We study teleparallel gravity in the original Kaluza-Klein (KK) scenario. Our calculation of the KK reduction of teleparallel gravity indicates that the 5-dimensional torsion scalar (5) T generates the non-Brans-Dicke type effective Lagrangian in 4-dimension due to an additional coupling between the derivative of the scalar field and torsion, but the result is equivalent to that in general relativity. We also discuss the cosmological behavior in the FLRW universe based on the effective teleparallel gravity.The extra dimension theory was originally proposed to unify the electromagnetism and gravity theory into one theory via 5-dimension with gauge invariant suggested by Kaluza [1].Klein then realized the Kaluza's cylindrical condition as the zero mode of harmonic expansion fields with a compactification of the 5th-dimension into a small circle S 1 [2]. In the Kaluza-Klein (KK) theory, particles are described by series of the mass spectrum, called as the KK towels. The contributions from the extra dimension give rise to the different mass scales by the KK towels. In the low energy scale, the KK dimensional reduction leads to the effective theory with gravity interacting with electromagnetic and scalar fields in 4-dimension [3].An alternative gravity theory with absolutely parallelism in Weitzenböck geometry called teleparallel equivalent to general relativity (TEGR) was first considered by Einstein [4].Recently, several generalizations related to teleparallel gravity (teleparallelism) have been presented in the literature, such as teleparallel dark energy [5] and f (T ) [6,7] models.Teleparallelism in the KK scenario has been discussed in Refs. [8][9][10][11][12]. In this article, we compute the KK reduction of TEGR at the low energy in the absence of the electromagnetic field. The reduction generates an additional non-minimal coupled term for the effective action, which matches neither with the result in Ref. [11] nor with the Brans-Dicke type theory. We also show that there exists an Einstein frame for the non-minimal teleparallel gravity by including the additional coupling. Finally, we study the flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology and discuss the solution in the KK scenario.

No abstract

No abstract

No abstract

With the development of ground-based all-sky airglow imager (ASAI) technology, a large amount of airglow image data needs to be processed for studying atmospheric gravity waves. We developed a program to automatically extract gravity wave patterns in the ASAI images. The auto-extraction program includes a classification model based on convolutional neural network (CNN) and an object detection model based on faster region-based convolutional neural network (Faster R-CNN). The classification model selects the images of clear nights from all ASAI raw images. The object detection model locates the region of wave patterns. Then, the wave parameters (horizontal wavelength, period, direction, etc.) can be calculated within the region of the wave patterns. Besides auto-extraction, we applied a wavelength check to remove the interference of wavelike mist near the imager. To validate the auto-extraction program, a case study was conducted on the images captured in 2014 at Linqu (36.2°N, 118.7°E), China. Compared to the result of the manual check, the auto-extraction recognized less (28.9% of manual result) wave-containing images due to the strict threshold, but the result shows the same seasonal variation as the references. The auto-extraction program applies a uniform criterion to avoid the accidental error in manual distinction of gravity waves and offers a reliable method to process large ASAI images for efficiently studying the climatology of atmospheric gravity waves.