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The article offers information related to tropospheric propagation in Canada from Manitoba to the central and southeastern U.S. on August 14, 2022. It informs that these openings seem to occur only every 5-7 years. It also informs that the tropospheric propagation created a new Canadian 10 GHz tropo record.

Diffusion charging of ultrafine aerosol particles is widely used in various fields and understanding the multi-physical phenomena during the charging processes is critical to the optimization of chargers and prediction of particle evolution in particulate systems. In this work, a numerical algorithm of unipolar aerosol diffusion charging is coupled with corona discharge, a combination of electric field, current continuity and heat transfer, and fluid flow enabling the modelling of multi-physics in direct charging processes. The governing equations are discretized based on the finite volume schemes. Methods of numerically calculating the ion-particle attachment coefficients are proposed and a class named niMixedFvPatchField describing the boundary condition of ion injection on the anode is defined on the basis of OpenFOAM libraries. Iteratively strategies are applied to uncouple the governing equations and the PISO (Pressure Implicit with Splitting of Operators) algorithm is used to solve the aerosol flow equations. A new solver labelled as coronaChargingFoam in the OpenFOAM framework is developed to implement the numerical algorithm and it is further validated by comparing four test cases: Laplacian electric field, electric field-charge coupling effect, ion-particle attachment coefficients, and charging efficiencies. Acceptable agreement level in all these comparisons verifies the fidelity of the solver implementation. Program Title: coronaChargingFoam CPC Library link to program files: https://doi.org/10.17632/vrfky24b8m.1 Licensing provisions: GNU General Public License (either version 3 or any later version) Programming language: C++ External routines/libraries: OpenFOAM (http://www.openfoam.org) Nature of problem: coronaChargingFoam solves the problem of aerosol charging dynamics in direct unipolar diffusion chargers in which the equations of diffusion charging are coupled with corona discharge, a combination of electric field, current continuity and heat transfer, and fluid flow enabling the modelling of multi-physics in direct charging processes. Solution method: coronaChargingFoam employs the Finite-volume method to discretize the governing equations. Iteratively strategies are applied to uncouple the multi-physical equations and the PISO algorithm is used to solve the flow fields. Simpson method and Fibonacci approach are employed in the calculation of ion-particle attachment coefficients. A new class, niMixedFvPatchField, is defined to describe the ion-injection boundary condition on the anode. Additional comments including restrictions and unusual features: The current version of the solver can only be applied in diffusion charging for monodisperse aerosol particles. This restriction will be relaxed in near future by adopting models for polydisperse particles and incorporating field charging mechanism. [ABSTRACT FROM AUTHOR]

Abstract: We present new software for the retrieval of the volume distribution – and thus, other relevant microphysical properties such as the effective radius – of stratospheric and tropospheric aerosols from multiwavelength LIDAR data. We consider the basic equation as a linear ill-posed problem and solve the linear system derived from spline collocation. We consider as well the technical implications of the algorithm implementation. In order to reduce runtime which is incurred by the vast theoretical search space, experiments on the MareNostrum Supercomputer were made to understand the significance of the different search space dimensions on the quality of the solution with the goal of restricting or eliminating entirely certain dimensions of the search space, to massively reduce calculation time for later production runs. Results show that the search space can be reduced according to available computation power to still yield reasonable results. Also, the scalability of the parallel software proved to be good. [Copyright &y& Elsevier]