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A Multi-Year Study of GOES-13 Droplet Effective Radius Retrievals for Warm Clouds over South America and Southeast Pacific. ATMOSPHERE 2022. [DOI: 10.3390/atmos13010077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Geostationary satellites can retrieve the cloud droplet effective radius (re) but suffer biases from cloud inhomogeneities, internal retrieval nonlinearities, and 3-D scattering/shadowing from neighboring clouds, among others. A 1-D retrieval method was applied to Geostationary Operational Environmental Satellite 13 (GOES-13) imagery, over large areas in South America (5∘ N–30∘ S; 20∘–70∘ W), the Southeast Pacific (5∘ N–30∘ S; 70∘–120∘ W), and the Amazon (2∘ N–7∘ S; 54∘–73∘ W), for four months in each year from 2014–2017. Results were compared against in situ aircraft measurements and the Moderate Resolution Imaging Spectroradiometer cloud product for Terra and Aqua satellites. Monthly regression parameters approximately followed a seasonal pattern. With up to 108,009 of matchups, slope, intercept, and correlation for Terra (Aqua) ranged from about 0.71 to 1.17, −2.8 to 2.5 μm, and 0.61 to 0.91 (0.54 to 0.78, −1.5 to 1.8 μm, 0.63 to 0.89), respectively. We identified evidence for re overestimation (underestimation) correlated with shadowing (enhanced reflectance) in the forward (backscattering) hemisphere, and limitations to illumination and viewing configurations accessible by GOES-13, depending on the time of day and season. A proposition is hypothesized to ameliorate 3-D biases by studying relative illumination and cloud spatial inhomogeneity.
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2
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Zang L, Rosenfeld D, Mao F, Pan Z, Zhu Y, Gong W, Wang Z. CALIOP retrieval of droplet effective radius accounting for cloud vertical homogeneity. OPTICS EXPRESS 2021; 29:21921-21935. [PMID: 34265968 DOI: 10.1364/oe.427022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/03/2021] [Indexed: 06/13/2023]
Abstract
Monitoring cloud droplet effective radius (re) is of great significance for studying aerosol-cloud interactions (ACI). Passive satellite retrieval, e.g., MODIS (Moderate Resolution Imaging Spectroradiometer), requires sunlight. This requirement prompted developing re retrieval using active sensors, e.g., CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization). Given the highest sensitivity of vertically homogeneous clouds to aerosols that feed to cloud base, here CALIOP profile measurements were used for the first time to quantify cloud vertical homogeneity and estimate cloud re during both day and night. Comparison using simultaneous Aqua-MODIS measurements demonstrates that CALIOP retrieval has the highest accuracy for vertically homogeneous clouds, with R2 (MAE, RMSE) of 0.72 (1.75 µm, 2.25 µm), while the accuracy is lowest for non-homogeneous clouds, with R2 (MAE, RMSE) of 0.60 (2.90 µm, 3.70 µm). The improved re retrieval in vertically homogeneous clouds provides a basis for possible breakthrough insights in ACI by CALIOP since re in such clouds reflects most directly aerosol effects on cloud properties. Global day-night maps of cloud vertical homogeneity and respective re are presented.
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3
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Derivation of Shortwave Radiometric Adjustments for SNPP and NOAA-20 VIIRS for the NASA MODIS-VIIRS Continuity Cloud Products. REMOTE SENSING 2020. [DOI: 10.3390/rs12244096] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Climate studies, including trend detection and other time series analyses, necessarily require stable, well-characterized and long-term data records. For satellite-based geophysical retrieval datasets, such data records often involve merging the observational records of multiple similar, though not identical, instruments. The National Aeronautics and Space Administration (NASA) cloud mask (CLDMSK) and cloud-top and optical properties (CLDPROP) products are designed to bridge the observational records of the Moderate-resolution Imaging Spectroradiometer (MODIS) onboard NASA’s Aqua satellite and the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the joint NASA/National Oceanic and Atmospheric Administration (NOAA) Suomi National Polar-orbiting Partnership (SNPP) satellite and NOAA’s new generation of operational polar-orbiting weather platforms (NOAA-20+). Early implementations of the CLDPROP algorithms on Aqua MODIS and SNPP VIIRS suffered from large intersensor biases in cloud optical properties that were traced back to relative radiometric inconsistency in analogous shortwave channels on both imagers, with VIIRS generally observing brighter top-of-atmosphere spectral reflectance than MODIS (e.g., up to 5% brighter in the 0.67 µm channel). Radiometric adjustment factors for the SNPP and NOAA-20 VIIRS shortwave channels used in the cloud optical property retrievals are derived from an extensive analysis of the overlapping observational records with Aqua MODIS, specifically for homogenous maritime liquid water cloud scenes for which the viewing/solar geometry of MODIS and VIIRS match. Application of these adjustment factors to the VIIRS L1B prior to ingestion into the CLDMSK and CLDPROP algorithms yields improved intersensor agreement, particularly for cloud optical properties.
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Multi-View Polarimetric Scattering Cloud Tomography and Retrieval of Droplet Size. REMOTE SENSING 2020. [DOI: 10.3390/rs12172831] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Tomography aims to recover a three-dimensional (3D) density map of a medium or an object. In medical imaging, it is extensively used for diagnostics via X-ray computed tomography (CT). We define and derive a tomography of cloud droplet distributions via passive remote sensing. We use multi-view polarimetric images to fit a 3D polarized radiative transfer (RT) forward model. Our motivation is 3D volumetric probing of vertically-developed convectively-driven clouds that are ill-served by current methods in operational passive remote sensing. Current techniques are based on strictly 1D RT modeling and applied to a single cloudy pixel, where cloud geometry defaults to that of a plane-parallel slab. Incident unpolarized sunlight, once scattered by cloud-droplets, changes its polarization state according to droplet size. Therefore, polarimetric measurements in the rainbow and glory angular regions can be used to infer the droplet size distribution. This work defines and derives a framework for a full 3D tomography of cloud droplets for both their mass concentration in space and their distribution across a range of sizes. This 3D retrieval of key microphysical properties is made tractable by our novel approach that involves a restructuring and differentiation of an open-source polarized 3D RT code to accommodate a special two-step optimization technique. Physically-realistic synthetic clouds are used to demonstrate the methodology with rigorous uncertainty quantification.
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Fu D, Di Girolamo L, Liang L, Zhao G. Regional Biases in MODIS Marine Liquid Water Cloud Drop Effective Radius Deduced Through Fusion With MISR. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:13182-13196. [PMID: 32025454 PMCID: PMC6988446 DOI: 10.1029/2019jd031063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 06/10/2023]
Abstract
Satellite measurements from Terra's Moderate Resolution Imaging Spectroradiometer (MODIS) represent our longest, single-platform, global record of the effective radius (Re) of the cloud drop size distribution. Quantifying its error characteristics has been challenging because systematic errors in retrieved Re covary with the structural characteristics of the cloud and the Sun-view geometry. Recently, it has been shown that the bias in MODIS Re can be estimated by fusing MODIS data with data from Terra's Multi-angle Imaging SpectroRadiometer (MISR). Here, we relate the bias to the observed underlying conditions to derive regional-scale, bias-corrected, monthly-mean Re 1.6 , Re 2.1 , and Re 3.7 values retrieved from the 1.6, 2.1, and 3.7 μm MODIS spectral channels. Our results reveal that monthly-mean bias in Re 2.1 exhibits large regional dependency, ranging from at least ~1 to 10 μm (15 to 60%) varying with scene heterogeneity, optical depth, and solar zenith angle. Regional bias-corrected monthly-mean Re 2.1 ranges from 4 to 17 μm, compared to 10 to 25 μm for uncorrected Re 2.1 , with estimated uncertainties of 0.1 to 1.8 μm. The bias-corrected monthly-mean Re 3.7 and Re 2.1 show difference of approximately +0.6 μm in the coastal marine stratocumulus regions and down to approximately -2 μm in the cumuliform cloud regions, compared to uncorrected values of about -1 to -6 μm, respectively. Bias-corrected Re values compare favorably to other independent data sources, including field observations, global model simulations, and satellite retrievals that do not use retrieval techniques similar to MODIS. This work changes the interpretation of global Re distributions from MODIS Re products and may further impact studies, which use the original MODIS Re products to study, for example, aerosol-cloud interactions and cloud microphysical parameterization.
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Affiliation(s)
- Dongwei Fu
- Department of Atmospheric SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Larry Di Girolamo
- Department of Atmospheric SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | | | - Guangyu Zhao
- Department of Atmospheric SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
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6
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Retrieval of Cloud Optical Thickness from Sky-View Camera Images using a Deep Convolutional Neural Network based on Three-Dimensional Radiative Transfer. REMOTE SENSING 2019. [DOI: 10.3390/rs11171962] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Observation of the spatial distribution of cloud optical thickness (COT) is useful for the prediction and diagnosis of photovoltaic power generation. However, there is not a one-to-one relationship between transmitted radiance and COT (so-called COT ambiguity), and it is difficult to estimate COT because of three-dimensional (3D) radiative transfer effects. We propose a method to train a convolutional neural network (CNN) based on a 3D radiative transfer model, which enables the quick estimation of the slant-column COT (SCOT) distribution from the image of a ground-mounted radiometrically calibrated digital camera. The CNN retrieves the SCOT spatial distribution using spectral features and spatial contexts. An evaluation of the method using synthetic data shows a high accuracy with a mean absolute percentage error of 18% in the SCOT range of 1–100, greatly reducing the influence of the 3D radiative effect. As an initial analysis result, COT is estimated from a sky image taken by a digital camera, and a high correlation is shown with the effective COT estimated using a pyranometer. The discrepancy between the two is reasonable, considering the difference in the size of the field of view, the space–time averaging method, and the 3D radiative effect.
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7
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Abstract
Linearizations of the spherical harmonic discrete ordinate method (SHDOM) by means of a forward and a forward-adjoint approach are presented. Essentially, SHDOM is specialized for derivative calculations and radiative transfer problems involving the delta-M approximation, the TMS correction, and the adaptive grid splitting, while practical formulas for computing the derivatives in the spherical harmonics space are derived. The accuracies and efficiencies of the proposed methods are analyzed for several test problems.
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8
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Three-Dimensional Cloud Volume Reconstruction from the Multi-angle Imaging SpectroRadiometer. REMOTE SENSING 2018. [DOI: 10.3390/rs10111858] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Characterizing 3-D structure of clouds is needed for a more complete understanding of the Earth’s radiative and latent heat fluxes. Here we develop and explore a ray casting algorithm applied to data from the Multi-angle Imaging SpectroRadiometer (MISR) onboard the Terra satellite, in order to reconstruct 3-D cloud volumes of observed clouds. The ray casting algorithm is first applied to geometrically simple synthetic clouds to show that, under the assumption of perfect, clear-conservative cloud masks, the reconstruction method yields overestimation in the volume whose magnitude depends on the cloud geometry and the resolution of the reconstruction grid relative to the image pixel resolution. The method is then applied to two hand-picked MISR scenes, fully accounting for MISR’s viewing geometry for reconstructions over the Earth’s ellipsoidal surface. The MISR Radiometric Camera-by-camera Cloud Mask (RCCM) at 1.1-km resolution and the custom cloud mask at 275-m resolution independently derived from MISR’s red, green, and blue channels are used as input cloud masks. A wind correction method, termed cloud spreading, is applied to the cloud masks to offset potential cloud movements over short time intervals between the camera views of a scene. The MISR cloud-top height product is used as a constraint to reduce the overestimation at the cloud top. The results for the two selected scenes show that the wind correction using the cloud spreading method increases the reconstructed volume up to 4.7 times greater than without the wind correction, and that the reconstructed volume generated from the RCCM is up to 3.5 times greater than that from the higher-resolution custom cloud mask. Recommendations for improving the presented cloud volume reconstructions, as well as possible future passive remote sensing satellite missions, are discussed.
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Simulation of Bidirectional Reflectance in Broken Clouds: From Individual Realization to Averaging over an Ensemble of Cloud Fields. REMOTE SENSING 2018. [DOI: 10.3390/rs10091342] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this paper, we describe the results of simulating the bidirectional reflectance in three-dimensional (3D) cloud fields. For the calculations of reflectance, we use original statistical algorithms that ensure the effects of atmospheric sphericity and molecular absorption in the solar spectral range are accounted for. Cloud fields are simulated on the basis of a Poisson model of broken clouds; clouds are approximated by truncated paraboloids of rotation. The cloud heterogeneity effect on the averaging of reflection functions over an ensemble of cloud fields is estimated using numerical averaging of the stochastic radiative transfer equation, using a randomization. The simulation is performed for a mono-directional receiver with wavelength channels 0.55 and 2.15 µm, different realizations with small and moderate cloud fractions, and a set of sun-view geometries. With the appearance of an isolated cloud in the sky, the reflection function is determined by cloud presence/absence on the line of sight (LS), shading of LS by clouds/non-obscuration directed “toward the Sun,” and illumination of LS by cloud-reflected radiation. Passage to cloud fields gives rise to such additional factors as mutual shading and multiple scattering between clouds, which are mainly determined by cloud elements located near LS and directed “toward the Sun”. Strong fluctuations of reflectance as a function of the relative azimuth angle between sun and view directions in a specific realization are smoothed out after averaging over an ensemble of cloud fields. In interpreting the results of retrieving the cloud characteristics according to measurements of reflected radiation, it should be kept in mind that for fixed illumination conditions, the mean bidirectional reflectance may differ several-fold from bidirectional reflectance in a specific 3D cloud structure.
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10
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Grosvenor DP, Sourdeval O, Zuidema P, Ackerman A, Alexandrov MD, Bennartz R, Boers R, Cairns B, Chiu JC, Christensen M, Deneke H, Diamond M, Feingold G, Fridlind A, Hünerbein A, Knist C, Kollias P, Marshak A, McCoy D, Merk D, Painemal D, Rausch J, Rosenfeld D, Russchenberg H, Seifert P, Sinclair K, Stier P, van Diedenhoven B, Wendisch M, Werner F, Wood R, Zhang Z, Quaas J. Remote Sensing of Droplet Number Concentration in Warm Clouds: A Review of the Current State of Knowledge and Perspectives. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2018; 56:409-453. [PMID: 30148283 PMCID: PMC6099364 DOI: 10.1029/2017rg000593] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 05/13/2023]
Abstract
The cloud droplet number concentration (N d) is of central interest to improve the understanding of cloud physics and for quantifying the effective radiative forcing by aerosol-cloud interactions. Current standard satellite retrievals do not operationally provide N d, but it can be inferred from retrievals of cloud optical depth (τ c) cloud droplet effective radius (r e) and cloud top temperature. This review summarizes issues with this approach and quantifies uncertainties. A total relative uncertainty of 78% is inferred for pixel-level retrievals for relatively homogeneous, optically thick and unobscured stratiform clouds with favorable viewing geometry. The uncertainty is even greater if these conditions are not met. For averages over 1° ×1° regions the uncertainty is reduced to 54% assuming random errors for instrument uncertainties. In contrast, the few evaluation studies against reference in situ observations suggest much better accuracy with little variability in the bias. More such studies are required for a better error characterization. N d uncertainty is dominated by errors in r e, and therefore, improvements in r e retrievals would greatly improve the quality of the N d retrievals. Recommendations are made for how this might be achieved. Some existing N d data sets are compared and discussed, and best practices for the use of N d data from current passive instruments (e.g., filtering criteria) are recommended. Emerging alternative N d estimates are also considered. First, new ideas to use additional information from existing and upcoming spaceborne instruments are discussed, and second, approaches using high-quality ground-based observations are examined.
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Affiliation(s)
| | - Odran Sourdeval
- Leipzig Institute for MeteorologyUniversität LeipzigLeipzigGermany
| | - Paquita Zuidema
- Department of Atmospheric SciencesRosenstiel School of Marine and Atmospheric ScienceMiamiFLUSA
| | | | - Mikhail D. Alexandrov
- NASA Goddard Institute for Space StudiesNew YorkNYUSA
- Department of Applied Physics and Applied MathematicsColumbia UniversityNew YorkNYUSA
| | - Ralf Bennartz
- Department of Earth and Environmental SciencesVanderbilt UniversityNashvilleTNUSA
- Space Science and Engineering CenterUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Reinout Boers
- Royal Netherlands Meteorological InstituteDe BiltThe Netherlands
| | - Brian Cairns
- NASA Goddard Institute for Space StudiesNew YorkNYUSA
| | - J. Christine Chiu
- Department of Atmospheric ScienceColorado State UniversityFort CollinsCOUSA
| | - Matthew Christensen
- Rutherford Appleton LaboratoryHarwellUK
- Department of PhysicsUniversity of OxfordOxfordUK
| | - Hartwig Deneke
- Leibniz Institute for Tropospheric ResearchLeipzigGermany
| | - Michael Diamond
- Department of Atmospheric SciencesUniversity of WashingtonSeattleWAUSA
| | - Graham Feingold
- Chemical Sciences Division, Earth System Research LaboratoryNational Oceanic and Atmospheric AdministrationBoulderCOUSA
| | - Ann Fridlind
- NASA Goddard Institute for Space StudiesNew YorkNYUSA
| | - Anja Hünerbein
- Leibniz Institute for Tropospheric ResearchLeipzigGermany
| | | | - Pavlos Kollias
- School of Marine and Atmospheric SciencesStony Brook UniversityStony BrookNYUSA
| | | | - Daniel McCoy
- School of Earth and EnvironmentUniversity of LeedsLeedsUK
| | - Daniel Merk
- Leibniz Institute for Tropospheric ResearchLeipzigGermany
| | | | - John Rausch
- Department of Earth and Environmental SciencesVanderbilt UniversityNashvilleTNUSA
| | - Daniel Rosenfeld
- Institute of Earth SciencesThe Hebrew University of JerusalemJerusalemIsrael
| | - Herman Russchenberg
- Department of Geoscience and Remote SensingDelft University of TechnologyDelftThe Netherlands
| | - Patric Seifert
- Leibniz Institute for Tropospheric ResearchLeipzigGermany
| | - Kenneth Sinclair
- NASA Goddard Institute for Space StudiesNew YorkNYUSA
- Department of Earth and Environmental EngineeringColumbia UniversityNew YorkNYUSA
| | - Philip Stier
- Department of PhysicsUniversity of OxfordOxfordUK
| | - Bastiaan van Diedenhoven
- NASA Goddard Institute for Space StudiesNew YorkNYUSA
- Center for Climate Systems ResearchColumbia UniversityNew YorkNYUSA
| | - Manfred Wendisch
- Leipzig Institute for MeteorologyUniversität LeipzigLeipzigGermany
| | - Frank Werner
- Joint Center for Earth Systems TechnologyBaltimoreMDUSA
| | - Robert Wood
- Department of Atmospheric SciencesUniversity of WashingtonSeattleWAUSA
| | | | - Johannes Quaas
- Leipzig Institute for MeteorologyUniversität LeipzigLeipzigGermany
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11
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Zhang Z, Werner F, Cho HM, Wind G, Platnick S, Ackerman AS, Di Girolamo L, Marshak A, Meyer K. A framework based on 2-D Taylor expansion for quantifying the impacts of sub-pixel reflectance variance and covariance on cloud optical thickness and effective radius retrievals based on the bi-spectral method. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2016; 121:7007-7025. [PMID: 32908807 PMCID: PMC7477826 DOI: 10.1002/2016jd024837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The bi-spectral method retrieves cloud optical thickness (τ) and cloud droplet effective radius (r e ) simultaneously from a pair of cloud reflectance observations, one in a visible or near infrared (VIS/NIR) band and the other in a shortwave-infrared (SWIR) band. A cloudy pixel is usually assumed to be horizontally homogeneous in the retrieval. Ignoring sub-pixel variations of cloud reflectances can lead to a significant bias in the retrieved τ and r e . In the literature, the retrievals of τ and r e are often assumed to be independent and considered separately when investigating the impact of sub-pixel cloud reflectance variations on the bi-spectral method. As a result, the impact on τ is contributed only by the sub-pixel variation of VIS/NIR band reflectance and the impact on r e only by the sub-pixel variation of SWIR band reflectance. In our new framework, we use the Taylor expansion of a two-variable function to understand and quantify the impacts of sub-pixel variances of VIS/NIR and SWIR cloud reflectances and their covariance on the τ and r e retrievals. This framework takes into account the fact that the retrievals are determined by both VIS/NIR and SWIR band observations in a mutually dependent way. In comparison with previous studies, it provides a more comprehensive understanding of how sub-pixel cloud reflectance variations impact the τ and r e retrievals based on the bi-spectral method. In particular, our framework provides a mathematical explanation of how the sub-pixel variation in VIS/NIR band influences the r e retrieval and why it can sometimes outweigh the influence of variations in the SWIR band and dominate the error in r e retrievals, leading to a potential contribution of positive bias to the r e retrieval. We test our framework using synthetic cloud fields from a large-eddy simulation and real observations from MODIS. The predicted results based on our framework agree very well with the numerical simulations. Our framework can be used to estimate the retrieval uncertainty from sub-pixel reflectance variations in operational satellite cloud products and to help understand the differences in τ and r e retrievals between two instruments.
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Affiliation(s)
- Z. Zhang
- Physics Department, UMBC, Baltimore, MD, USA
- Joint Center for Earth Systems Technology, UMBC, Baltimore, MD, USA
| | - F. Werner
- Joint Center for Earth Systems Technology, UMBC, Baltimore, MD, USA
| | - H.-M. Cho
- Joint Center for Earth Systems Technology, UMBC, Baltimore, MD, USA
- Electronics and Telecommunications Research Institute, Korea
| | - G. Wind
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Science Systems and Applications, Inc., Maryland 20706, USA
| | - S. Platnick
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - A. S. Ackerman
- NASA Goddard Institute for Space Studies, New York City, NY, USA
| | - L. Di Girolamo
- Department of Atmospheric Sciences, University of Illinois, Urbana-Champaign, IL, USA
| | - A. Marshak
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Kerry Meyer
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Universities Space Research Association (USRA), Columbia, MD, USA
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12
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Miller DJ, Zhang Z, Ackerman AS, Platnick S, Baum BA. The impact of cloud vertical profile on liquid water path retrieval based on the bispectral method: A theoretical study based on large-eddy simulations of shallow marine boundary layer clouds. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2016; 121:4122-4141. [PMID: 29637042 PMCID: PMC5889945 DOI: 10.1002/2015jd024322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Passive optical retrievals of cloud liquid water path (LWP), like those implemented for Moderate Resolution Imaging Spectroradiometer (MODIS), rely on cloud vertical profile assumptions to relate optical thickness (τ) and effective radius (re ) retrievals to LWP. These techniques typically assume that shallow clouds are vertically homogeneous; however, an adiabatic cloud model is plausibly more realistic for shallow marine boundary layer cloud regimes. In this study a satellite retrieval simulator is used to perform MODIS-like satellite retrievals, which in turn are compared directly to the large-eddy simulation (LES) output. This satellite simulator creates a framework for rigorous quantification of the impact that vertical profile features have on LWP retrievals, and it accomplishes this while also avoiding sources of bias present in previous observational studies. The cloud vertical profiles from the LES are often more complex than either of the two standard assumptions, and the favored assumption was found to be sensitive to cloud regime (cumuliform/stratiform). Confirming previous studies, drizzle and cloud top entrainment of dry air are identified as physical features that bias LWP retrievals away from adiabatic and toward homogeneous assumptions. The mean bias induced by drizzle-influenced profiles was shown to be on the order of 5-10 g/m2. In contrast, the influence of cloud top entrainment was found to be smaller by about a factor of 2. A theoretical framework is developed to explain variability in LWP retrievals by introducing modifications to the adiabatic re profile. In addition to analyzing bispectral retrievals, we also compare results with the vertical profile sensitivity of passive polarimetric retrieval techniques.
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Affiliation(s)
- Daniel J Miller
- Physics Department, University of Maryland, Baltimore County, Baltimore, Maryland, USA
| | - Zhibo Zhang
- Physics Department, University of Maryland, Baltimore County, Baltimore, Maryland, USA
- Joint Center for Earth Systems Technology, Baltimore, Maryland, USA
| | | | | | - Bryan A Baum
- Space Science and Engineering Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
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13
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Cho HM, Zhang Z, Meyer K, Lebsock M, Platnick S, Ackerman AS, Di Girolamo L, C-Labonnote L, Cornet C, Riedi J, Holz RE. Frequency and causes of failed MODIS cloud property retrievals for liquid phase clouds over global oceans. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2015; 120:4132-4154. [PMID: 27656330 PMCID: PMC5012132 DOI: 10.1002/2015jd023161] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/01/2015] [Accepted: 04/04/2015] [Indexed: 05/26/2023]
Abstract
Moderate Resolution Imaging Spectroradiometer (MODIS) retrieves cloud droplet effective radius (re ) and optical thickness (τ) by projecting observed cloud reflectances onto a precomputed look-up table (LUT). When observations fall outside of the LUT, the retrieval is considered "failed" because no combination of τ and re within the LUT can explain the observed cloud reflectances. In this study, the frequency and potential causes of failed MODIS retrievals for marine liquid phase (MLP) clouds are analyzed based on 1 year of Aqua MODIS Collection 6 products and collocated CALIOP and CloudSat observations. The retrieval based on the 0.86 µm and 2.1 µm MODIS channel combination has an overall failure rate of about 16% (10% for the 0.86 µm and 3.7 µm combination). The failure rates are lower over stratocumulus regimes and higher over the broken trade wind cumulus regimes. The leading type of failure is the "re too large" failure accounting for 60%-85% of all failed retrievals. The rest is mostly due to the "re too small" or τ retrieval failures. Enhanced retrieval failure rates are found when MLP cloud pixels are partially cloudy or have high subpixel inhomogeneity, are located at special Sun-satellite viewing geometries such as sunglint, large viewing or solar zenith angles, or cloudbow and glory angles, or are subject to cloud masking, cloud overlapping, and/or cloud phase retrieval issues. The majority (more than 84%) of failed retrievals along the CALIPSO track can be attributed to at least one or more of these potential reasons. The collocated CloudSat radar reflectivity observations reveal that the remaining failed retrievals are often precipitating. It remains an open question whether the extremely large re values observed in these clouds are the consequence of true cloud microphysics or still due to artifacts not included in this study.
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Affiliation(s)
| | - Zhibo Zhang
- Joint Center of Earth Systems Technology Baltimore Maryland USA; Physics Department University of Maryland, Baltimore County Baltimore Maryland USA
| | - Kerry Meyer
- NASA Goddard Space Flight Center Greenbelt Maryland USA; Goddard Earth Science Technology and Research Universities Space Research Association Columbia Maryland USA
| | | | | | | | - Larry Di Girolamo
- Department of Atmospheric Sciences University of Illinois at Urbana-Champaign Urbana Illinois USA
| | - Laurent C-Labonnote
- Laboratoire d'Optique Atmosphérique-Université des Sciences et Technologies de Lille/CNRS Villeneuve d'A scq France
| | - Céline Cornet
- Laboratoire d'Optique Atmosphérique-Université des Sciences et Technologies de Lille/CNRS Villeneuve d'A scq France
| | - Jerome Riedi
- Laboratoire d'Optique Atmosphérique-Université des Sciences et Technologies de Lille/CNRS Villeneuve d'A scq France
| | - Robert E Holz
- Cooperative Institute for Meteorological Satellite Studies University of Wisconsin-Madison Madison Wisconsin USA
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14
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Horváth Á, Seethala C, Deneke H. View angle dependence of MODIS liquid water path retrievals in warm oceanic clouds. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2014. [PMID: 25821665 DOI: 10.1002/2013jd021355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
UNLABELLED We investigated the view angle dependence of domain mean Moderate Resolution Imaging Spectroradiometer (MODIS) liquid water path (LWP) and that of corresponding cloud optical thickness, effective radius, and liquid cloud fraction as proxy for plane-parallel retrieval biases. Independent Advanced Microwave Scanning Radiometer-EOS LWP was used to corroborate that the observed variations with sun-view geometry were not severely affected by seasonal/latitudinal changes in cloud properties. Microwave retrievals showed generally small (<10%) cross-swath variations. The view angle (cross-swath) dependence of MODIS optical thickness was weaker in backscatter than forward scatter directions and transitioned from mild ∩ shape to stronger ∪ shape as heterogeneity, sun angle, or latitude increased. The 2.2 µm effective radius variations always had a ∪ shape, which became pronounced and asymmetric toward forward scatter in the most heterogeneous clouds and/or at the lowest sun. Cloud fraction had the strongest and always ∪-shaped view angle dependence. As a result, in-cloud MODIS cloud liquid water path (CLWP) showed surprisingly good view angle (cross-swath) consistency, usually comparable to that of microwave retrievals, due to cancelation between optical thickness and effective radius biases. Larger (20-40%) nadir-relative increases were observed in the most extreme heterogeneity and sun angle bins, that is, typically in the polar regions, which, however, constituted only 3-8% of retrievals. The good consistency of MODIS in-cloud CLWP was lost for gridbox mean LWP, which was dominated by the strong cloud fraction increase with view angle. More worryingly, MODIS LWP exhibited significant and systematic absolute increases with heterogeneity and sun angle that is not present in microwave LWP. KEY POINTS Microwave LWP shows small overall and cross-swath variationsMODIS in-cloud LWP also shows good view angle consistency in most casesMODIS retrievals show strong overall increase with heterogeneity and sun angle.
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Affiliation(s)
- Ákos Horváth
- Leibniz Institute for Tropospheric Research Leipzig, Germany
| | | | - Hartwig Deneke
- Leibniz Institute for Tropospheric Research Leipzig, Germany
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McBride PJ, Schmidt KS, Pilewskie P, Walther A, Heidinger AK, Wolfe DE, Fairall CW, Lance S. CalNex cloud properties retrieved from a ship-based spectrometer and comparisons with satellite and aircraft retrieved cloud properties. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017624] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Zhang Z, Ackerman AS, Feingold G, Platnick S, Pincus R, Xue H. Effects of cloud horizontal inhomogeneity and drizzle on remote sensing of cloud droplet effective radius: Case studies based on large-eddy simulations. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017655] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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King NJ, Vaughan G. Using passive remote sensing to retrieve the vertical variation of cloud droplet size in marine stratocumulus: An assessment of information content and the potential for improved retrievals from hyperspectral measurements. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017896] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Painemal D, Zuidema P. Assessment of MODIS cloud effective radius and optical thickness retrievals over the Southeast Pacific with VOCALS-REx in situ measurements. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd016155] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Zhang Z, Platnick S. An assessment of differences between cloud effective particle radius retrievals for marine water clouds from three MODIS spectral bands. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd016216] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Christensen MW, Stephens GL. Microphysical and macrophysical responses of marine stratocumulus polluted by underlying ships: Evidence of cloud deepening. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd014638] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Henrich F, Siebert H, Jäkel E, Shaw RA, Wendisch M. Collocated measurements of boundary layer cloud microphysical and radiative properties: A feasibility study. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jd013930] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- F. Henrich
- Institute for Atmospheric Physics; Johannes Gutenberg-University Mainz; Mainz Germany
| | - H. Siebert
- Leibniz Institute for Tropospheric Research; Leipzig Germany
| | - E. Jäkel
- Institute for Atmospheric Physics; Johannes Gutenberg-University Mainz; Mainz Germany
| | - R. A. Shaw
- Leibniz Institute for Tropospheric Research; Leipzig Germany
- Department of Physics; Michigan Technological University; Houghton Michigan USA
| | - M. Wendisch
- Institute for Atmospheric Physics; Johannes Gutenberg-University Mainz; Mainz Germany
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Zhang Z, Platnick S, Yang P, Heidinger AK, Comstock JM. Effects of ice particle size vertical inhomogeneity on the passive remote sensing of ice clouds. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jd013835] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Seethala C, Horváth Á. Global assessment of AMSR-E and MODIS cloud liquid water path retrievals in warm oceanic clouds. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd012662] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Coddington OM, Pilewskie P, Redemann J, Platnick S, Russell PB, Schmidt KS, Gore WJ, Livingston J, Wind G, Vukicevic T. Examining the impact of overlying aerosols on the retrieval of cloud optical properties from passive remote sensing. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd012829] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Davis SM, Avallone LM, Kahn BH, Meyer KG, Baumgardner D. Comparison of airborne in situ measurements and Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of cirrus cloud optical and microphysical properties during the Midlatitude Cirrus Experiment (MidCiX). ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd010284] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kato S, Marshak A. Solar zenith and viewing geometry-dependent errors in satellite retrieved cloud optical thickness: Marine stratocumulus case. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd010579] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Seiji Kato
- Climate Directorate; NASA Langley Research Center; Hampton Virginia USA
| | - Alexander Marshak
- Climate and Radiation Branch; NASA Goddard Space Flight Center; Greenbelt Maryland USA
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Leon DC, Wang Z, Liu D. Climatology of drizzle in marine boundary layer clouds based on 1 year of data from CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jd009835] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Platnick S, Oreopoulos L. Radiative susceptibility of cloudy atmospheres to droplet number perturbations: 1. Theoretical analysis and examples from MODIS. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009654] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Marshak A, Wen G, Coakley JA, Remer LA, Loeb NG, Cahalan RF. A simple model for the cloud adjacency effect and the apparent bluing of aerosols near clouds. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009196] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gassó S. Satellite observations of the impact of weak volcanic activity on marine clouds. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009106] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Yang Y, Di Girolamo L. Impacts of 3-D radiative effects on satellite cloud detection and their consequences on cloud fraction and aerosol optical depth retrievals. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd009095] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wang Y, Lü D, Huo J. Impact of cloud inhomogeneity on bi-directional reflectance. CHINESE SCIENCE BULLETIN-CHINESE 2008. [DOI: 10.1007/s11434-007-0434-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wen G, Marshak A, Cahalan RF, Remer LA, Kleidman RG. 3‐D aerosol‐cloud radiative interaction observed in collocated MODIS and ASTER images of cumulus cloud fields. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd008267] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Guoyong Wen
- NASA Goddard Space Flight Center Greenbelt Maryland USA
- Goddard Earth Sciences and Technology Center University of Maryland Baltimore County Baltimore County Maryland USA
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Avey L, Garrett TJ, Stohl A. Evaluation of the aerosol indirect effect using satellite, tracer transport model, and aircraft data from the International Consortium for Atmospheric Research on Transport and Transformation. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007581] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- L. Avey
- Meteorology Department; University of Utah; Salt Lake City Utah USA
| | - T. J. Garrett
- Meteorology Department; University of Utah; Salt Lake City Utah USA
| | - A. Stohl
- Norwegian Institute for Air Research; Kjeller Norway
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