Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:p>Heatwaves are strongly associated with temperature distributions, but the mechanisms by which distributions are influenced by climate change remains unclear. Comparing simulations from a high‐spatial resolution Community Earth System Model (CESM‐HR) with those from low‐resolution models, we identify substantial improvements by CESM‐HR in reproducing observed Northern Hemisphere summer temperature skewness, as well as the frequency, intensity, persistence, and total heatwave days. Temperature skewness is strongly linked to land‐atmosphere interactions and atmospheric circulation. Under global warming projections, some regions exhibit enhanced temperature skewness, along with more frequent and persistent heatwaves of greater intensity. We find that in energy‐limited regimes, such as India, negative skewness in latent heat flux facilitates large positive skewness in sensible heat flux, which modulates near‐surface air temperatures. Skewness differences of latent and sensible heat fluxes are amplified under global warming, increasing the temperature skewness. We find that this contrasting flux mechanism is active in several heatwave‐prone regions.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Iceberg A‐68 separated from the Larsen C Ice Shelf in July 2017 and the impact of this event on the local ocean circulation has yet to be assessed. Here, we conduct numerical simulations of ocean dynamics near and below the ice shelf pre‐ and post‐calving. Results agree with in situ and remote observations of the area as they indicate that basal melt is primarily controlled by wintertime sea‐ice formation, which in turn produces High Salinity Shelf Water (HSSW). After the calving event, we simulate a 50% increase in HSSW intrusion under the ice shelf, enhancing ocean heat delivery by 30%. This results in doubling of the melt rate under Gipps Ice Rise, suggesting a positive feedback for further retreat that could destabilize the Larsen C Ice Shelf. Assessing the impact of ice‐front retreat on the heat delivery under the ice is crucial to better understand ice‐shelf dynamics in a warming environment.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Scafetta (2022, <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1029/2022gl097716">https://doi.org/10.1029/2022gl097716</jats:ext-link>) purports to test Coupled Model Intercomparison Project Phase 6 (CMIP6) climate models through a comparison of temperature changes over three decades. Unfortunately, the paper contains numerous conceptual and statistical errors that undermine all of the conclusions. First, no uncertainty is given for the observational temperature difference, making it impossible to assess compatibility with any model result. Second, the CMIP6 data are the ensemble means for each model, but the metric being tested is sensitive to the internal variability and so the full ensemble for each model must be used. When this is corrected, the conclusion that “all models with ECS &gt; 3.0°C overestimate the observed global surface warming” is not sustained. Third, the statistical test in Section 2 would reject all models even in a perfect model setup given sufficient ensemble members, thus the second conclusion “that spatial <jats:italic>t</jats:italic>‐statistics rejects the data‐model agreement” is also not sustainable.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Giant icebergs release cold, fresh meltwater as they drift, perturbing the physical conditions of the surface ocean. This study uses satellite‐derived sea surface salinity and temperature measurements to explore the physical impact of supergiant iceberg A68A between September 2020 and June 2021. During A68A's drift through the Scotia Sea in austral spring, gradual but persistent edge‐wasting contributed to a freshening of several psu extending hundreds of kilometers ahead of the iceberg, whilst the cooling signal was more pronounced in the iceberg's wake. The magnitude of the physical perturbation intensified during A68A's breakup near South Georgia. Several large meltwater lenses surrounding the descendant icebergs displayed temperature anomalies of up to −4.5°C, whilst the salinity measurements indicated a surface (skin‐depth) anomaly regularly exceeding order −10 psu. The perturbations stretched at times &gt;1,000 km and persisted for &gt;2 months following A68A's melt in April 2021.</jats:p>

<jats:title>Abstract</jats:title><jats:p>We would like to thank Wei and Shen (2023, <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1029/2022GL102596">https://doi.org/10.1029/2022GL102596</jats:ext-link>) (W23) for their comments on our recent article on GRL. In their comments, Wei and Shen argued that tremor signal on the right side of the cross‐correlation function (CCF) of PAUD‐STCD is from Kilauea crater, and they suggested that the observed time‐delay after eruption might be attributed to the noise source change and other factors. After checking the data and the code carefully, we recognize that signal on the right side of CCF of PAUD‐STCD may be due to seismicity from the Kilauea crater. However, we demonstrate here that it does not affect our conclusions.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Electron rolling‐pin distribution (RPDs), characterized by triple peaks at pitch angles 0°, 90°, and 180°, have recently been discovered in the terrestrial magnetosphere. Since the RPDs' formation is typically attributed to local betatron acceleration, RPDs have been believed to appear primarily inside strong magnetic regions, such as flux pileup regions (FPRs) behind dipolarization fronts (DFs). Different from such expectation, in this study we present unique observations of RPDs made by Cluster spacecraft in the terrestrial magnetotail, showing that RPDs are present inside weak magnetic field regions ahead of the DFs but absent in the strong magnetic field region behind them. The presence of RPD prior to the fronts may be atttributed to the combined effect of global betatron acceleration, global Fermi acceleration, and frontward transport driven by magnetic gradient drift. The atypical features of RPDs are important for fully understanding electron acceleration and transport in the magnetosphere.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Proxy reconstructions and model simulations of precipitation during Earth's glacial periods suggest that the locations and mechanisms of atmospheric moisture transport have changed considerably during Earth's past. We investigate the hydroclimate of the Last Glacial Maximum (LGM) using simulations with the Community Earth System Model, with a focus on the extratropics and the influence of atmospheric rivers (ARs), a key driver of modern‐day moisture transport globally. Mean and extreme precipitation increase significantly over southwestern Patagonia, Iberia, and southwestern North America—mid‐latitude regions affected by ARs in the modern climate—despite overall decreases elsewhere. In each, the associated moisture transport changes are different, with increased transport and AR activity mainly occurring in the North Atlantic. The overall LGM response is dominated by the response to ice sheets, with other forcings causing additional cooling and drying over the extratropics and a strong decrease of moisture transport over the subpolar North Atlantic.</jats:p>

<jats:title>Abstract</jats:title><jats:p>In 2022, western Europe experienced its hottest summer on record and widespread dry conditions, with substantial impacts on health, water and vegetation. We use a reanalysis to classify daily mean sea level pressure fields and to investigate the influence of synoptic circulations on the occurrence of temperature extremes and dry days. Summer 2022 featured an above‐normal occurrence of anticyclones extending from the British Isles to the Baltic countries, as well as enhanced easterly, southerly and low‐flow conditions which contributed to the observed extremes over southern and western Europe. While the hot summer of 2022 is only partially explained by circulation anomalies, such anomalies played a key role in the exceptional occurrence of dry days. The comparison with summer circulation anomalies projected by twenty global climate models moreover suggests that future circulation changes will further exacerbate hot and dry extremes over Europe.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Carbon release during continental rifting is thought to regulate atmospheric CO<jats:sub>2</jats:sub> levels. Supercontinent dispersal‐induced extensional tectonics is similar during the Late Ediacaran and Jurassic, while they exhibit different increases in atmospheric CO<jats:sub>2</jats:sub> concentration. The underlying mechanism of distinct CO<jats:sub>2</jats:sub> emissions remains to be understood. Here, we conduct petrological‐thermomechanical modeling to show that metamorphic decarbonation and melting of carbonates that are derived from subducted sediments are ubiquitous during continental extension. We find that the hotter lithosphere and deeper storage of these carbonates cause more significant amounts of rift‐related CO<jats:sub>2</jats:sub> release through volcanoes and faults. They may cause ∼12%–77% larger decarbonation efficiency, providing an efficient driving mechanism for a ∼31% larger increase in atmospheric CO<jats:sub>2</jats:sub> levels during the Late Ediacaran than throughout the Jurassic. The rapid eruption and deposition of recycled carbonatite volcanic ash may contribute to the production of Late Ediacaran marine carbonates with the largest negative δ<jats:sup>13</jats:sup>C (−12‰).</jats:p>

<jats:title>Abstract</jats:title><jats:p>Liu et al. (2022, <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1029/2021GL093691">https://doi.org/10.1029/2021GL093691</jats:ext-link>) used Rayleigh waves extracted from the cross‐correlation of ambient noise recorded by two stations to monitor the seismic velocity variations associated with the 2018 Kı̄lauea eruption. However, their study ignored the fact that the tremors on the Island of Hawai'i were dominated by a source at the Kı̄lauea summit before the eruption. Close inspection of the waveforms of the station pair PAUD‐STCD shows a simple, mistakenly identified wave traveling direction in Liu et al. (2022, <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1029/2021GL093691">https://doi.org/10.1029/2021GL093691</jats:ext-link>). A correct wave traveling direction agrees with the noise source model, where the dominant tremor source should be at the Kı̄lauea summit. Because of the drastic change in the tremor source after the eruption, the cross‐correlation of the tremor records may reflect predominantly changes in the source rather than in the medium properties between the two stations.</jats:p>