scholarly journals Using polarimetric observations to detect and quantify the three-dimensional radiative transfer effects in passive satellite cloud property retrievals: Theoretical framework and feasibility study

Author(s):  
Chamara Rajapakshe ◽  
Zhibo Zhang
1996 ◽  
Vol 101 (D2) ◽  
pp. 4289-4298 ◽  
Author(s):  
Quanhua Liu ◽  
Clemens Simmer ◽  
Eberhard Ruprecht

2017 ◽  
Author(s):  
Rintaro Okamura ◽  
Hironobu Iwabuchi ◽  
K. Sebastian Schmidt

Abstract. Three-dimensional (3D) radiative transfer effects are a major source of retrieval errors in satellite-based optical re- mote sensing of clouds. In this study, we present two retrieval methods based on deep learning. We use deep neural networks (DNNs) to retrieve multipixel estimates of cloud optical thickness and column-mean cloud droplet effective radius simultane- ously from multispectral, multipixel radiances. Cloud field data are obtained from large-eddy simulations, and a 3D radiative transfer model is employed to simulate upward radiances from clouds. The cloud and radiance data are used to train and test the DNNs. The proposed DNN-based retrieval is shown to be more accurate than the existing look-up table approach that assumes plane-parallel, homogeneous clouds. By using convolutional layers, the DNN method estimates cloud properties robustly, even for optically thick clouds, and can correct the 3D radiative transfer effects that would otherwise affect the radiance values.


2021 ◽  
Vol 13 (2) ◽  
pp. 563
Author(s):  
Bing Ran ◽  
Scott Weller

Despite the growing utility and prevalence of social entrepreneurship, an accepted definition remains elusive and infeasible. Yet, it is imperative that the principles guiding social entrepreneurship are identified so that common ground is established to facilitate future research. On the basis of a systematic literature review, this conceptual paper proposes a theoretical framework outlining social entrepreneurship as a three-dimensional framework as a function of continua of “social” and “business” logics, “beneficial” and “detrimental” social change logics, and “innovation” and “mundane” logics. The framework accommodates the fuzziness and ambiguity associated with social entrepreneurship whilst remaining a workable, identifiable construct. By accounting for the shifting logics practiced by social entrepreneurship that both influence and are influenced by the organizational environment, this framework provides an exit strategy for the definitional elusiveness of social entrepreneurship. The resultant structures and functions of social entrepreneurship are shaped by these constraints as reflected by the fluidity and flexibility endorsed by the framework. Four avenues for future research regarding social entrepreneurship are recommended on the basis of the framework proposed in this article.


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