The CALIPSO version 4 automated aerosol classification and lidar ratio selection algorithm

Kim, Man‐Hae; Omar, Ali; Tackett, Jason L.; Vaughan, Mark; Winker, David M.; Trepte, Charles R.; Hu, Yongxiang; Liu, Zhaoyan; Poole, L. R.; Pitts, Mıchael; Kar, Jayanta; Magill, Brian

doi:10.5194/amt-11-6107-2018

Cited by 414 publications

(376 citation statements)

References 104 publications

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“…The V4 probability density functions reflect extensive calibration updates in level 1 data to more accurately differentiate clouds and aerosols. These updates have improved previous misclassifications of lofted dust and smoke, as well as stratospheric aerosol layers (Kim et al, ). All aerosol layers detected between the surface and 30‐km altitude are classified by type.…”

Section: Methodsologymentioning

confidence: 95%

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New Estimates of Aerosol Direct Radiative Effects and Forcing From A‐Train Satellite Observations

Matus

L’Ecuyer

Henderson

2019

Geophysical Research Letters

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Aerosol direct radiative effects are assessed using multi‐sensor observations from the A‐Train satellite constellation. By leveraging vertical cloud and aerosol information from CloudSat and CALIPSO, this study reports new global estimates of aerosol radiative effects and the component owing to anthropogenic aerosols. We estimate that the global mean aerosol direct radiative effect is −2.40 W/m2 with an error of ± 0.6 W/m2 owing to uncertainties in aerosol type classification and optical depth retrievals. Anthropogenic direct radiative forcing is assessed using new observation‐based aerosol radiative kernels. Anthropogenic aerosols are found to account for 21% of the global radiative effect, or −0.50 ± 0.3 W/m2, mainly from sulfate pollution (−0.54 W/m2) partially offset by absorption from smoke (0.03 W/m2). Uncertainty estimates effectively rule out the possibility that anthropogenic aerosols warm the planet, although strong positive forcing is observed locally where anthropogenic aerosols reside above clouds and bright surfaces.

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Section: Methodsologymentioning

confidence: 95%

“…To better understand the impacts of anthropogenic aerosols, we quantify the contributions to DRE of individual aerosol types. This study will present results for several aerosol types, as identified using the CALIPSO version 4.1 (V4) aerosol classification (Kim et al, 2018).…”

Section: Methodsologymentioning

confidence: 99%

New Estimates of Aerosol Direct Radiative Effects and Forcing From A‐Train Satellite Observations

Matus

L’Ecuyer

Henderson

2019

Geophysical Research Letters

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“…Data with PDR values in between the thresholds of dust and nondust are considered as a mixture, and a fraction of dust in such mixture is derived from the definition of PDR (Yu et al, , Yu, Chin, Bian, et al, ). Dust extinction is then calculated by multiplying the so‐obtained dust backscatter coefficient by the characteristic dust lidar ratio of 44 sr, consistent with the number used in the CALIOP V4 product (Kim et al, ). Finally, CALIOP DOD is calculated by integrating the dust extinction profile in the vertical.…”

Section: Data and Approachesmentioning

confidence: 99%

Estimates of African Dust Deposition Along the Trans‐Atlantic Transit Using the Decadelong Record of Aerosol Measurements from CALIOP, MODIS, MISR, and IASI

et al. 2019

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Deposition of mineral dust into ocean fertilizes ecosystems and influences biogeochemical cycles and climate. In situ observations of dust deposition are scarce, and model simulations depend on the highly parameterized representations of dust processes with few constraints. By taking advantage of satellites' routine sampling on global and decadal scales, we estimate African dust deposition flux and loss frequency (a ratio of deposition flux to mass loading) along the trans‐Atlantic transit using the three‐dimensional distributions of aerosol retrieved by spaceborne lidar (Cloud‐Aerosol Lidar with Orthogonal Polarization [CALIOP]) and radiometers (Moderate Resolution Imaging Spectroradiometer [MODIS], Multiangle Imaging Spectroradiometer [MISR], and Infrared Atmospheric Sounding Interferometer [IASI]). On the basis of a 10‐year (2007‐2016) and basin‐scale average, the amount of dust deposition into the tropical Atlantic Ocean is estimated at 136‐222 Tg/year. The 65‐83% of satellite‐based estimates agree with the in situ climatology within a factor of 2. The magnitudes of dust deposition are highest in boreal summer and lowest in fall, whereas the interannual variability as measured by the normalized standard deviation with mean is largest in spring (28‐41%) and smallest (7‐15%) in summer. The dust deposition displays high spatial heterogeneity, revealing that the meridional shifts of major dust deposition belts are modulated by the seasonal migration of the intertropical convergence zone. On the basis of the annual and basin mean, the dust loss frequency derived from the satellite observations ranges from 0.078 to 0.100 day‐1, which is lower than model simulations by up to factors of 2 to 5. The most efficient loss of dust occurs in winter, consistent with the higher possibility of low‐altitude transported dust in southern trajectories being intercepted by rainfall associated with the intertropical convergence zone. The satellite‐based estimates of dust deposition can be used to fill the geographical gaps and extend time span of in situ measurements, study the dust‐ocean interactions, and evaluate model simulations of dust processes.

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“…Two data sets were used in this study employing the preceding instruments. The merged CloudSat CALIPSO 2B CLDCLASS LiDAR R04 product (hereafter combined CloudSat/CALIPSO) combined with the European Centre for Medium‐range Weather Forecasts Auxiliary (ECMWF‐AUX) product (Partain, ; Sassen et al, ; Wang et al, ) and the merged aerosol and cloud CALIPSO 5 km (level 2, v4.1) layer product (Kim et al, ; Winker, ).…”

Section: Methodsmentioning

confidence: 99%

“…We should mention here that data from CALIPSO version 3 have been used to retrieve the combined CloudSat/CALIPSO data set (R04). This older version of CALIPSO algorithms have been improved since and evaluated, to some extent, against the newer one (v4.1; Kar et al, ; Kim et al, ). A notable difference from v3 is that all aerosol subtypes are allowed over polar region and the aerosol classification algorithm no longer uses snow, ice, and tundra as decision points.…”

Section: Methodsmentioning

confidence: 99%

Aerosol Effect on the Cloud Phase of Low‐Level Clouds Over the Arctic

et al. 2019

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Three years of nighttime Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation data was used in synergy with CloudSat measurements to quantify how strongly aerosol type and aerosol load affect the cloud phase in low‐level clouds over the Arctic. Supercooled liquid layers were present in the majority of observed low‐level clouds (0.75 ≤ z ≤ 3.5 km) between −10 and −25 °C. Furthermore, based on the subset (6%) of data with high quality assurance for aerosol typing, ice formation is more common in the presence of dust or continental aerosols as opposed to marine or elevated smoke aerosols. With the first aerosol group, glaciated clouds were found at cloud top temperatures of 2 to 4 °C warmer than with the latter aerosol types. Further association of the aerosol concentration with the cloud phase showed that the aerosol concentration outweighs the aerosol type effect. Depending on the aerosol load, the temperature at which a cloud completely glaciates can vary by up to 6–10 °C. However, this behavior was most pronounced in stable atmospheric conditions and absent over open ocean with lower tropospheric stability values and probably less stratified clouds. Finally, more mixed‐phase clouds were associated with high aerosol load, suggesting that mixed‐phase clouds have an extended lifetime in the Arctic under high cloud condensation nuclei concentrations. This implies that in a pristine environment, with few or no local aerosol sources, and under the investigated conditions the amount of aerosol particles affects the cloud phase more than the aerosol type does.

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The CALIPSO version 4 automated aerosol classification and lidar ratio selection algorithm

Cited by 414 publications

References 104 publications

New Estimates of Aerosol Direct Radiative Effects and Forcing From A‐Train Satellite Observations

New Estimates of Aerosol Direct Radiative Effects and Forcing From A‐Train Satellite Observations

Estimates of African Dust Deposition Along the Trans‐Atlantic Transit Using the Decadelong Record of Aerosol Measurements from CALIOP, MODIS, MISR, and IASI

Aerosol Effect on the Cloud Phase of Low‐Level Clouds Over the Arctic

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