The Cloudsat Mission and the a-Train

Stephens, Graeme L.; Vane, D.; Boain, R. J.; Mace, Gerald G.; Sassen, Kenneth; Wang, Zhien; Illingworth, Anthony J.; O’Connor, Ewan; Rossow, William B.; Durden, Stephen L.; Miller, Steven D.; Austin, R. T.; Benedetti, Angela; Mitrescu, C.

doi:10.1175/bams-83-12-1771

Cited by 1,919 publications

(1,021 citation statements)

References 49 publications

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“…In December 2009, PARASOL was maneuvered out of the Afternoon Constellation, known as the "A-Train" (Nakajima et al, 2010b;Stephens et al, 2002). The POLDER measurements before 2009 agree well with those of other sensors (Stubenrauch et al, 2013;Zeng et al, 2011).…”

Section: Polder Multi-angle Polarized Observationsmentioning

confidence: 58%

Impact of cloud horizontal inhomogeneity and directional sampling on the retrieval of cloud droplet size by the POLDER instrument

et al. 2015

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Abstract. The principles of cloud droplet size retrieval via Polarization and Directionality of the Earth's Reflectance (POLDER) requires that clouds be horizontally homogeneous. The retrieval is performed by combining all measurements from an area of 150 km × 150 km to compensate for POLDER's insufficient directional sampling. Using POLDER-like data simulated with the RT3 model, we investigate the impact of cloud horizontal inhomogeneity and directional sampling on the retrieval and analyze which spatial resolution is potentially accessible from the measurements. Case studies show that the sub-grid-scale variability in droplet effective radius (CDR) can significantly reduce valid retrievals and introduce small biases to the CDR (∼ 1.5 µm) and effective variance (EV) estimates. Nevertheless, the sub-grid-scale variations in EV and cloud optical thickness (COT) only influence the EV retrievals and not the CDR estimate. In the directional sampling cases studied, the retrieval using limited observations is accurate and is largely free of random noise.Several improvements have been made to the original POLDER droplet size retrieval. For example, measurements in the primary rainbow region (137-145 • ) are used to ensure retrievals of large droplet (> 15 µm) and to reduce the uncertainties caused by cloud heterogeneity. We apply the improved method using the POLDER global L1B data from June 2008, and the new CDR results are compared with the operational CDRs. The comparison shows that the operational CDRs tend to be underestimated for large droplets because the cloudbow oscillations in the scattering angle region of 145-165 • are weak for cloud fields with CDR > 15 µm. Finally, a sub-grid-scale retrieval case demonstrates that a higher resolution, e.g., 42 km × 42 km, can be used when inverting cloud droplet size distribution parameters from POLDER measurements.

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Section: Polder Multi-angle Polarized Observationsmentioning

confidence: 58%

Impact of cloud horizontal inhomogeneity and directional sampling on the retrieval of cloud droplet size by the POLDER instrument

et al. 2015

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“…The cloud profiling radar (CPR) of the CloudSat mission (Stephens et al, 2002;Mace et al, 2007) is capable of probing optically thick cloud layers and therefore provides the correct cloud base. Combined with the information on optically thin cloud layers from CALIOP, these two instruments provide a complete vertical profiling of all clouds.…”

Section: Airs Calipso and L2 Radar-lidar Geoprof Data And Their Collmentioning

confidence: 99%

“…The TIROS-N Operational Vertical Sounders onboard the NOAA polar satellites provide data since 1979, the Atmospheric InfraRed Sounder (AIRS) onboard Aqua since 2002 and the IR Atmospheric Sounding Interferometer (IASI) onboard METOP since 2006. The ATrain mission (Stephens et al, 2002), consisting of several passive and two active remote sensing instruments in constellation with the Aqua satellite, provides a unique possibility to explore the geometrical depth and multi-layer structure of clouds. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission (Winker et al, 2007) is also sensitive to very thin cirrus (such as subvisible cirrus with optical depth down to 0.01) and provides information on multiple cloud layers as long as clouds are optically not too thick.…”

Section: Introductionmentioning

confidence: 99%

“…The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission (Winker et al, 2007) is also sensitive to very thin cirrus (such as subvisible cirrus with optical depth down to 0.01) and provides information on multiple cloud layers as long as clouds are optically not too thick. In the latter case, the cloud profiling radar (CPR) of the CloudSat mission (Stephens et al, 2002;Mace et al, 2007) helps to complete the information on vertical cloud layer structure. For this purpose, the Cloudsat Geometrical Profiling Product (GEOPROF; Mace et al, 2007;Marchand et al, 2008) and the CALIPSO Vertical Feature Mask (VFM, Vaughan et al, 2004) have been merged into a combined Radar-Lidar Geometrical Profile Product (Radar -Lidar GEOPROF; Mace et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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A 6-year global cloud climatology from the Atmospheric InfraRed Sounder AIRS and a statistical analysis in synergy with CALIPSO and CloudSat

et al. 2010

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Abstract. We present a six-year global climatology of cloud properties, obtained from observations of the Atmospheric Infrared Sounder (AIRS) onboard the NASA Aqua satellite. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) combined with CloudSat observations, both missions launched as part of the A-Train in 2006, provide a unique opportunity to evaluate the retrieved AIRS cloud properties such as cloud amount and height. In addition, they permit to explore the vertical structure of different cloud types. AIRS-LMD cloud detection agrees with CALIPSO about 85% over ocean and about 75% over land. Global cloud amount has been estimated from 66% to 74%, depending on the weighting of not cloudy AIRS footprints by partial cloud cover from 0 to 0.3. 42% of all clouds are high clouds, and about 42% of all clouds are single layer low-level clouds. The "radiative" cloud height determined by the AIRS-LMD retrieval corresponds well to the height of the maximum backscatter signal and of the "apparent middle" of the cloud. Whereas the real cloud thickness of high opaque clouds often fills the whole troposphere, their "apparent" cloud thickness (at which optical depth reaches about 5) is on average only 2.5 km. The real geometrical thickness of optically thin cirrus as identified by AIRS-LMD is identical to the "apparent" cloud thickness with an average of about 2.5 km in the tropics and midlatitudes. High clouds in the tropics have slightly more diffusive cloud tops than at higher latitudes. In general, the depth of the maximum backscatter signal increases nearly linearly with increasing "apparent" cloud thickness. For the same "apparent" cloud thicknessCorrespondence to: C. J. Stubenrauch (stubenrauch@lmd.polytechnique.fr) optically thin cirrus show a maximum backscatter about 10% deeper inside the cloud than optically thicker clouds. We also show that only the geometrically thickest opaque clouds and (the probably surrounding anvil) cirrus penetrate the stratosphere in the tropics.

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“…The primary CloudSat instrument is a 94 GHz nadir-pointing cloud profiling radar, which measures radar backscatter from clouds as a function of distance from the instrument [Stephens et al, 2002]. Where possible, we use Level 2 (along-track) Cloud Water Content-Radar Only (2B-CWC-RO) profiles of cloud water content (CWC) to determine the HDL of MCSs observed by ISCCP.…”

Section: Datamentioning

confidence: 99%

Relationships between convective structure and transport of aerosols to the upper troposphere deduced from satellite observations

Chakraborty

Wright

et al. 2015

JGR Atmospheres

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We estimate the extent of upper tropospheric aerosol layers (UT ALs) surrounding mesoscale convective systems (MCSs) and explore the relationships between UT AL extent and the morphology, location, and developmental stage of collocated MCSs in the tropics. Our analysis is based on satellite data collected over equatorial Africa, South Asia, and the Amazon basin between June 2006 and June 2008. We identify substantial variations in the relationships between convective properties and aerosol transport by region and stage of convective development. The most extensive UT ALs over equatorial Africa are associated with mature MCSs, while the most extensive UT ALs over South Asia and the Amazon are associated with growing MCSs. Convective aerosol transport over the Amazon is weaker than that observed over the other two regions despite similar transport frequencies, likely due to the smaller sizes and shorter mean lifetimes of MCSs over the Amazon. Variations in UT ALs in the vicinity of tropical MCSs are primarily explained by variations in the horizontal sizes of the associated MCSs and are largely unrelated to aerosol loading in the lower troposphere. We also identify potentially important relationships with the number of convective cores, vertical wind shear, and convective fraction during the growing and mature stages of MCS development. Relationships between convective properties and aerosol transport are relatively weak during the decaying stage of convective development. Our results provide an interpretive framework for devising and evaluating numerical model experiments that examine relationships between convective properties and ALs in the upper troposphere.

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The Cloudsat Mission and the a-Train

Cited by 1,919 publications

References 49 publications

Impact of cloud horizontal inhomogeneity and directional sampling on the retrieval of cloud droplet size by the POLDER instrument

Impact of cloud horizontal inhomogeneity and directional sampling on the retrieval of cloud droplet size by the POLDER instrument

A 6-year global cloud climatology from the Atmospheric InfraRed Sounder AIRS and a statistical analysis in synergy with CALIPSO and CloudSat

Relationships between convective structure and transport of aerosols to the upper troposphere deduced from satellite observations

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