The Galactic cosmic-ray spectrum manifests pronounced variations over the 11 yr sunspot cycle and more subtle variations over the 22 yr solar magnetic cycle. An important tool to study these variations is repeated latitude surveys with neutron monitors (NMs) on board icebreakers in conjunction with land-based references. We revisit 13 annual latitude surveys from 1994 to 2007 using reference data from the Mawson NM instead of McMurdo NM (which closed in 2017). We then consider two more latitude surveys (2018 and 2019) with a monitor similar to the 3NM64 in the previous surveys but without lead rings around the central tube, a so-called “semi-leaded neutron monitor.” The new surveys extend the linear relationship among data taken at different cutoff rigidity ranges. They also confirm the “crossover” measured near solar minima during epochs of opposite solar magnetic polarity and the absence of a crossover for epochs having the same solar magnetic polarity.

Apart from the mechanisms of ice structure interactions under various scenarios of sea ice conditions and structural configurations, the selection of probabilistic models is crucial in order to cope with the loading uncertainty. Sea ice is the primary contributor to design loads in cold regions. In many cases, ice loads present the highest magnitude. In recent years, the probabilistic study of ice thickness, ice strength coefficient, flexural strength, ice drift speed, etc., has significantly increased, corresponding to the increasing activity of offshore operations in cold regions as well as the development of instrument technology for sea ice observation. This paper reviews existing probabilistic modes of sea ice, which are used to estimate the uncertainty of ice loading with various types of offshore structures, including vertical structures, sloping structures, and stations with floating vessels. The ISO 19906 standard is employed for the probabilistic assessment of vertical and sloping structures. The interactions between ice and structures on sloping structures are considered in both the upward and downward directions. The ice resistance method is applied for station-keeping floating vessels in ice. The key parameters of sea ice properties to estimate the design loads are studied. The effect of correlation between the key parameters of ice loads is investigated. This review shows that most existing probabilistic models are proposed for the estimation of ice loading on the various types of offshore structures.

Astronomical orientation of ancient sites can reveal astronomical wisdom utilized to resonate with the context of the maker, thus providing additional insight into that ancient culture. In this study, the orientation of Phra That Doi Suthep Temple, a sacred Buddhist temple that was founded during the prosperous period of the ancient Lanna Kingdom (in Chiang Mai, in present-day Thailand), was investigated, as well as its connection to the tradition that many Buddhists walk up the mountain to the temple on the eve of Visakha Bucha Day (Vesak Day—the Full Moon day of Vishākhā month). The remaining traces of historical evidence, including ethnic astronomical practices, suggest that the alignment of the temple when it was founded may have been related to the constellation now known as Corona Borealis (CrB), where α CrB is the reference star for the Vishākhā Nakṣhatra. To investigate this deduction, we surveyed the temple’s orientation using a theodolite and GPS, to obtain the azimuth of 59.74 ± 0.07° (30.26 ± 0.07° north of east). We employed Stellarium, which is precession-corrected, to determine the azimuth of α CrB and simulated that back in time to match that of the temple, thus yielding the estimated planning years. The finding suggests that the temple might be oriented to the true acronychal rising of α CrB in AD 1537 ± 19 in order to manifest the Full Moon on Visakha Bucha Day (a traditional Buddhist calendar’s New Year’s Day), close to the time when King Mueangketklao of Lanna reconstructed the temple on 21 April 1538.

Neutron monitors are a standard tool for high-precision monitoring of changes in the Galactic cosmic ray (GCR) flux that occur as a result of variations of the heliospheric conditions and solar storms. In Thailand, we have developed a mobile neutron monitor named “Changvan” based on the 3NM64 design, except that the middle counter lacks lead producer rings, so we call it a semileaded neutron monitor. From 2021 April to 2023 April, the Changvan operated at the Science and Technology Park, Mae Hia, Chiang Mai, Thailand, at an altitude of about 340 m above sea level, with a vertical cutoff rigidity of 16.7 GV, which is near the highest value observed globally. With a similar cutoff rigidity, the nearby Princess Sirindhorn Neutron Monitor is an 18NM64 at the summit of Doi Inthanon, the highest mountain in Thailand, at 2560 m above sea level. We examine how count rates at different altitudes with similar cutoffs, count rates from the unleaded versus leaded counters, and the leader fraction measured from time-delay histograms all reflect GCR spectral differences, thus providing a variety of techniques for tracking cosmic-ray spectral changes. Applied at high cutoff rigidity, these methods extend the reach of the worldwide neutron monitor network to even higher rigidity.