Abstract: King penguins (Aptenodytes patagonicus Miller) are major consumers in the Southern Ocean. The colony at Ile aux Cochons, Iles Crozet, in the southern Indian Ocean was known in the 1980s as the largest king penguin colony and the second largest penguin colony in the world. However, there have not been any recent estimates of this colony. Aerial photographs taken from a helicopter, and satellite images were used to report on changes in the colony and population sizes over the past 50 years. The colony has declined by 88% over the past 35 years, from c. 500 000 pairs to 60 000 pairs. The possible causes of this decline were explored but no plausible explanation for such an unprecedented decrease in penguin populations was found. The study highlights the use of satellite imagery as a non-invasive technique for population monitoring, and stresses the need for further research on the causes of this alarming trend in this colony.

Abstract: Several applications exist that calculate cosmic-ray-induced particle (CRIP) spectra as a function of the altitude in the atmosphere. In general, the Earth's magnetic field is only used to modulate the primary cosmic radiation that arrives at the top of the atmosphere, but it can also modulate low-energy charged particles at flight altitudes. The effects of the Earth's magnetic field on the angular distributions of CRIP transport in the atmosphere should be quantified, because it furnishes important data for the development of applications for aircrew radiation protection, onboard dosimetry and the simulation of irradiation of sensitive equipment and particle detector systems used at ground level, flight and atmospheric balloon altitudes. In this work we calculate the angular distribution of the cosmic-ray-induced particles (CRIP) for altitudes from ground level up to 80?km using an application based on Geant4 developed in previous works. In order to quantify the effects of the Earth's magnetic field (EMF) on the angular distribution of the CRIP, the calculations were carried out both including the EMF in the South Atlantic Magnetic region and omitting it. A part of these results were compared with analytical calculations of the ratio between the mean free path of the primary particles from the cosmic radiation and the deflection radii at different altitudes in the atmosphere. The albedos of neutrons and protons at 80?km were estimated and compared with the QARM and ATMORAD codes, which ignore the Earth's magnetic field.

Abstract: Several applications exist that calculate cosmic-ray-induced particle (CRIP) spectra as a function of the altitude in the atmosphere. In general, the Earth's magnetic field is only used to modulate the primary cosmic radiation that arrives at the top of the atmosphere, but it can also modulate low-energy charged particles at flight altitudes. The effects of the Earth's magnetic field on the angular distributions of CRIP transport in the atmosphere should be quantified, because it furnishes important data for the development of applications for aircrew radiation protection, onboard dosimetry and the simulation of irradiation of sensitive equipment and particle detector systems used at ground level, flight and atmospheric balloon altitudes. In this work we calculate the angular distribution of the cosmic-ray-induced particles (CRIP) for altitudes from ground level up to 80?km using an application based on Geant4 developed in previous works. In order to quantify the effects of the Earth's magnetic field (EMF) on the angular distribution of the CRIP, the calculations were carried out both including the EMF in the South Atlantic Magnetic region and omitting it. A part of these results were compared with analytical calculations of the ratio between the mean free path of the primary particles from the cosmic radiation and the deflection radii at different altitudes in the atmosphere. The albedos of neutrons and protons at 80?km were estimated and compared with the QARM and ATMORAD codes, which ignore the Earth's magnetic field.