The Relevance of the Microphysical and Radiative Properties of Cirrus Clouds to Climate and Climatic Feedback

Stephens, Graeme L.; Tsay, Si‐Chee; Stackhouse, Paul W.; Flatau, Piotr J.

doi:10.1175/1520-0469(1990)047<1742:trotma>2.0.co;2

Cited by 591 publications

(460 citation statements)

References 24 publications

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“…The importance of g in the ice optical thickness retrieval and calculation of ice radiative forcing has been demonstrated in the comparison of MODIS and POLDER ice retrievals in section 1.2, as well as in many previous studies (e.g., Stephens et al, 1990;Liou and Takano, 1994;Macke et al, 1996a;Mishchenko et al, 1996;Schlimme et al, 2005;Fu, 2007). However, only recently has the influence of the pattern of P 11 on ice optical thickness retrieval been discussed (e.g., Doutriaux-Boucher et al, 2000;C.-Labonnote et al, 2001;Knap et al, 2005;Baran and Labonnote, 2006).…”

Section: Potential Implications For the Derivation Of Seasonal Variatmentioning

confidence: 71%

Influence of ice particle model on satellite ice cloud retrieval: lessons learned from MODIS and POLDER cloud product comparison

et al. 2009

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Abstract. The influence is investigated of the assumed ice particle microphysical and optical model on inferring ice cloud optical thickness (τ ) from satellite measurements of the Earth's reflected shortwave radiance. Ice cloud τ are inferred, and subsequently compared, using products from MODIS (MODerate resolution Imaging Spectroradiometer) and POLDER (POLarization and Directionality of the Earth's Reflectances). POLDER τ values are found to be substantially smaller than those from collocated MODIS data. It is shown that this difference is caused primarily by the use of different ice particle bulk scattering models in the two retrievals, and more specifically, the scattering phase function. Furthermore, the influence of the ice particle model on the derivation of ice cloud radiative forcing (CRF) from satellite retrievals is studied. Three sets of shortwave CRF are calculated using different combinations of the retrieval and associated ice particle models. It is shown that the uncertainty associated with an ice particle model may lead to two types of errors in estimating CRF from satellite retrievals. One stems from the retrieval itself and the other is due to the optical properties, such as the asymmetry factor, used for CRF calculations. Although a comparison of the CRFs reveals that these two types of errors tend to cancel each other, significant differences are still found between the three CRFs, which indicates that the ice particle model affects notCorrespondence to: Z. Zhang (zzbatmos@umbc.edu) only optical thickness retrievals but also CRF calculations. In addition to CRF, the effect of the ice particle model on the derivation of seasonal variation of τ from satellite measurements is discussed. It is shown that optical thickness retrievals based on the same MODIS observations, but derived using different assumptions of the ice particle model, can be substantially different. These differences can be divided into two parts. The first-order difference is mainly caused by the differences in the asymmetry factor. The second-order difference is related to seasonal changes in the sampled scattering angles and therefore dependent on the sun-satellite viewing geometry. Because of this second-order difference, the use of different ice particle models may lead to a different understanding of the seasonal variation of τ .

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Section: Potential Implications For the Derivation Of Seasonal Variatmentioning

confidence: 71%

Influence of ice particle model on satellite ice cloud retrieval: lessons learned from MODIS and POLDER cloud product comparison

et al. 2009

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“…Radiative properties of mid-latitude cirrus clouds strongly depend on their microphysical parameters, e.g. ice crystal shape, size distribution and number concentration (Stephens et al, 1990;Haag and Kärcher, 2004;Fusina et al, 2007), which are influenced by ambient conditions, especially dynamics , temperature and supersaturation (Heymsfield, 1977;Khvorostyanov and Sassen, 1998b) as well as the nucleation mode, i.e. the composition of the ambient aerosol (e.g.…”

Section: Introductionmentioning

confidence: 99%

Potential of airborne lidar measurements for cirrus cloud studies

et al. 2014

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Abstract. Aerosol and water vapour measurements were performed with the lidar system WALES of Deutsches Zentrum für Luft-und Raumfahrt (DLR) in October and November 2010 during the first mission with the new German research aircraft G55-HALO. Curtains composed of lidar profiles beneath the aircraft show the vertical and horizontal distribution and variability of water vapour mixing ratio and backscatter ratio above Germany. Two missions on 3 and 4 November 2010 were selected to derive the water vapour mixing ratio inside cirrus clouds from the lidar instrument. A good agreement was found with in situ observations performed on a second research aircraft flying below HALO. ECMWF analysis temperature data are used to derive relative humidity fields with respect to ice (RHi) inside and outside of cirrus clouds from the lidar water vapour observations. The RHi variability is dominated by small-scale fluctuations in the water vapour fields while the temperature variation has a minor impact. The most frequent in-cloud RHi value from lidar observations is 98 %. The RHi variance is smaller inside the cirrus than outside of the cloud. 2-D histograms of relative humidity and backscatter ratio show significant differences for in-cloud and out-of-cloud situations for two different cirrus cloud regimes. Combined with accurate temperature measurements, the lidar observations have a great potential for detailed statistical cirrus cloud and related humidity studies.

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“…Light-scattering properties of ice crystals have been the subject of considerable work over the last few years, addressing the global climate effect of cirrus clouds (Stephens et al, 1990). Optical phenomena such as the 22 • halo (and 46 • halo) were first explained by Mariotte (1717) as being due to the refraction of light (in the visible) by randomly oriented hexagonal ice crystals.…”

Section: Introductionmentioning

confidence: 99%

Optical properties of pristine ice crystals in mid-latitude cirrus clouds: a case study during CIRCLE-2 experiment

et al. 2011

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Abstract. In this paper, we describe in situ observations of mid-latitude cirrus cloud band carried out on 16 May 2007 during the CIRCLE-2 experiment. The Polar Nephelometer and the Cloud Particle Imager (CPI) instruments with PMS FSSP-300 and 2D-C probes were used for the description of the optical and microphysical cloud properties. Two selected cloud regions are compared and discussed in detail. Significant differences in optical properties are evidenced in terms of 22 • halo occurrences even though prevalent planarplate ice crystals are observed in both cloud regions. Featureless scattering phase functions are measured in the first cloud region located near the trailing edge of the cirrus-band at about 11 800 m/−57 • C. In contrast, well pronounced 22 • halo peaks are observed with predominant similar-shaped ice crystals near the cirrus-band leading edge at 7100 m/−27 • C. CPI ice crystal images with Polar Nephelometer observations are carefully analysed and interpreted from a theoretical light scattering model in order to explain occurrence and non-occurrence of the 22 • halo feature. The results highlight that the halo peaks are inherent only in perfect plate ice crystals (or pristine crystals). On the basis of previous datasets in mid-latitude cirrus, it is found that simple pristine crystals are uncommon whereas particles with imperfect or complex shapes are prevalent. As a result, phase functions that are smooth and featureless best represent cirrus scattering properties.

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The Relevance of the Microphysical and Radiative Properties of Cirrus Clouds to Climate and Climatic Feedback

Cited by 591 publications

References 24 publications

Influence of ice particle model on satellite ice cloud retrieval: lessons learned from MODIS and POLDER cloud product comparison

Influence of ice particle model on satellite ice cloud retrieval: lessons learned from MODIS and POLDER cloud product comparison

Potential of airborne lidar measurements for cirrus cloud studies

Optical properties of pristine ice crystals in mid-latitude cirrus clouds: a case study during CIRCLE-2 experiment

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