Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:p>Based on the predictions of global 3D hybrid simulations, we present a new transport/acceleration path for escaped O<jats:sup>+</jats:sup> ions in the upstream solar wind region resulting from the impact of a particular IMF tangential discontinuity (TD) with negative (positive) IMF <jats:italic>B</jats:italic><jats:sub>z</jats:sub> on the discontinuity's anti‐sunward (sunward) side. For O<jats:sup>+</jats:sup> ions escaping to the duskside magnetosheath and with gyro‐radii larger than the TD thickness, when they encounter the TD, they can first go sunward into the upstream solar wind. They then gyrate clockwise to the pre‐noon side and get accelerated within the solar wind region and circulate back to the dawnside magnetosphere. These ions may be accelerated to well within the ring current energy range depending on the solar wind electric field strength. This new transport/acceleration path can bring some of the escaped ions into the inner magnetosphere, thus providing a new mechanism for generating an O<jats:sup>+</jats:sup> ring current population.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Understanding the regional climate response to land cover change requires a realistic sub‐grid representation of vegetation cover in the land surface scheme (LSS) of climate models. The Community Land Model (CLM) is considered one of the most advanced LSSs; however, when coupled with the Weather Research and Forecasting (WRF) model, the tiling vegetation cover approach was deactivated. Here, we reactivated the theoretical sub‐grid vegetation cover representation in WRF‐CLM and applied it to assess the impacts of deforestation on regional climate in the Southeast Asian Massif region. We found that CLM‐tiling performs more accurate simulations of surface air temperature and precipitation compared to other LSSs using the in situ observations. Importantly, CLM‐tiling successfully captures the theoretical sensitivity of evapotranspiration (ET) and temperature to sub‐grid deforestation, aligning with Noah‐mosaic, and it substantially improves the spatial pattern responses of simulated ET and temperature to regional deforestation.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Cloud feedbacks are the leading cause of uncertainty in climate sensitivity. The complex coupling between clouds and the large‐scale circulation in the tropics contributes to this uncertainty. To address this problem, the coupling between clouds and circulation in the latest generation of climate models is compared to observations. Significant biases are identified in the models. The implications of these biases are assessed by combining observations of the present day with future changes predicted by models to calculate observationally constrained feedbacks. For the dynamic cloud feedback (i.e., due to changes in circulation), the observationally constrained values are consistently larger than the model‐only values. This is due to models failing to capture a nonlinear minimum in cloud brightness for weakly descending regimes. Consequently, while the models consistently predict that these regimes increase in frequency in association with a weakening tropical circulation, they underestimate the positive cloud feedback associated with this increase.</jats:p>

<jats:title>Abstract</jats:title><jats:p>We deployed a dense geodetic and seismological network in the Atacama seismic gap in Chile. We derive a microseismicity catalog of &gt;30,000 events, time series from 70 GNSS stations, and utilize a transdimensional Bayesian inversion to estimate interplate locking. We identify two highly locked regions of different sizes whose geometries appear to control seismicity patterns. Interface seismicity concentrates beneath the coastline, just downdip of the highest locking. A region with lower locking (27.5°S–27.7°S) coincides with higher seismicity levels, a high number of repeating earthquakes and events extending toward the trench. This area is situated where the Copiapó Ridge is subducted and has shown previous indications of both seismic and aseismic slip, including an earthquake sequence in 2020. While these findings suggest that the structure of the downgoing oceanic plate prescribes patterns of interplate locking and seismicity, we note that the Taltal Ridge further north lacks a similar signature.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The substorm current wedge (SCW), the characteristic current system of Earth's substorms, has been suggested to be a collective effect of many “wedgelets,” mesoscale currents carried by magnetotail flux tubes of strong magnetic fields called dipolarizing flux bundles (DFBs). Each wedgelet contains an asymmetric pair of field‐aligned currents (FACs) so the net FAC of many wedgelets can equal an SCW's FAC content. It is unclear, however, why a wedgelet's FAC is asymmetric. To explore the reason, we investigate how earthward‐traveling DFBs interact with ambient plasma because this interaction leads to their FACs. The interaction is manifested as the pressure and magnetic field distributions around DFBs, which we examine statistically using THEMIS data. The statistical distributions are consistent with an interplay between the DFB‐caused mesoscale perturbations and the global magnetotail configuration and favor the rise of wedgelets' asymmetric FACs. This result reveals the importance of cross‐scale coupling in SCW formation.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The cold ions, which are generally “invisible” to most instruments, have strong impacts on plasma wave and magnetic reconnection. Under particular situations, these cold ions could be accelerated and thus become detectable. In this study, we statistically investigated the properties of background cold ions based on Van Allen Probe observations. The cold ions could often be detected near the dusk sector, and a clear dawn‐dusk asymmetry is observed for all ion species with higher density at the dusk side, showing plasmaspheric plume‐like structures. Similar to the cold electrons, cold proton ions show a clear boundary of plasmapause with its location moving toward the Earth as geomagnetic activity increases. Furthermore, the percentage of oxygen increases, and the percentage of protons decreases as geomagnetic activity increases whereas the helium composition is generally small. Our results provide important information on ion compositions for the understanding of cold‐plasma dynamics in the inner magnetosphere.</jats:p>