In this paper, authors propose a method for determining middle (4-7) and high (8-10) Cu amount using an unshaded pyranometer data and provide examples of its determination.
This paper describes a prototype of a multisensor oriented pyranometer designed to measure diffuse, global horizontal, and direct normal irradiance. An important feature of this pyranometer is the complete absence of any moving parts in its design. The spectral range of the measured irradiance is 0.36-2.3 μm, and the measurement range is 10-1500 W/m2.
In this paper, the authors propose a method for determining diffuse and direct irradiance under cumulus clouds using an unshaded pyranometer data, and provide an example and practical measurement results.
The results of a complex pyranometric-lidar experiment are discussed. The optical and geometric characteristics of the high-level clouds (HLCs) are estimated from the polarization laser sensing data. Scattered radiation was recorded in the near-zenith area using a zenith-directed pyranometer simultaneously with the lidar measurements. The change in the diurnal variation of the pyranometer signal at the time corresponding to the lidar registration of the HLCs with a preferred horizontal orientation of ice crystals (specular clouds) is shown.
A passive method for estimation of cloud base height using digital images is proposed. The method is based on the property of a perspective change in the angular size of an object moving parallel to the observation plane, depending on the angle of its observation. The estimation of the height of uniformly moving clouds is carried out using a sequence of images from one stationary ground-based camera directed to the zenith. To analyze one-point object, a series of three images is required. And the analysis of an extended two-point object can be carried out using a series of two images.
The results of complex lidar-actinometric experiments to study of the optical properties of high-level clouds (HLCs) and their effect on the solar radiation fluxes measured near the Earth's surface are described. Optical, microphysical (orientation of ice particles), and geometric characteristics of natural and anthropogenic (contrails) HLCs are estimated according to the data on polarization laser sensing. It is shown that the crystal orientation in cirrus affects significantly the transmission of short-wave solar radiation.
Results of the joint lidar-actinometric experiment on the study of optical properties of high-level clouds and their effect on the solar radiation fluxes measured at the Earth's surface are described. Conclusions about the effect of specular clouds on a decrease in radiation fluxes compared to non-specular ones depending on the Sun’s zenith position are drawn.
Results of the complex lidar and actinometric studies of the characteristics of cirrus containing crystalline ice particles are discussed. The greatest attention is paid to clouds consisting of horizontally oriented ensembles of ice crystals. Orientation of the crystalline particles in clouds is estimated from the backscattering phase matrix, which is determined based on the data obtained with the polarization lidar directed vertically to the zenith. Solar radiation fluxes are measured using the standard methods with an actinometer and a pyranometer. It is shown that under certain weather conditions ice crystals at altitudes of cirrus formation can be oriented horizontally, which significantly affects the transmission of solar radiation.
This paper proposes a simplified method for detecting and monitoring of clumulus clouds. The method is based on the analysis of the time series of global horizontal irradiance measured by a pyranometer. The principal feature of this method is no need to construct a model of a clear sky that is used to yield the nonstationary daily time series of global irradiance to a stationary time series.
Optical models of high-level clouds (HLCs) used for calculation of radiation fluxes in the atmosphere are analyzed briefly. Results of the experiments on polarization laser sensing of cirrus performed with the lidar developed at the National Research Tomsk State University are described. Optical and microphysical characteristics of such clouds obtained from the results of measurements of their entire backscattering phase matrices are presented. It is shown that the orientation of crystals in the cirrus significantly affects the transmission of shortwave solar radiation. This fact proves incorrectness of the representation of real crystalline particles in HLCs with spherical particles with the corresponding effective radii during calculating the Earth’s radiation budget.
In paper the device – set of hardware and software for non-contact investigation of marine particles is presented. The device is designed on digital holography principles. Hardware features of submersible holocamera (or DHC sensor) are considered. Methods are described for the processing of holograms and retrieve information. Results of approbation of the device are presented.
A complex experiment on the investigation of radiation characteristics of cirrus is performing since 2016. In the experiment, solar radiation fluxes are measured near the Earth’s surface and the orientation degree of ice crystals in cirrus is estimated using a polarization lidar. Results of the experiment are discussed. Significant effect of the orientation degree of cirrus particles on the transmission of solar radiation is found in a number of experiments.
This paper describes the multisensor oriented pyranometer with no moving parts for measuring total, direct and diffuse irradiance, and sunshine duration.
The results of the investigation of radiation characteristics of cirrus consisting of crystalline ice particles with a preferred orientation are discussed. The orientation degree of particles is estimated from the backscattering phase matrices, which are determined with the high-altitude polarization lidar developed at National Research Tomsk State University. It is shown that the orientation of ice crystals in clouds with anomalously high backscattering affects significantly the transmission of solar radiation.
Results of complex experiments, in which flows of solar radiation are measured near the Earth’s surface in the presence of cirrus cloudiness and the orientation degree of ice crystals in cirrus is estimated using a polarization lidar, are discussed. Significant effect of the orientation degree of cirrus particles on the transmission of solar radiation is found in a number of experiments.
The authors propose a method for the automated determination of cumulus clouds using the time series of direct and diffuse irradiance and their mean long-term values for a clear sky for at a given location.
The problem an estimation of influence the crystal orientation in the ice clouds on the radiation transmission is solved. The technique of synchronous measurements of total radiation with the calculation of the backscattering matrix cirrus clouds using lidar is provided.
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