TY - JOUR
T1 - Assessment and Error Analysis of Terra-MODIS and MISR Cloud-Top Heights Through Comparison With ISS-CATS Lidar
AU - Mitra, Arka
AU - Di Girolamo, Larry
AU - Hong, Yulan
AU - Zhan, Yizhe
AU - Mueller, Kevin J.
N1 - Funding Information:
This research was supported under MISR project contract 147871 with the Jet Propulsion Laboratory, California Institute of Technology. Partial support from the NASA ACCESS program under contract NNX16AMO7A is also acknowledged. We are thankful to the NASA MODIS, MISR, and CATS teams for supplying the documentation and tools, especially the MISR toolkit ( https://nasa.github.io/MISR-Toolkit/html/index.html ). Data were stored, and computation was conducted on the University of Illinois, Urbana‐Champaign School of Earth, Society, and Environment (SESE) computer cluster, Keeling. We are thankful to Catherine Moroney for providing the data used to calculate MISR stereo errors for near‐surface retrievals. We also thank Puja Roy and Jesse Loveridge for the many fruitful discussions and inputs.
Funding Information:
This research was supported under MISR project contract 147871 with the Jet Propulsion Laboratory, California Institute of Technology. Partial support from the NASA ACCESS program under contract NNX16AMO7A is also acknowledged. We are thankful to the NASA MODIS, MISR, and CATS teams for supplying the documentation and tools, especially the MISR toolkit (https://nasa.github.io/MISR-Toolkit/html/index.html). Data were stored, and computation was conducted on the University of Illinois, Urbana-Champaign School of Earth, Society, and Environment (SESE) computer cluster, Keeling. We are thankful to Catherine Moroney for providing the data used to calculate MISR stereo errors for near-surface retrievals. We also thank Puja Roy and Jesse Loveridge for the many fruitful discussions and inputs.
Publisher Copyright:
© 2021. The Authors.
PY - 2021/5/8
Y1 - 2021/5/8
N2 - Cloud-top heights (CTH) from the Multiangle Imaging Spectroradiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra constitute our longest-running single-platform CTH record from a stable orbit. Here, we provide the first evaluation of the Terra Level 2 CTH record against collocated International Space Station Cloud-Aerosol Transport System (CATS) lidar observations between 50ºN and 50ºS. Bias and precision of Terra CTH relative to CATS is shown to be strongly tied to cloud horizontal and vertical heterogeneity and altitude. For single-layered, unbroken, optically thick clouds observed over all altitudes, the uncertainties in MODIS and MISR CTH are −540 ± 690 m and −280 ± 370 m, respectively. The uncertainties are generally smaller for lower altitude clouds and larger for optically thin clouds. For multi-layered clouds, errors are summarized herein using both absolute CTH and CATS-layer-altitude proximity to Terra CTH. We show that MISR detects the lower cloud in a two-layered system, provided top-layer optical depth <∼0.3, but MISR low-cloud CTH errors are unaltered by the presence of thin cirrus. Systematic and random errors are propagated to explain inter-sensor disagreements, as well as to provide the first estimate of the MISR stereo-opacity bias. For MISR, altitude-dependent wind-retrieval bias (−90 to −110 m) and stereo-opacity bias (−60 to −260 m) and for MODIS, CO2-slicing bias due to geometrically thick cirrus leads to overall negative CTH bias. MISR’s precision is largely driven by precision in retrieved wind-speed (3.7 m s−1), whereas MODIS precision is driven by forward-modeling uncertainty.
AB - Cloud-top heights (CTH) from the Multiangle Imaging Spectroradiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra constitute our longest-running single-platform CTH record from a stable orbit. Here, we provide the first evaluation of the Terra Level 2 CTH record against collocated International Space Station Cloud-Aerosol Transport System (CATS) lidar observations between 50ºN and 50ºS. Bias and precision of Terra CTH relative to CATS is shown to be strongly tied to cloud horizontal and vertical heterogeneity and altitude. For single-layered, unbroken, optically thick clouds observed over all altitudes, the uncertainties in MODIS and MISR CTH are −540 ± 690 m and −280 ± 370 m, respectively. The uncertainties are generally smaller for lower altitude clouds and larger for optically thin clouds. For multi-layered clouds, errors are summarized herein using both absolute CTH and CATS-layer-altitude proximity to Terra CTH. We show that MISR detects the lower cloud in a two-layered system, provided top-layer optical depth <∼0.3, but MISR low-cloud CTH errors are unaltered by the presence of thin cirrus. Systematic and random errors are propagated to explain inter-sensor disagreements, as well as to provide the first estimate of the MISR stereo-opacity bias. For MISR, altitude-dependent wind-retrieval bias (−90 to −110 m) and stereo-opacity bias (−60 to −260 m) and for MODIS, CO2-slicing bias due to geometrically thick cirrus leads to overall negative CTH bias. MISR’s precision is largely driven by precision in retrieved wind-speed (3.7 m s−1), whereas MODIS precision is driven by forward-modeling uncertainty.
KW - MISR
KW - Terra MODIS
KW - Terra satellite
KW - cloud-top heights
KW - error analysis
KW - stereo-opacity bias
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U2 - 10.1029/2020JD034281
DO - 10.1029/2020JD034281
M3 - Article
C2 - 34221784
AN - SCOPUS:85105570804
SN - 2169-897X
VL - 126
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
IS - 9
M1 - e2020JD034281
ER -