthly IWP due to the ICVH for global ice clouds over ocean. The ICVH impacts are enhanced at large IWPs (e.g., > 500 g/m 2 ) and solar zenith angles, resulting in a profound underestimation of MODIS IWP (up to −50%) in deep convective regions and middle to high-latitude regions in the winter hemisphere. The global-averaged ice cloudy-sky reflected solar radiation and outgoing longwave radiation derived from MODIS retrievals are slightly overestimated, suggesting that the ICVH has little impact on cloud radiative properties. Relatively large reflected solar radiation (0.3 W/m 2 ) and outgoing longwave radiation (0.1 W/m 2 ) flux differences occur at high and low IWPs, respectively. The largest total flux difference (~2 W/m 2 ), mainly contributed by shortwave part, is associated with deep convection where the typical IWP is greater than 2,000 g/m 2 .
KW - ice cloud
KW - ice water path
KW - outgoing longwave radiation
KW - reflective shortwave radiation
KW - vertical heterogeneity
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U2 - 10.1029/2018JD029681
DO - 10.1029/2018JD029681
M3 - Article
AN - SCOPUS:85060910240
VL - 124
SP - 1578
EP - 1595
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 3
ER -