Search
Now showing items 1-10 of 38
Linear polarization signatures of atmospheric dust with the SolPol direct-sun polarimeter
(2023-10-12)
Dust particles in lofted atmospheric layers may present a preferential orientation, which could be detected from the resulting dichroic extinction of the transmitted sunlight. The first indications were provided relatively ...
Monitoring dust particle orientation with measurements of sunlight dichroic extinction
(2021-09-29)
Alignment of irregularly shaped dust aerosols leading to linear dichroism has been reported in atmospheric layers. The present study intents to quantify the excess linear polarization of direct solar radiation propagating ...
Measurement report: Balloon-borne in-situ profiling of Saharan dust over Cyprus with the UCASS optical particle counter
(2021-05-05)
This paper presents measurements of mineral dust concentration in the diameter range from 0.4 to 14.0 μm with a novel balloon-borne optical particle counter, the Universal Cloud and Aerosol Sounding System (UCASS). The ...
Halo ratio from ground based all-sky imaging
(2019-02-28)
The halo ratio (HR) is a quantitative measure characterizing the occurrence of the 22 halo peak associated with cirrus. We propose to obtain it from an approximation to the scattering phase function (SPF) derived from ...
Discussion of a physical optics method and its application to absorbing smooth and slightly rough hexagonal prisms
(2018-10-01)
Three different mathematical solutions of a physical optics model for far field diffraction by an aperture due to Karczewski and Wolf are discussed. Only one of them properly describes diffraction by an aperture and can, ...
Surface roughness during depositional growth and sublimation of ice crystals
(2018-09-27)
Ice surface properties can modify the scattering properties of atmospheric ice crystals and therefore affect the radiative properties of mixed-phase and cirrus clouds. The Ice Roughness Investigation System (IRIS) is a new ...
Studies on mineral dust using airborne lidar, ground-based remote sensing, and in situ instrumentation
(2018-04-13)
In August 2015, the AER-D campaign made use of the FAAM research aircraft based in Cape Verde, and targeted mineral dust. First results will be shown here. The campaign had multiple objectives: (1) lidar dust mapping for ...
Characterizing ice particles using two-dimensional reflections of a lidar beam
(2017-07-01)
We report a phenomenon manifesting itself as brief flashes of light on the snow surface near a lidar beam. The flashes are imaged and interpreted as specular reflection patterns from individual ice particles. Such patterns ...
Cloud Ice Properties: In Situ Measurement Challenges
(2017-04-10)
Understanding the formation and evolution of ice in clouds requires detailed information on the size, shape, mass and optical properties of individual cloud hydrometeors and their bulk properties over a broad range of ...
Cirrus clouds
(2017)
The goal of this article is to synthesize information about what is now known about one of the three main types of clouds, cirrus, and to identify areas where more knowledge is needed. Cirrus clouds, composed of ice ...