Aerosol size distribution models based on in situ measurements

Porter, John N.; Clarke, A. D.

doi:10.1029/96jd03403

Cited by 121 publications

(85 citation statements)

References 23 publications

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“…Two separate hypotheses surrounding each one of these factors have been advanced in the literature [Albrecht, 1989;Khain et al, 2005;Rosenfeld et al, 2008;Lee, 2012;Williams et al, 1992;Williams and Sátori, 2004;and others]. We explicitly isolate oceanic convection in the current study, but by our method it is not possible to isolate the influence of aerosols that are advected offshore downwind of major continents [e.g., Porter, 1988;Clarke et al, 1997;Porter and Clarke, 1997] and changes in environmental conditional instability. To properly address these issues, a large data set of convective scale observations is needed.…”

Section: Discussion and Future Workmentioning

confidence: 99%

Refining the relationship between lightning and convective rainfall over the ocean

Stolz

Terpstra

2014

JGR Atmospheres

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The lightning stroke density observed by Vaisala's Global Lightning Dataset (GLD360) was compared to maximum reflectivity in the upper and lower troposphere observed by NASA's Tropical Rainfall Measuring Mission Precipitation Radar over remote oceanic regions. We found that GLD360 stroke density is strongly correlated with maximum reflectivity above 0°C and the height of the 30 dBZ isopleth in two ocean basins (best represented by a logarithmic least squares regression). The maximum reflectivity above 0°C increases~8-10 dBZ and the maximum height of the 30 dBZ isopleth increases~2.8-3.8 km across the domain of stroke density. Stroke density and the maximum near-surface reflectivity are also correlated, but the range of the resulting logarithmic relationship is less than that found for maximum reflectivity above 0°C. There is high confidence in the logarithmic regressions as R 2 values are generally above 0.9 during the study. A bootstrap resampling approach confirms that the lightning versus rainfall relationship is statistically significant. Vertical profiles of radar reflectivity show that progressively larger values of stroke density are associated with higher reflectivity at most altitudes (most pronounced near 6.5 km mean sea level) and less rapid decreases in reflectivity with increasing height above 0°C. The logarithmic relationships between lightning and rainfall defined in this study have significant utility in creating proxy data sets, such as pseudoreflectivity, for weather analysis and assimilation in numerical weather prediction.

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Section: Discussion and Future Workmentioning

confidence: 99%

Refining the relationship between lightning and convective rainfall over the ocean

Stolz

Terpstra

2014

JGR Atmospheres

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“…The 28 measured ice-crystal size distributions used in Fu (1996) and the two other size distributions in Mitchell et al (1996) will be used to calculate the volume single-scattering properties of ice clouds. Two-mode lognormal size distributions (Davies, 1974;Whitby, 1978;Reist, 1984;Ott, 1990;Porter and Clarke, 1997) are applied for aerosols.…”

Section: Atmospheric Radiative Transfer Modelmentioning

confidence: 99%

Modeling polarized solar radiation from the ocean–atmosphere system for CLARREO inter-calibration applications

Sun

Lukashin

2013

Atmos. Chem. Phys.

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Abstract. Reflected solar radiance from the Earthatmosphere system is polarized. Radiance measurements can be affected by light's state of polarization if the radiometric sensor has polarization dependence. To enable the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission for inter-calibration of the imagers with polarization dependence, such as the MODIS, the polarization state of the light must be known with sufficient accuracy. For this purpose, the polarized solar radiation from the ocean-atmosphere system is studied with an adding-doubling radiative transfer model (ADRTM). The Cox-Munk ocean wave slope distribution model is used in calculation of the reflection matrix of a wind-ruffled ocean surface. An empirical foam spectral reflectance model and an empirical spectral reflectance model for water volume below the surface are integrated in the ocean-surface model. Solar reflectance from the ADRTM is compared with that from the discrete-ordinate radiative transfer (DISORT) model. Sensitivity studies are conducted for various ocean-surface and atmospheric conditions for the stratification of polarization distribution models (PDMs), which are to be used in the inter-calibration of the polarization-sensitive imager measurements with the CLARREO data. This report presents the first accurate approach for making the spectral PDMs over broad solar spectra, which cannot be achieved by empirical PDMs based on the data from polarimetric sensors.

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“…Single-scattering properties of sand-dust aerosols are calculated using agglomerated debris particles with the discrete-dipole approximation (DDA) light-scattering model (Zubko et al, 2006(Zubko et al, , 2009(Zubko et al, , 2013. Twomode lognormal size distributions (Davies, 1974;Whitby, 1978;Reist, 1984;Ott, 1990;Porter and Clarke, 1997) are applied in calculation of the single-scattering properties of aerosols. A dust aerosol refractive index of 1.5 + 0.0i is assumed in the modeling.…”

Section: Methodsmentioning

confidence: 99%

Deriving polarization properties of desert-reflected solar spectra with PARASOL data

et al. 2015

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Abstract. One of the major objectives of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) is to conduct highly accurate spectral observations to provide an on-orbit inter-calibration standard for relevant Earthobserving sensors with various channels. To calibrate an Earth-observing sensor's measurements with the highly accurate data from the CLARREO, errors in the measurements caused by the sensor's sensitivity to the polarization state of light must be corrected. For correction of the measurement errors due to the light's polarization, both the instrument's dependence on the incident polarization state and the onorbit knowledge of the polarization state of light as a function of observed scene type, viewing geometry, and solar wavelength are required. In this study, an algorithm for deriving the spectral polarization state of solar light from the desert is reported. The desert/bare land surface is assumed to be composed of two types of areas: fine sand grains with diffuse reflection (Lambertian non-polarizer) and quartz-rich sand particles with facets of various orientations (specular-reflection polarizer). The Adding-Doubling Radiative Transfer Model (ADRTM) is applied to integrate the atmospheric absorption and scattering in the system. Empirical models are adopted in obtaining the diffuse spectral reflectance of sands and the optical depth of the dust aerosols over the desert. The ratio of non-polarizer area to polarizer area and the angular distribution of the facet orientations are determined by fitting the modeled polarization states of light to the measurements at three polarized channels (490, 670, and 865 nm) by the Polarization and Anisotropy of Reflectances for Atmospheric Science instrument coupled with Observations from a Lidar (PARASOL). Based on this physical model of the surface, the desert-reflected solar light's polarization state at any wavelength in the whole solar spectra can be calculated with the ADRTM.

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Aerosol size distribution models based on in situ measurements

Cited by 121 publications

References 23 publications

Refining the relationship between lightning and convective rainfall over the ocean

Refining the relationship between lightning and convective rainfall over the ocean

Modeling polarized solar radiation from the ocean–atmosphere system for CLARREO inter-calibration applications

Deriving polarization properties of desert-reflected solar spectra with PARASOL data

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