地球科学最新文献

Hollows on Mercury are small (hundreds of meters - few kilometers), shallow (tens of meters), irregular depressions typically found in clusters, often associated with impact craters, and likely formed by the loss of volatile materials. While their exact formation process remains debated, various hypotheses suggest sublimation or space weathering. In this study, we analyzed the global distribution of hollows, exploring their spatial patterns and relationships with key geological features. Our findings challenge the idea that hollows arise from a single volatile-rich surface layer, suggesting instead that volatiles are dispersed throughout the crust. Hollows show no correlation with specific geological units or elevations, indicating no singular volatile source. Moreover, the transitory nature of hollows is suggested as they are rare in older, degraded craters but common in younger ones or older craters with deep-seated features, hinting at a link to the reworking of materials through impacts or volcano-tectonic activity.

Correction to: Nature Climate Change https://doi.org/10.1038/s41558-024-01941-3, published online 8 March 2024.

The Tonga-Hunga volcanic eruption on 15 January 2022 at 04:14:54 UTC produced large perturbations in the lower atmosphere and ionosphere globally. We report that the long period (0.28–16.67 mHz) ionospheric disturbances followed the surface pressure perturbations, which traveled globally. Here, we analyzed the Global Positioning System (GPS) data to understand the propagation of long period ionospheric disturbances together with the pressure waves in the regions along a great circle passing through Tonga, and also in the polar sectors. We also infer the strong westward propagation of ionospheric anomalies from GPS sites in Australia. This response of the ionosphere to the surface pressure fluctuations could be a possible reason for the observed ionospheric perturbations in polar regions. Our results demonstrate that (a) the pressure wave irregularities propagated all over the globe with an average velocity of ∼320 m/s and stimulated the non-dispersive ionospheric perturbations with the same velocity, (b) the volcano ionospheric disturbances due to multiple eruptions lasted for more than 3 hr and are even noticed in the northern and southern polar regions, (c) the variation of amplitude of the ionospheric perturbations with distance from Tonga follows an exponential decay with some irregularities near the equator, and (d) a low-frequency surface pressure irregularity of 12 hr duration is observed nearly 36 hr before the main eruption.

During the boreal winter, the El Niño-Southern Oscillation (ENSO) influences the East Asia-western North Pacific (WNP) climate by triggering an anomalous WNP anticyclone (WNPAC). Analysis of a suite of coupled model projections under symmetric CO₂ ramp-up (RU) and ramp-down (RD) scenarios, the results reveal that WNPAC strengthens with increasing CO₂ concentrations, peaks early in the CO₂ RD phase, and then gradually weakens without fully returning to its initial state when CO₂ concentrations restore. The irreversible recovery of WNPAC is related to enhanced negative precipitation anomalies in the tropical WNP and positive precipitation anomalies in the equatorial central and eastern Pacific. These changed precipitation anomalies are primarily driven by the climatological equatorial Pacific El Niño-like warming pattern due to various external and internal feedback processes. Our findings indicate that the irreversible change of WNPAC to CO₂ forcing may hinder the winter monsoon and exacerbate climate risks in the East Asia-WNP region.