scholarly journals Retrieval of ice cloud properties using an optimal estimation algorithm and MODIS infrared observations: 2. Retrieval evaluation

2016 ◽  
Vol 121 (10) ◽  
pp. 5827-5845 ◽  
Author(s):  
Chenxi Wang ◽  
Steven Platnick ◽  
Zhibo Zhang ◽  
Kerry Meyer ◽  
Gala Wind ◽  
...  
Keyword(s):  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Infrared Observations ◽  
Ice Cloud ◽  
Cloud Properties

scholarly journals Inference of ice cloud properties from high spectral resolution infrared observations

2004 ◽  
Vol 42 (4) ◽  
pp. 842-853 ◽  
Author(s):  
Hung-Lung Huang ◽  
Ping Yang ◽  
Heli Wei ◽  
B.A. Baum ◽  
Yongxiang Hu ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
High Spectral Resolution ◽  
Infrared Observations ◽  
Ice Cloud ◽  
Cloud Properties

scholarly journals Retrieval of cloud properties from spectral zenith radiances observed by sky radiometers

2019 ◽  
Vol 12 (11) ◽  
pp. 6037-6047 ◽  
Author(s):  
Pradeep Khatri ◽  
Hironobu Iwabuchi ◽  
Tadahiro Hayasaka ◽  
Hitoshi Irie ◽  
Tamio Takamura ◽  
...  
Keyword(s):  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Calibration Procedure ◽  
Evaluation Study ◽  
Vapor Concentration ◽  
Observation Data ◽  
Ancillary Data ◽  
Cloud Particle ◽  
Cloud Optical Depth ◽  
Cloud Properties

Abstract. An optimal estimation algorithm to retrieve the cloud optical depth (COD) and cloud particle effective radius (CER) from spectral zenith radiances observed by narrow field-of-view (FOV) ground-based sky radiometers was developed. To further address the filter degradation problem while analyzing long-term observation data, an on-site calibration procedure is proposed, which has good accuracy compared with the standard calibration transfer method. An error evaluation study conducted by assuming errors in observed transmittances and ancillary data for water vapor concentration and surface albedo suggests that the errors in input data affect retrieved CER more than COD. Except for some narrow domains that fall within a COD of < 15, the retrieval errors are small for both COD and CER. The retrieved cloud properties reproduce the broadband radiances observed by a narrow FOV radiometer more precisely than broadband irradiances observed by a wide-FOV pyranometer, justifying the quality of the retrieved product (at least of COD) and indicating the important effect of the instrument FOV in cloud remote sensing. Furthermore, CODs (CERs) from sky radiometer and satellite observations show good (poor) agreement.

scholarly journals A test of the ability of current bulk optical models to represent the radiative properties of cirrus cloud across the mid-and far-infrared

2020 ◽  
Author(s):  
Richard J. Bantges ◽  
Helen E. Brindley ◽  
Jonathan E. Murray ◽  
Alan E. Last ◽  
Cathryn Fox ◽  
...  
Keyword(s):  
Compensation Effect ◽  
Far Infrared ◽  
Single Scattering ◽  
Radiative Properties ◽  
Cirrus Cloud ◽  
Atmospheric Measurements ◽  
Infrared Observations ◽  
Ice Cloud ◽  
Infrared Frequency Range ◽  
The Uk

Abstract. Measurements of mid- to far-infrared nadir radiances obtained from the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft during the Cirrus Coupled Cloud-Radiation Experiment (CIRCCREX) are used to assess the performance of various ice cloud bulk optical (single-scattering) property models. Through use of a minimisation approach, we find that the simulations can reproduce the observed spectra in the mid-infrared to within measurement uncertainty but are unable to simultaneously match the observations over the far-infrared frequency range. When both mid and far-infrared observations are used to minimise residuals, first order estimates of the flux differences between the best performing simulations and observations indicate a strong compensation effect between the mid and far infrared such that the absolute broadband difference is

A global record of single-layered ice cloud properties and associated radiative heating rate profiles from an A-Train perspective

2019 ◽  
Vol 53 (5-6) ◽  
pp. 3069-3088 ◽  
Author(s):  
Erica K. Dolinar ◽  
Xiquan Dong ◽  
Baike Xi ◽  
Jonathan H. Jiang ◽  
Norman G. Loeb ◽  
...  
Keyword(s):  
Heating Rate ◽  
Radiative Heating ◽  
Ice Cloud ◽  
Cloud Properties

scholarly journals Effect of Aerosols on the Ice Cloud Properties Over the Tibetan Plateau

2019 ◽  
Vol 124 (16) ◽  
pp. 9594-9608 ◽  
Author(s):  
Yuzhi Liu ◽  
Shan Hua ◽  
Rui Jia ◽  
Jianping Huang
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Ice Cloud ◽  
Cloud Properties

scholarly journals Synergy of stereo cloud top height and ORAC optimal estimation cloud retrieval: evaluation and application to AATSR

2016 ◽  
Vol 9 (3) ◽  
pp. 909-928 ◽  
Author(s):  
Daniel Fisher ◽  
Caroline A. Poulsen ◽  
Gareth E. Thomas ◽  
Jan-Peter Muller
Keyword(s):  
A Priori ◽  
Single Layer ◽  
Optimal Estimation ◽  
Open Water ◽  
A Priori Information ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Priori Information ◽  
Cloud Parameter ◽  
The Impact

Abstract. In this paper we evaluate the impact on the cloud parameter retrievals of the ORAC (Optimal Retrieval of Aerosol and Cloud) algorithm following the inclusion of stereo-derived cloud top heights as a priori information. This is performed in a mathematically rigorous way using the ORAC optimal estimation retrieval framework, which includes the facility to use such independent a priori information. Key to the use of a priori information is a characterisation of their associated uncertainty. This paper demonstrates the improvements that are possible using this approach and also considers their impact on the microphysical cloud parameters retrieved. The Along-Track Scanning Radiometer (AATSR) instrument has two views and three thermal channels, so it is well placed to demonstrate the synergy of the two techniques. The stereo retrieval is able to improve the accuracy of the retrieved cloud top height when compared to collocated Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), particularly in the presence of boundary layer inversions and high clouds. The impact of the stereo a priori information on the microphysical cloud properties of cloud optical thickness (COT) and effective radius (RE) was evaluated and generally found to be very small for single-layer clouds conditions over open water (mean RE differences of 2.2 (±5.9) microns and mean COD differences of 0.5 (±1.8) for single-layer ice clouds over open water at elevations of above 9 km, which are most strongly affected by the inclusion of the a priori).

scholarly journals Investigation of ice particle habits to be used for ice cloud remote sensing for the GCOM-C satellite mission

2016 ◽  
Vol 16 (18) ◽  
pp. 12287-12303 ◽  
Author(s):  
Husi Letu ◽  
Hiroshi Ishimoto ◽  
Jerome Riedi ◽  
Takashi Y. Nakajima ◽  
Laurent C.-Labonnote ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Asymmetry Factor ◽  
Size Parameter ◽  
Geometric Optics ◽  
Ice Clouds ◽  
Extinction Efficiency ◽  
Ice Cloud ◽  
Cloud Properties

Abstract. In this study, various ice particle habits are investigated in conjunction with inferring the optical properties of ice clouds for use in the Global Change Observation Mission-Climate (GCOM-C) satellite programme. We develop a database of the single-scattering properties of five ice habit models: plates, columns, droxtals, bullet rosettes, and Voronoi. The database is based on the specification of the Second Generation Global Imager (SGLI) sensor on board the GCOM-C satellite, which is scheduled to be launched in 2017 by the Japan Aerospace Exploration Agency. A combination of the finite-difference time-domain method, the geometric optics integral equation technique, and the geometric optics method is applied to compute the single-scattering properties of the selected ice particle habits at 36 wavelengths, from the visible to the infrared spectral regions. This covers the SGLI channels for the size parameter, which is defined as a single-particle radius of an equivalent volume sphere, ranging between 6 and 9000 µm. The database includes the extinction efficiency, absorption efficiency, average geometrical cross section, single-scattering albedo, asymmetry factor, size parameter of a volume-equivalent sphere, maximum distance from the centre of mass, particle volume, and six nonzero elements of the scattering phase matrix. The characteristics of calculated extinction efficiency, single-scattering albedo, and asymmetry factor of the five ice particle habits are compared. Furthermore, size-integrated bulk scattering properties for the five ice particle habit models are calculated from the single-scattering database and microphysical data. Using the five ice particle habit models, the optical thickness and spherical albedo of ice clouds are retrieved from the Polarization and Directionality of the Earth's Reflectances-3 (POLDER-3) measurements, recorded on board the Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar (PARASOL) satellite. The optimal ice particle habit for retrieving the SGLI ice cloud properties is investigated by adopting the spherical albedo difference (SAD) method. It is found that the SAD is distributed stably due to the scattering angle increases for bullet rosettes with an effective diameter (Deff) of 10 µm and Voronoi particles with Deff values of 10, 60, and 100 µm. It is confirmed that the SAD of small bullet-rosette particles and all sizes of Voronoi particles has a low angular dependence, indicating that a combination of the bullet-rosette and Voronoi models is sufficient for retrieval of the ice cloud's spherical albedo and optical thickness as effective habit models for the SGLI sensor. Finally, SAD analysis based on the Voronoi habit model with moderate particle size (Deff = 60 µm) is compared with the conventional general habit mixture model, inhomogeneous hexagonal monocrystal model, five-plate aggregate model, and ensemble ice particle model. The Voronoi habit model is found to have an effect similar to that found in some conventional models for the retrieval of ice cloud properties from space-borne radiometric observations.

scholarly journals Ice cloud microphysical trends observed by the Atmospheric Infrared Sounder

2018 ◽  
Author(s):  
Brian H. Kahn ◽  
Hanii Takahashi ◽  
Graeme L. Stephens ◽  
Qing Yue ◽  
Julien Delanoë ◽  
...  
Keyword(s):  
Strong Dependence ◽  
Surface Wind ◽  
Single Layer ◽  
Particle Growth ◽  
Surface Wind Speed ◽  
Ice Cloud ◽  
Cloud Properties ◽  
Strong Convection ◽  
Ice Water ◽  
Cloud Top Temperature

Abstract. We use the AIRS version 6 ice cloud property and thermodynamic phase retrievals to quantify variability and 14-year trends in ice cloud frequency, ice cloud top temperature (Tci), ice optical thickness (τi) and ice effective radius (rei). The trends in ice cloud properties are shown to be independent of trends in information content and χ2. Statistically significant decreases in ice frequency, τi, and ice water path (IWP) are found in the SH and NH extratropics, but trends are much smaller and statistically insignificant in the tropics. However, statistically significant increases in rei are found in all three latitude bands. Perturbation experiments consistent with estimates of AIRS radiometric stability fall significantly short of explaining the observed trends in ice properties, averaging kernels, and χ2 trends. Values of rei are larger at the tops of opaque clouds and exhibit strong dependence on surface wind speed, column water vapour (CWV) and surface temperature (Tsfc) with changes up to 10–12 μm. Transparent clouds exhibit a much smaller change in rei for CWV, while none is observed for Tsfc. Comparisons between DARDAR and AIRS suggest that rei is smallest for single-layer cirrus, larger for cirrus above weak convection, and largest for cirrus above strong convection at the same cloud top temperature. This behaviour is consistent with enhanced particle growth from radiative cooling above convection or large particle lofting from strong convection.

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