GRAPES-3 is a mid-altitude (2200 m) and near-equatorial (11.°4N) air shower array, overlapping in its field of view for cosmic-ray observations with experiments that are located in the Northern and Southern Hemispheres. We analyze a sample of 3.7 × 10⁹ cosmic-ray events collected by the GRAPES-3 experiment between 2013 January 1 and 2016 December 31 with a median energy of ∼16 TeV for study of small-scale (<60°) angular-scale anisotropies. We observed two structures, labeled A and B, that deviate from the expected isotropic distribution of cosmic rays in a statistically significant manner. Structure A spans 50°–80° in R.A. and from −15° to 30° in decl. The relative excess observed in structure A is at the level of (6.5 ± 1.3) × 10⁻⁴ with a statistical significance of 6.8 standard deviations. Structure B is observed in the R.A. range 110°–140° and at decl. from −10° to 30°. The relative excess observed in this region is at the level of (4.9 ± 1.4) × 10⁻⁴ with a statistical significance of 4.7 standard deviations. These structures are consistent with those reported by Milagro, ARGO-YBJ, and HAWC. These observations could provide a better understanding of the sources of cosmic rays, their propagation, and the magnetic structures in our Galaxy.

Thunderstorms, lightning, and the Global Electric Circuit (GEC) are interconnected, and their studies have significant implications for understanding the global climate. Solar insolation plays a role in linking lightning distribution to Earth's climate. Extensive research on the GEC has aimed to establish a connection between variations in the fair-weather electric field (known as the Carnegie curve) and global variations in electrified weather, using lightning rates as a proxy. Thunderstorm-induced muon events (TIMEs) are observed when strong electric fields in thunderstorms modulate muon acceleration, leading to changes in their count rate at the observational level. In this study, we report a substantial number of TIMEs observed continuously over a fifteen-year period (2006-2020). Furthermore, we examine the diurnal distribution patterns of these events by comparing them with the Carnegie curve. The observed comparative pattern stimulates contemplation about the relationship between the GEC and TIMEs and suggests the former's potential role in the formation of the latter.