Diffuse scattering model for human brain wave (Alpha) propagation prediction during meditation inside a temple, through ray tracing, a hypothetical study

Electromagnetic radio waves have been propagating for billions of years through the universe since the beginning of time. Electromagnetic radio wave propagation and the communication revolution it spawned, however are products of the twentieth century. Radio propagation in a particular environment is a complex, multipath phenomenon which involves several different mechanisms. According to a traditional, simplified approach, two major urban propagation mechanisms are identified over-roof-top (ORT) or vertical propagation (VP), where one major radial path undergoes multiple diffractions on building tops, and lateral propagation (LP) where several rays reflect/diffract all vertical building walls/edges according to the geometrical Optics (GO) rules before reaching the receiver.

Impact of October Snow Cover in Central Siberia on the Following Spring Extreme Precipitation Frequency in Southern China

Spring extreme precipitation poses great challenges to agricultural production and economic development in southern China. From the perspective of prediction, the relationship between spring extreme precipitation frequency (SEPF) in southern China and preceding autumn snow cover over Eurasia is investigated. The results indicate that the southern China SEPF is significantly correlated with October snow cover in central Siberia. Corresponding to reduced October snow cover, the vertical propagation of planetary waves is suppressed, which leads to a strengthened stratospheric polar vortex from October to following December. The signal of the anomalous stratospheric polar vortex propagates downward to the surface, contributing to a positive North Atlantic Oscillation (NAO)-like pattern in December. The southwesterlies in the northern Eurasia-eastern Arctic associated with the positive NAO induce sea ice loss in the Barents–Kara seas in January–February, which then tends to enhance the vertical propagation of planetary waves by constructively interfering with the climatological wavenumber-1 component. Therefore, the stratosphere polar vortex is significantly weakened in spring, which further contributes to a negative Arctic Oscillation (AO)-like pattern in the troposphere. The negative spring AO is related to an anomalous cyclone in East Asia, which induces upward motion and moisture convergence in southern China, consequently providing favorable dynamic and moisture conditions for extreme precipitation in the region. The snow cover signal in central Siberia in the preceding October provides a potential source for the prediction of spring extreme precipitation variability in southern China with two seasons in advance.

Propagating characteristics of mesospheric gravity waves observed by an OI 557.7 nm airglow all-sky camera at Mt. Bohyun (36.2°N, 128.9°E)

We analyzed all-sky camera images observed at Mt. Bohyun observatory (36.2°N, 128.9°E) for the period of 2017–2019. The image data were acquired with a narrow band filter centered at 557.7 nm for the OI airglow emission at ~96 km altitude. The total of 150 wave events were identified in the images of 144 clear nights. The interquartile ranges of wavelength, phase speed, and periods of the identified waves are 20.5–35.5 km, 27.4–45.0 m/s and 10.8–13.7 min with the median values of 27.8 km, 36.3 m/s and 11.7 min, respectively. The summer and spring bias of propagation directions of northeast- and northward, respectively, can be interpreted as the effect of filtering by the prevailing winds in the lower atmosphere. In winter the subdominant northwestward waves may be observed due to nullified filtering effect by small northward background wind or secondary waves generated in the upper atmosphere. Intrinsic phase speeds and periods of the waves were also derived by using the wind data simultaneously observed by a nearly co-located meteor radar. The nature of vertical propagation was evaluated in each season. The majority of observed waves are found to be freely propagating, and thus can be attributed to wave sources in the lower atmosphere.

An approach to creating application software for modeling of the deep heat processes (on the example of modeling non-stationary thermal conductivity above a mantle plume in the VLADI GEAD 4.0 MODULE)

The work substantiates the necessity and considers the methodology of own (by the researcher-modeler’s own effort) development of special applied software as a tool for modeling geological processes. The concept of a mantle plume as a system of mantle-crustal migrants, sequentially rising from the core to the fragile earth’s crust through a solid plastic mantle medium by the magma- and/or fluid fracture, is presented. A tool for computer modeling of thermal disturbance above a mantle plume in the process of its vertical development with the ability to save, process and interpret the obtained numerical and graphic information is proposed. Dependences are obtained between the depths of vertical propagation of the plume, geometric and temperature intervals of relaxation of thermal disturbance in the host medium, and geodynamic parameters. A method for assessing the thermal expansion of a medium based on the values of internal iterative variables during program execution is proposed.

Seismic analysis of a system of dam-massed foundation-reservoir under inclined excitation

One of the acceptable assumptions in engineering practice is vertical propagation of earthquake waves. When the source of earthquake is located very deep in the ground, this assumption is valid, but for sources located in shallow ground, it loses its viability. In this study, linear seismic analysis of a system of concrete dam-massed foundation-reservoir is performed under inclined earthquake excitation. Both P- and SV-type earthquakes are considered for the purpose of the seismic analysis. To consider the effects of inhomogeneous waves for the case of SV wave propagation, post-critical angles are also considered in the analysis. To investigate the effects of earthquake frequency content on the results, three different records with contents of low, intermediate, and high frequencies are selected. Results indicate that considering vertical propagation underestimates the obtained responses. For the case of SV-type earthquakes, post-critical angles must be looked at. Frequency content of the earthquake also has considerable effects on trend and absolute values of responses.