The polarization of light scattered by small particles: A personal review

Hovenier, J. W.

doi:10.1016/j.jqsrt.2012.03.029

Cited by 8 publications

(4 citation statements)

References 69 publications

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“…Both solar and thermal sources of radiation are considered. The extinction coefficients, scattering coefficients, and the phase matrix information of liquid cloud particles are precalculated based on the Lorenz-Mie code of Bohren and Huffman (1983), where the phase matrix information is described in the form of coefficients for Legendre polynomial expansions (Hansen and Travis, 1974;Hovenier, 2012;Hovenier and Van der Mee, 1983). This information and the cloud layer height are loaded into RT3 from a precalculated file.…”

Section: Polder-like Observations Simulated With the Rt3 Modelmentioning

confidence: 99%

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-like Observations Simulated With the Rt3 Modelmentioning

confidence: 99%

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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show abstract

“…The formats and styles of the Van de Hulst Lecture and the Van de Hulst Essay are still in a state of flux since only two such lectures have been presented and only one such Essay has been published [1]. On one hand, this lack of established traditions appears to represent a challenge.…”

Section: Introductionmentioning

confidence: 99%

“…As already mentioned, I owe my initial basic knowledge of the theory of radiative transfer to Van de Hulst's monograph [3], as well as to the so-called "blue Sobolev" [9]. 1 That nickname refers to the navy blue color of the cover in the original Russian edition of this well-known monograph and was used by Soviet scientists to distinguish it casually from the "black Sobolev" [11]. As a novice in the field of radiative transfer, I took for granted the apparent simplicity and obviousness of the main phenomenological concepts of this discipline and for some time had not realized that the "traditional" radiative transfer theory (RTT) is, figuratively speaking, a "colossus with feet of clay".…”

Section: Introductionmentioning

confidence: 99%

“…Joop Hovenier (left) and Michael Mishchenko at ELS-XIV in Lille on 17 June 2013. 1 Another essential source was the famous review by my future colleagues at GISS James Hansen and Larry Travis [10]. This paper was immensely popular among my Soviet colleagues despite the fact that only a few preprints and even fewer reprints were in circulation.…”

Section: Introductionmentioning

confidence: 99%

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