地球科学最新文献

{"title":"The Radio Wave Polarization of Saturn Lightning Observed by Cassini","authors":"G. Fischer,&nbsp;M. Imai,&nbsp;U. Taubenschuss,&nbsp;D. Píša,&nbsp;W. S. Kurth","doi":"10.1029/2024JA033560","DOIUrl":"https://doi.org/10.1029/2024JA033560","url":null,"abstract":"<p>We investigate the polarization of the radio waves emitted by lightning in Saturn's atmosphere, which are referred to as SEDs for Saturn Electrostatic Discharges. Using the complete SED data set retrieved by Cassini's RPWS (Radio and Plasma Wave Science) instrument we found that the circular polarization of SEDs below a frequency of 2 MHz depends on the latitudinal hemisphere of the lightning storm. SEDs from several storms located at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>35</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $35{}^{circ}$</annotation>\u0000 </semantics></math> South latitude display a strong right–hand sense of circular polarization, whereas SEDs from storms located at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>35</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $35{}^{circ}$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>50</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $50{}^{circ}$</annotation>\u0000 </semantics></math> North are overwhelmingly left–hand polarized. A single storm located at Saturn's equator in June 2005 shows 4 right–handed SEDs when Cassini was in the northern hemisphere and 4 left–handed SEDs when Cassini was in the southern hemisphere. The polarization characteristic is consistent with an emission in the L-O mode, consistent with the theory of Fischer, Gurnett, et al. (2007, JGR 112, A12308, https://doi.org/10.1029/2007JA012592) that the R-X mode is largely absorbed in Saturn's ionosphere below a frequency of 2 MHz. The sense of circular SED polarization below 2 MHz is opposite to the polarization of Saturn kilometric radiation (SKR), and thus this can be used to distinguish SEDs from SKR and to determine the hemispherical origin of the causative lightning storm.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033560","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The First Instrumentally Detected Hydrothermal Explosion in Yellowstone National Park","authors":"Michael P. Poland,&nbsp;Alexandra M. Iezzi,&nbsp;Jamie Farrell,&nbsp;R. Greg Vaughan","doi":"10.1029/2025GL115850","DOIUrl":"https://doi.org/10.1029/2025GL115850","url":null,"abstract":"<p>Hydrothermal explosions are one of the geological hazards most likely to impact people in Yellowstone National Park, but their frequency is poorly known. Infrasound and seismic sensors identified an explosion in Norris Geyser Basin on 15 April 2024, at 14:56 MDT (20:56 UTC)—the first instrumentally detected hydrothermal explosion in the Yellowstone region. The event affected an area tens of meters across, resulting in fractured ground, a shallow explosion crater, and a field of ejecta. There were no immediate geophysical precursors, but in the preceding years elevated discharge of thermal water altered the color, temperature, and level of a nearby small lake. Expanded seismo-acoustic monitoring in Yellowstone National Park could be useful for detecting small hydrothermal explosions and constraining their frequency, magnitude, energy release, and locations—information that could be used to better assess and mitigate hazards for the millions of people that visit the park each year.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"52 11","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GL115850","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Filling the gap of the late Quaternary planktonic foraminifera record in the Western Mediterranean: Paleoceanographic changes in the Ligurian Sea over the last 27.4 ka","authors":"Pierluigi Martinelli ,&nbsp;Laura Bronzo ,&nbsp;Sergio Bonomo ,&nbsp;Isabel Cacho ,&nbsp;Antonio Cascella ,&nbsp;Letizia Di Bella ,&nbsp;José-Abel Flores ,&nbsp;Jaime Frigola ,&nbsp;Fabrizio Lirer ,&nbsp;Fabrizio Michelangeli ,&nbsp;Mar Selvaggi ,&nbsp;Francisco J. Sierro ,&nbsp;Rocco Gennari","doi":"10.1016/j.palaeo.2025.113078","DOIUrl":"10.1016/j.palaeo.2025.113078","url":null,"abstract":"<div><div>This study aims to expand our understanding of the paleoceanographic changes in the western Mediterranean during the Late Quaternary by investigating the planktonic foraminifera and the reworked coccolith records of the NDT_22_2016 core (27.4 ka cal BP to present) in the Ligurian Sea. To achieve this a robust age model was developed using 17 radiocarbon dates, allowing sub-millennial resolution analyses. The last glacial period (115–11.7 ka cal BP) was characterized by cold-eutrophic species (<em>Globigerinita glutinata, Globigerina bulloides</em> and <em>Turborotalita quinqueloba</em>), while formation of a seasonal deep chlorophyll maximum (DCM) was confined to the south-western Mediterranean as testified by the distribution of <em>Neogloboquadrina incompta</em>. The intervening Heinrich events were identified in the Ligurian Sea through reworked coccolith peaks and the subsequent increase of <em>N. incompta</em>, indicating enhanced runoff and DCM formation, respectively, in response to a northward expansion of the summer warming. Subsequently, during deglaciation, intense warming initiating with the Bølling-Allerød, and interrupted during the Younger Dryas, led to an increase in the abundance of <em>Globoconella inflata</em>, suggesting year-round stratification. The Holocene was subdivided in three phases: an initial rapid warming (up to 10.4 ka cal BP), followed by the development of strong stratification during the second phase (10.4–5.3 ka cal BP), which includes the time interval of sapropel S1 in the Eastern Mediterranean. The second to third phase transition is marked by the appearance of <em>Globorotalia truncatulinoides</em>, signalling a strong seasonal contrast, characterized by strong winter mixing and summer stratification as evidenced also by the presence of <em>N. incompta</em>.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"675 ","pages":"Article 113078"},"PeriodicalIF":2.6,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of hydrological processes on the benthic macroinvertebrate biodiversity in floodplain wetlands: A regional study of Poyang lake","authors":"Siyang Yao ,&nbsp;Xinyuan Liu ,&nbsp;Jutao Liu ,&nbsp;Siyu Wan","doi":"10.1016/j.ejrh.2025.102509","DOIUrl":"10.1016/j.ejrh.2025.102509","url":null,"abstract":"<div><h3>Study region</h3><div>Poyang Lake, China's largest freshwater lake and a renowned floodplain wetland, is enlisted in the Ramsar Convention.</div></div><div><h3>Study focus</h3><div>The hydrological process (HP), a vital part of the hydrological regime, notably affects biodiversity patterns in floodplain wetlands. However, the pathways through which hydrological process impacts the benthic macroinvertebrate biodiversity remain ambiguous.</div></div><div><h3>New hydrological insights for the region</h3><div>Across the rising, flooding, and falling water level stages, HP indicators exhibited diverse relationships with biodiversity. During the rising and falling stages, the relationship manifested as an inverted U-shaped trend; in the flooding stage, the biodiversity exhibited a U-shaped decreasing trend. The impact of HPs on biodiversity was complex. In the rising stage, the HP exerted a direct influence on biodiversity, with a path coefficient of −0.633. Additionally, it indirectly affected biodiversity through water quality indicators, with an indirect path coefficient of −0.773. In the flooding stage, the HP exerted an indirect influence on biodiversity via water temperature and landscape indicators, with the corresponding path coefficients of 0.185 and −0.367, respectively. During the falling stage, the HP directly affected biodiversity, as indicated by a path coefficient of −0.564, and also indirectly influenced it through water temperature, with an indirect path coefficient of −0.799. Overall, the indirect effect was more prominent in the rising and falling stages, while the direct impact was insignificant in the flooding stage.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"60 ","pages":"Article 102509"},"PeriodicalIF":4.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishing a Statistical Framework for Assessing Paleomagnetic Data Quality: A Significance Test Based on Maximum Angular Deviation","authors":"D. Heslop,&nbsp;A. P. Roberts","doi":"10.1029/2025JB031417","DOIUrl":"https://doi.org/10.1029/2025JB031417","url":null,"abstract":"<p>Paleomagnetic data underpin our understanding of Earth's ancient magnetic field and are essential to paleogeographic reconstructions. At the specimen level, paleomagnetic analysis relies upon stepwise demagnetization to enable isolation and quantification of magnetic remanence components in geological materials. This quantification is performed typically using principal component analysis (PCA) to fit a line to stepwise demagnetization data. The quality of such PCA fits is assessed via the so-called maximum angular deviation (MAD), which is used in a heuristic fashion to represent directional uncertainty and as a selection criterion for identifying poorly or well behaved specimens. We present here a significance test that employs MAD as a statistic to compare demagnetization data against a null hypothesis of random behavior. This places MAD within a formal statistical framework that can be used to test the quality of demagnetization data before undertaking more detailed analysis. Tables of numerically estimated significance levels are provided to enable ready application of the proposed test and recommendations are made concerning the number of demagnetization data needed for statistical inference.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031417","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144232441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deciphering the capricious precipitation response: irrigation impact in the North China Plain","authors":"Yuwen Fan, Zhao Yang, Min-Hui Lo, Jina Hur, Eun-Soon Im","doi":"10.1038/s41612-025-01063-3","DOIUrl":"https://doi.org/10.1038/s41612-025-01063-3","url":null,"abstract":"<p>Intensive irrigation in the North China Plain (NCP) raises environmental concerns, yet its climate impacts remain inconsistent among current modeling studies. These inconsistencies may arise from deficiencies in existing models. To better capture irrigation impact, we employed a recently improved irrigation model tailored for the NCP, which significantly enhances simulations of crop growth and irrigation application. Results reveal that irrigation exerts competing effects on precipitation: enhancing it in May and June by increasing rainfall frequency and intensity, while suppressing it in July and August by reducing intensity. Spatial precipitation changes correlate with upper-tropospheric humidity, while inter-annual changes link to geopotential height and wind anomalies. This suggests that irrigation-induced surface cooling and moisturizing modulate atmospheric thermodynamic and dynamic structures, influencing convective precipitation unevenly across regions and time, leading to complex precipitation changes. These findings highlight the complexity of irrigation impacts and emphasize the need for improved land representation in climate models.</p>","PeriodicalId":19438,"journal":{"name":"npj Climate and Atmospheric Science","volume":"42 1","pages":""},"PeriodicalIF":9.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assimilating summer sea ice thickness enhances predictions of Arctic sea ice and surrounding atmosphere within two months","authors":"Anling Liu, Jing Yang, Qing Bao, Frederic Vitart, Jiping Liu, Xi Liang, Mengqian Lu, Seong-Joong Kim, Daoyi Gong, Zhongxiang Tian, Hongbo Liu","doi":"10.1038/s41612-025-01050-8","DOIUrl":"https://doi.org/10.1038/s41612-025-01050-8","url":null,"abstract":"<p>Subseasonal prediction of Arctic sea ice and associated atmospheric conditions during the melting season remains challenging due to limited understanding of sea ice initial conditions. This study integrates sea ice assimilation into the coupled model FGOALS-f2 using the localized error subspace transform ensemble Kalman filter, and conducts subseasonal predictions starting from August 1st over 2004–2023. Results show that simultaneous assimilation of sea ice concentration (SIC) and thickness (SIT) significantly improves sea ice predictions for up to two months, while assimilating SIC alone primarily benefits one-month lead predictions. SIT assimilation provides added predictive value for surface air temperature (SAT) forecasts beyond SIC assimilation alone, effectively extending the atmospheric influence of sea ice initial conditions to two months. This improvement in SAT predictions is primarily attributed to a more realistic representation of the surface energy budget. These findings highlight the pivotal role of summer SIT assimilation to enhance subseasonal predictions in the Arctic and challenge the conventional view that initial conditions affect only short-term forecasts. This study underscores the necessity for better representation of ice–atmosphere interactions in models and advocates for enhanced observational capabilities for summer SIT to improve subseasonal predictions in the Arctic and surrounding regions.</p>","PeriodicalId":19438,"journal":{"name":"npj Climate and Atmospheric Science","volume":"33 1","pages":""},"PeriodicalIF":9.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electron Structures in Titan's Induced Magnetosphere and Low-Frequency Wave Activity","authors":"Konstantin Kim,&nbsp;Niklas J. T. Edberg,&nbsp;Ronan Modolo,&nbsp;Michiko Morooka,&nbsp;R. J. Wilson,&nbsp;Andrew J. Coates,&nbsp;Anne Wellbrock,&nbsp;Jan-Erik Wahlund,&nbsp;Erik Vigren,&nbsp;Ali Sulaiman,&nbsp;Cesar Bertucci,&nbsp;Ravindra Desai,&nbsp;Leonardo Regoli","doi":"10.1029/2024JE008802","DOIUrl":"https://doi.org/10.1029/2024JE008802","url":null,"abstract":"<p>The interaction of Titan's ionosphere with Saturn's magnetosphere leads to a mix of perturbed electromagnetic fields and accelerated and thermalized plasma in the induced magnetosphere. The complexity of this region has been noted in previous studies. However, many local structures and processes have not been studied and addressed in detail before. In this case study, we examine the origin of quasi-periodic plasma structures in Titan's induced magnetosphere observed during the T36 flyby. We use data from the electron and ion spectrometers CAPS/ELS and IMS, the RPWS Langmuir probe and electric antenna, and the fluxgate magnetometer (MAG) to analyze plasma parameters, for example, density and temperature and magnetic field fluctuations, to characterize the processes involved. The observed plasma structures are quasi-periodic on a scale of about 20 s (or local ion gyroperiod) and possess acceleration signatures from a few eV up to 700 eV. A burst of low-frequency (around the ion-cyclotron and lower-hybrid frequency) and low-amplitude (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mi>B</mi>\u0000 <mrow>\u0000 <mi>b</mi>\u0000 <mi>g</mi>\u0000 </mrow>\u0000 </msub>\u0000 <mo>≈</mo>\u0000 <mn>7</mn>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${B}_{bg}approx 7$</annotation>\u0000 </semantics></math> nT, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mi>δ</mi>\u0000 <mi>B</mi>\u0000 <mo>/</mo>\u0000 <msub>\u0000 <mi>B</mi>\u0000 <mrow>\u0000 <mi>b</mi>\u0000 <mi>g</mi>\u0000 </mrow>\u0000 </msub>\u0000 <mo>≈</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $delta B/{B}_{bg}approx $</annotation>\u0000 </semantics></math> 0.14) waves are observed in the proximity of the plasma structures. We discuss possible mechanisms leading to the development of the observed plasma structures, for example, magnetohydrodynamics instabilities and the contribution of the local electric fields.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008802","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual effects of climate change and socioeconomic development on flood exposure in the Yellow River Basin, China","authors":"Yixin Sun ,&nbsp;Qiang Zhang ,&nbsp;Gang Wang ,&nbsp;Chong-Yu Xu ,&nbsp;Vijay P. Singh ,&nbsp;Da Liu ,&nbsp;Kaiwen Zhang ,&nbsp;Anlan Feng ,&nbsp;Hushuang Ma","doi":"10.1016/j.ejrh.2025.102504","DOIUrl":"10.1016/j.ejrh.2025.102504","url":null,"abstract":"<div><h3>Study region</h3><div>The Yellow River Basin (YRB) in China.</div></div><div><h3>Study focus</h3><div>This research constructs and evaluates future flood-inundated urban land, population exposure, and GDP exposure in the YRB under various SSP-RCP scenarios. It also discusses the contributions of different factors to changes in exposure and quantifies the future flood control efficiency of flood protection measures.</div></div><div><h3>New hydrological insights for the region</h3><div>We find that provinces in the lower YRB have a higher proportion of flood-inundated urban land. By the end of the 21st century, the proportion of flood-inundated urban land of the cities in lower YRB is expected to increase. Meanwhile, the average population exposure in the YRB under different SSP scenarios will decrease by 6.22–47.23 %, while GDP exposure will increase by 68–72 % across all SSP scenarios. Compared to climate change, socio-economic development is the primary factor influencing flood exposure. Considering flood protection measures, the lower YRB exhibit higher flood control efficiency, while middle and upper YRB still face high exposure due to insufficient effectiveness of protection measures. Protective efficiency of existing flood control measures will further decline with climate change: by the end of the 21st century, only 25 % of cities in the YRB will effectively reduce population exposure, and 35 % will mitigate GDP exposure.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"60 ","pages":"Article 102504"},"PeriodicalIF":4.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimized spectral indices for camouflage detection in multispectral imagery","authors":"Tobias Hupel, Peter Stütz","doi":"10.1080/15481603.2025.2508574","DOIUrl":"https://doi.org/10.1080/15481603.2025.2508574","url":null,"abstract":"","PeriodicalId":55091,"journal":{"name":"GIScience & Remote Sensing","volume":"168 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}