{"title":"A Marine Barite Perspective of the Late Miocene Biogenic Bloom in the Equatorial Indian Ocean and Equatorial Western Atlantic Ocean","authors":"Xinying Wu, Yue Hu, Jingbo Nan, Weiqi Yao","doi":"10.1029/2024GL111748","DOIUrl":"https://doi.org/10.1029/2024GL111748","url":null,"abstract":"<p>The marine biological pump is crucial for removing excess carbon dioxide from the atmosphere to the ocean interior and seafloor sediments. The Late Miocene Biogenic Bloom (LMBB), marked by notable increases in biogenic components in marine sediments, provides insights into the response of the biological pump to climate change. However, understanding the timing, distribution, and cause of the LMBB remains limited. We use marine barite, a refractory mineral precipitating from the water column associated with carbon export, and other proxies to reconstruct productivity in the equatorial Indian Ocean and equatorial western Atlantic between 12 and 5 Ma. Multi-proxy records reveal the onset of the LMBB in the equatorial Indian Ocean at ∼9 Ma, primarily driven by more vigorous upwelling during global cooling. We suggest that the steepened meridional temperature gradient and the Antarctic ice sheet expansion have strengthened ocean overturning, facilitating nutrient supply and biogenic bloom in upwelling regions.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111748","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142666123","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":"Enhanced Ocean Mixing During the Passage of Tropical Cyclone","authors":"Devang Falor, Bishakhdatta Gayen, Debasis Sengupta, Dipanjan Chaudhuri","doi":"10.1029/2024GL111925","DOIUrl":"10.1029/2024GL111925","url":null,"abstract":"<p>Tropical cyclones are among the most destructive natural disasters. However, lack of detailed observations and the simplifications inherent in operational ocean models, lead to incomplete knowledge of underlying ocean processes. Using high-fidelity large-eddy simulations and moored observations away from the storm track, we show that mutually interacting shear and convective processes, govern the evolving state of the upper ocean. Our simulation agrees well with observed sea surface temperature and sea surface salinity. Shear driven turbulence due to surface wind stress erodes stratification, deepens the ocean mixed layer and transports freshwater into the mixed layer during rain events. Concurrently, surface buoyancy loss also aids in ocean mixing via convective entrainment. The mixing efficiency and the associated eddy diffusivity shows high spatiotemporal variability throughout the water column during cyclone passage. Thus, a better insight into the upper ocean mixing mechanisms is necessary for developing improved mixing parameterizations for tropical cyclone intensity forecasts.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111925","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142672931","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":"Unexpected Warming From Land Radiative Management","authors":"Yu Cheng, Kaighin A. McColl","doi":"10.1029/2024GL112433","DOIUrl":"10.1029/2024GL112433","url":null,"abstract":"<p>“Land radiative management” (LRM)—deliberately increasing surface albedo to decrease temperatures—has been proposed as a form of geoengineering to mitigate the effects of regional warming. Here, we show that, contrary to expectations, LRM causes temperatures to increase in surrounding regions. The basic reason for the increase is unintended impacts on precipitation. Precipitation is suppressed over the LRM region, but this effect also extends to nearby areas unprotected by LRM. The reduction in precipitation and soil moisture in these regions leads to higher temperatures than would be expected in the absence of LRM. The resulting warming outside the LRM region is comparable to the cooling achieved inside it. This implies that, if wealthy regions unilaterally adopt LRM to cool, their neighbors may experience warming, worsening heat inequality.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL112433","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142672933","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}
Ebony L. Williams, Christopher B. Kratt, Raymond S. Rodolfo, Mark R. Lapus, Ryan R. Lardizabal, Aya S. Bangun, Amber T. Nguyen, Scott W. Tyler, M. Bayani Cardenas
{"title":"Multi-Scale Thermal Mapping of Submarine Groundwater Discharge in Coastal Ecosystems of a Volcanic Area","authors":"Ebony L. Williams, Christopher B. Kratt, Raymond S. Rodolfo, Mark R. Lapus, Ryan R. Lardizabal, Aya S. Bangun, Amber T. Nguyen, Scott W. Tyler, M. Bayani Cardenas","doi":"10.1029/2024GL111857","DOIUrl":"https://doi.org/10.1029/2024GL111857","url":null,"abstract":"<p>Submarine groundwater discharge (SGD) in volcanic areas commonly exhibits high temperatures, concentrations of metals and CO<sub>2</sub>, and acidity, all of which could affect sensitive coastal ecosystems. Identifying and quantifying volcanic SGD is crucial yet challenging because the SGD might be both discrete, through fractured volcanic rock, and diffuse. At a volcanic area in the Philippines, the novel combination of satellite and drone-based thermal infrared remote sensing, ground-based fiber-optic distributed temperature sensing, and in situ thermal profiling in coastal sediment identified the multi-scale nature of SGD and quantified fluxes. We identified SGD across ∼30 km of coastline. The different approaches revealed numerous SGD signals from the intertidal zone to about a hundred meters offshore. In active seepage areas, temperatures peaked at 80°C, and Darcy fluxes were as high as 150 cm/d. SGD is therefore locally prominent and regionally important across the study area.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111857","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142666131","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}
James W. Head, Xing Wang, Laura H. Lark, Lionel Wilson, Yuqi Qian
{"title":"Lunar Nearside-Farside Mare Basalt Asymmetry: The Combined Role of Global Crustal Thickness Variations and South Pole-Aitken (SPA) Basin-Induced Lithospheric Thickening","authors":"James W. Head, Xing Wang, Laura H. Lark, Lionel Wilson, Yuqi Qian","doi":"10.1029/2024GL110510","DOIUrl":"10.1029/2024GL110510","url":null,"abstract":"<p>Lunar mare basalts represent melting of mantle material, buoyant ascent in dikes, and eruption onto <20% of the surface. Global mare distribution is distinctly asymmetrical, with a paucity on the farside, plausibly interpreted to be related to thicker farside low-density crust inhibiting buoyant magma rise to the surface. Challenging this hypothesis is the presence of the huge, ancient farside South Pole-Aitken (SPA) basin, site of the thinnest crust and deepest depression observed on the Moon. We hypothesize that an oblique impact stripped the farside crust within the SPA basin, permitting early mare basalt emplacement as cryptomaria due to thin/absent crust. However, removal of the SPA thermally insulating megaregolith/crust accelerated lithosphere thickening beneath the basin. This deepening rheological barrier inhibited buoyant rise of mantle diapirs below SPA, resulting in early abatement of mare basalt extrusions compared to the nearside, and retention of the deep, underfilled SPA impact basin observed today.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL110510","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665333","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}
P. De Luca, B. Jiménez-Esteve, L. Degenhardt, S. Schemm, S. Pfahl
{"title":"Enhanced Blocking Frequencies in Very-High Resolution Idealized Climate Model Simulations","authors":"P. De Luca, B. Jiménez-Esteve, L. Degenhardt, S. Schemm, S. Pfahl","doi":"10.1029/2024GL111016","DOIUrl":"https://doi.org/10.1029/2024GL111016","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <p>Atmospheric blocking is a key dynamical phenomenon in the mid- and high latitudes, able to drive day-to-day weather changes and meteorological extremes such as heatwaves, droughts and cold waves. Current global circulation models struggle to fully capture observed blocking frequencies, likely because of their coarse horizontal resolution. Here we use convection permitting, nested idealized model simulations for quantifying changes in blocking frequency and Rossby wave breaking compared to a coarser resolution reference. We find an increase in blocking frequency poleward and downstream of the area with increased resolution, while the exact regions depend on the blocking index. These changes are probably due to a more accurate representation of small-scale processes such as diabatic heating, which affect Rossby wave breaking and blocking formation downstream. Our results thus suggest an improved representation of blocking in the next generation of high-resolution global climate models.</p>\u0000 </section>\u0000 </div>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142666063","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}
Q. Ma, W. Li, X.-J. Zhang, N. Kang, J. Bortnik, M. Qin, X.-C. Shen, C. J. Meyer-Reed, A. V. Artemyev, W. S. Kurth, G. B. Hospodarsky, J. D. Menietti, S. J. Bolton
{"title":"Survey of Whistler-Mode Wave Amplitudes and Frequency Spectra in Jupiter's Magnetosphere","authors":"Q. Ma, W. Li, X.-J. Zhang, N. Kang, J. Bortnik, M. Qin, X.-C. Shen, C. J. Meyer-Reed, A. V. Artemyev, W. S. Kurth, G. B. Hospodarsky, J. D. Menietti, S. J. Bolton","doi":"10.1029/2024GL111882","DOIUrl":"10.1029/2024GL111882","url":null,"abstract":"<p>We present statistical distributions of whistler-mode chorus and hiss waves at frequencies ranging from the local proton gyrofrequency to the equatorial electron gyrofrequency (<i>f</i><sub><i>ce,eq</i></sub>) in Jupiter's magnetosphere based on Juno measurements. The chorus wave power spectral densities usually follow the <i>f</i><sub><i>ce,eq</i></sub> variation with major wave power concentrated in the 0.05<i>f</i><sub><i>ce,eq</i></sub>–<i>f</i><sub><i>ce,eq</i></sub> frequency range. The hiss wave frequencies are less dependent on <i>f</i><sub><i>ce,eq</i></sub> variation than chorus with major power concentrated below 0.05<i>f</i><sub><i>ce,eq</i></sub>, showing a separation from chorus at <i>M</i> < 10. Our survey indicates that chorus waves are mainly observed at 5.5 < <i>M</i> < 13 from the magnetic equator to 20° latitude, consistent with local wave generation near the equator and damping effects. The hiss wave powers extend to 50° latitude, suggesting longer wave propagation paths without attenuation. Our survey also includes the whistler-mode waves at high latitudes which may originate from the Io footprint, auroral hiss, or propagating hiss waves reflected to high <i>M</i> shells.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111882","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665334","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":"A Critical Core Size for Dynamo Action at the Galilean Satellites","authors":"K. T. Trinh, C. J. Bierson, J. G. O’Rourke","doi":"10.1029/2024GL110680","DOIUrl":"10.1029/2024GL110680","url":null,"abstract":"<p>Ganymede is the only known moon with an active dynamo. No mission has discovered intrinsic magnetism at the other Galilean satellites: Io, Europa, and Callisto. A dynamo requires a large magnetic Reynolds number, which in turn demands, for these moons, a large metallic core that is cooling fast enough for convection. Here we quantify these requirements to construct a regime diagram for the Galilean satellites. We compute the internal heat fluxes that would sustain a dynamo over the wide ranges of plausible radii for their metallic cores. Below a critical radius, no plausible heat flux will sustain a dynamo. Europa likely sits on the opposite side of this limit than Ganymede and Io. We predict that future missions may confirm a small (or absent) core, meaning that Europa could not sustain a dynamo even if its interior were cooling as quickly as Ganymede's core.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL110680","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665374","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}
Dillon J. Amaya, Michael G. Jacox, Michael A. Alexander, Steven J. Bograd, Liwei Jia
{"title":"Seasonal Upwelling Forecasts in the California Current System","authors":"Dillon J. Amaya, Michael G. Jacox, Michael A. Alexander, Steven J. Bograd, Liwei Jia","doi":"10.1029/2024GL111083","DOIUrl":"10.1029/2024GL111083","url":null,"abstract":"<p>Coastal upwelling plays a vital role in the support and maintenance of productive marine ecosystems throughout the California Current System (CCS). Here, we evaluate upwelling forecast skill using ∼30 years of seasonal reforecasts from four global climate models contributing to the North American Mulitmodel Ensemble (NMME). The models skillfully predict upwelling intensity throughout much of the CCS in boreal winter, and in the South-Central CCS in spring/summer. The models also skillfully predict various aspects of upwelling phenology, including the timing of the spring transition, as well as the total vertical transport integrated over the course of the upwelling season. Climatic sources of forecast skill vary with season, with contributions from the El Niño-Southern Oscillation in winter-spring, and the North Pacific Oscillation and the North Pacific Meridional Mode in the winter-summer. Our results highlight the potential of seasonal climate forecasts to inform management of upwelling-sensitive marine resources.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665371","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}
Kuan-Chieh Chen, Chi-Cherng Hong, Chi-Chun Chang, Jun Chiang, Sheng-Hsiang Chang
{"title":"Possible Causes for the Unprecedented Low/High Tropical Cyclone Activities in the Northern Pacific/Atlantic in 2023 El Niño","authors":"Kuan-Chieh Chen, Chi-Cherng Hong, Chi-Chun Chang, Jun Chiang, Sheng-Hsiang Chang","doi":"10.1029/2024GL111964","DOIUrl":"10.1029/2024GL111964","url":null,"abstract":"<p>This study reported the unprecedented tropical cyclone (TC) activity in the western North Pacific (WNP) and North Atlantic (NA) during the developing year of the 2023/2024 El Niño. The possible causes behind these unusual features were addressed. In contrast to previous El Niño events, an unusual low/high TC genesis number in the WNP/NA was identified during the typhoon season (June–November) in 2023. Meanwhile, the mean TC genesis location in the WNP exhibited a La Niña-like northwestward shift, rarely observed in an El Niño developing year. An observational diagnosis on TC-genesis-related large-scale dynamics and thermodynamics revealed that the lower/higher TC numbers in the WNP/NA were primarily attributed to an anticyclonic/cyclonic anomaly linked to trans-basin sea surface temperature anomalies in the tropics and extratropics. Additionally, weaker intraseasonal oscillation activity compared to previous El Niños also partially contributed to fewer TCs in the WNP.</p>","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"51 22","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GL111964","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645893","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}