More Like this

1. The Cosmic-Ray Composition between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular Mode

   https://doi.org/https://doi.org/10.3847/1538-4357/abdd30  

   Abbasi, R.U. (March 2021, The astrophysical journal)

   We report on a measurement of the cosmic-ray composition by the Telescope Array Low-energy Extension (TALE) air fluorescence detector (FD). By making use of the Cherenkov light signal in addition to air fluorescence light from cosmic-ray (CR)-induced extensive air showers, the TALE FD can measure the properties of the cosmic rays with energies as low as ~2 PeV and exceeding 1 EeV. In this paper, we present results on the measurement of $${X}_{\max }$$ distributions of showers observed over this energy range. Data collected over a period of ~4 yr were analyzed for this study. The resulting $${X}_{\max }$$ distributions are compared to the Monte Carlo (MC) simulated data distributions for primary cosmic rays with varying composition and a four-component fit is performed. The comparison and fit are performed for energy bins, of width 0.1 or 0.2 in $${\mathrm{log}}_{10}(E/\mathrm{eV})$$, spanning the full range of the measured energies. We also examine the mean $${X}_{\max }$$ value as a function of energy for cosmic rays with energies greater than 1015.8 eV. Below 1017.3 eV, the slope of the mean $${X}_{\max }$$ as a function of energy (the elongation rate) for the data is significantly smaller than that of all elements in the models, indicating that the composition is becoming heavier with energy in this energy range. This is consistent with a rigidity-dependent cutoff of events from Galactic sources. Finally, an increase in the $${X}_{\max }$$ elongation rate is observed at energies just above 1017 eV, indicating another change in the cosmic-ray composition. 

   more » « less
2. The Cosmic Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular Mode

   https://doi.org/10.3847/1538-4357/aada05  

   Abbasi, RU et (September 2018, The Astrophysical journal)
3. Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 2. Multiple‐Instrument Observations

   https://doi.org/10.1029/2019JA026797  

   Engebretson, M. J.; Steinmetz, E. S.; Posch, J. L.; Pilipenko, V. A.; Moldwin, M. B.; Connors, M. G.; Boteler, D. H.; Mann, I. R.; Hartinger, M. D.; Weygand, J. M.; et al (September 2019, Journal of Geophysical Research: Space Physics)
4. Observed changes in stratospheric circulation: decreasing lifetime of N ₂ O, 2005–2021

   https://doi.org/10.5194/acp-23-843-2023  

   Prather, Michael J.; Froidevaux, Lucien; Livesey, Nathaniel J. (January 2023, Atmospheric Chemistry and Physics)

   Abstract. Using Aura Microwave Limb Sounder satellite observationsof stratospheric nitrous oxide (N2O), ozone, and temperature from 2005through 2021, we calculate the atmospheric lifetime of N2O to bedecreasing at a rate of −2.1 ± 1.2 %/decade. This decrease is occurring because the N2O abundances in the middle tropical stratosphere, where N2O is photochemically destroyed, are increasing ata faster rate than the bulk N2O in the lower atmosphere. The causeappears to be a more vigorous stratospheric circulation, which modelspredict to be a result of climate change. If the observed trends in lifetime and implied emissions continue, then the change in N2O over the21st century will be 27 % less than those projected with a fixed lifetime, and the impact on global warming and ozone depletion will beproportionately lessened. Because global warming is caused in part byN2O, this finding is an example of a negative climate–chemistry feedback. 

   more » « less
5. Retrospect and prospect of ionospheric weather observed by FORMOSAT-3/COSMIC and FORMOSAT-7/COSMIC-2

   https://doi.org/10.1007/s44195-022-00019-x  

   Liu, Tiger Jann-Yenq; Lin, Charles Chien‐Hung; Lin, Chi‐Yen; Lee, I-Te; Sun, Yang-Yi; Chen, Shih-Ping; Chang, Fu-Yuan; Rajesh, Panthalingal Krishnanunni; Hsu, Chih-Ting; Matsuo, Tomoko; et al (December 2022, Terrestrial, Atmospheric and Oceanic Sciences)

   Abstract FORMOSAT-3/COSMIC (F3/C) constellation of six micro-satellites was launched into the circular low-earth orbit at 800 km altitude with a 72-degree inclination angle on 15 April 2006, uniformly monitoring the ionosphere by the GPS (Global Positioning System) Radio Occultation (RO). Each F3/C satellite is equipped with a TIP (Tiny Ionospheric Photometer) observing 135.6 nm emissions and a TBB (Tri-Band Beacon) for conducting ionospheric tomography. More than 2000 RO profiles per day for the first time allows us globally studying three-dimensional ionospheric electron density structures and formation mechanisms of the equatorial ionization anomaly, middle-latitude trough, Weddell/Okhotsk Sea anomaly, etc. In addition, several new findings, such as plasma caves, plasma depletion bays, etc., have been reported. F3/C electron density profiles together with ground-based GPS total electron contents can be used to monitor, nowcast, and forecast ionospheric space weather. The S4 index of GPS signal scintillations recorded by F3/C is useful for ionospheric irregularities monitoring as well as for positioning, navigation, and communication applications. F3/C was officially decommissioned on 1 May 2020 and replaced by FORMOSAT-7/COSMIC-2 (F7/C2). F7/C2 constellation of six small satellites was launched into the circular low-Earth orbit at 550 km altitude with a 24-degree inclination angle on 25 June 2019. F7/C2 carries an advanced TGRS (Tri Gnss (global navigation satellite system) Radio occultation System) instrument, which tracks more than 4000 RO profiles per day. Each F7/C2 satellite also has a RFB (Radio Reference Beacon) on board for ionospheric tomography and an IVM (Ion Velocity Meter) for measuring ion temperature, velocity, and density. F7/C2 TGRS, IVM, and RFB shall continue to expand the F3/C success in the ionospheric space weather forecasting. 

   more » « less