AGU Advances最新文献

{"title":"Adjustments to Climate Perturbations—Mechanisms, Implications, Observational Constraints","authors":"Johannes Quaas,&nbsp;Timothy Andrews,&nbsp;Nicolas Bellouin,&nbsp;Karoline Block,&nbsp;Olivier Boucher,&nbsp;Paulo Ceppi,&nbsp;Guy Dagan,&nbsp;Sabine Doktorowski,&nbsp;Hannah Marie Eichholz,&nbsp;Piers Forster,&nbsp;Tom Goren,&nbsp;Edward Gryspeerdt,&nbsp;Øivind Hodnebrog,&nbsp;Hailing Jia,&nbsp;Ryan Kramer,&nbsp;Charlotte Lange,&nbsp;Amanda C. Maycock,&nbsp;Johannes Mülmenstädt,&nbsp;Gunnar Myhre,&nbsp;Fiona M. O’Connor,&nbsp;Robert Pincus,&nbsp;Bjørn Hallvard Samset,&nbsp;Fabian Senf,&nbsp;Keith P. Shine,&nbsp;Chris Smith,&nbsp;Camilla Weum Stjern,&nbsp;Toshihiko Takemura,&nbsp;Velle Toll,&nbsp;Casey J. Wall","doi":"10.1029/2023AV001144","DOIUrl":"https://doi.org/10.1029/2023AV001144","url":null,"abstract":"<p>Since the 5th Assessment Report of the Intergovernmental Panel on Climate Change (AR5) an extended concept of the energetic analysis of climate change including forcings, feedbacks and adjustment processes has become widely adopted. Adjustments are defined as processes that occur in response to the introduction of a climate forcing agent, but that are independent of global-mean surface temperature changes. Most considered are the adjustments that impact the Earth energy budget and strengthen or weaken the instantaneous radiative forcing due to the forcing agent. Some adjustment mechanisms also impact other aspects of climate not related to the Earth radiation budget. Since AR5 and a following description by Sherwood et al. (2015, https://doi.org/10.1175/bams-d-13-00167.1), much research on adjustments has been performed and is reviewed here. We classify the adjustment mechanisms into six main categories, and discuss methods of quantifying these adjustments in terms of their potentials, shortcomings and practicality. We furthermore describe aspects of adjustments that act beyond the energetic framework, and we propose new ideas to observe adjustments or to make use of observations to constrain their representation in models. Altogether, the problem of adjustments is now on a robust scientific footing, and better quantification and observational constraint is possible. This allows for improvements in understanding and quantifying climate change.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001144","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zircon Xenocrysts From Easter Island (Rapa Nui) Reveal Hotspot Activity Since the Middle Jurassic","authors":"Yamirka Rojas-Agramonte,&nbsp;Natalia Pardo,&nbsp;Douwe J. J. van Hinsbergen,&nbsp;Christian Winter,&nbsp;María Paula Marroquín-Gómez,&nbsp;Shoujie Liu,&nbsp;Axel Gerdes,&nbsp;Richard Albert,&nbsp;Shitou Wu,&nbsp;Antonio García-Casco","doi":"10.1029/2024AV001351","DOIUrl":"https://doi.org/10.1029/2024AV001351","url":null,"abstract":"<p>We report the finding of mantle-derived zircon grains retrieved from red soils, regoliths, and beach sands from Easter Island, that are much older than the island volcanism (0–2.5 Ma) and its underlying lithosphere (Pliocene, 3–4.8 Ma). A large population of 0–165 Ma old zircons have coherent oxygen (δ¹⁸O 3.8–5.9‰) and hafnium (εHf_(t)+3.5–+12.5) mantle isotopic signatures. These results are consistent with the crystallization of zircon from plume-related melts. In addition, a chemically diverse population with ages from the Paleozoic to the Archean was found. These older populations are enigmatic but they could represent remnants of ancient subducted sediments. Meanwhile, the ∼0–165 Ma population is interpreted as plume-derived, suggesting that the hotspot started at least ∼165 Ma ago. A spike of ∼164–160 Ma zircons could represent a Large Igneous Province (LIP) stage upon the first arrival of the plume. We use plate reconstructions to show that such a LIP would have formed on the Phoenix Plate and would have subducted below the Antarctic Peninsula around 100–105 Ma. There, LIP subduction would offer a solution for the enigmatic Palmer Land deformation event, previously proposed to result from a collision with an unknown indenter. The here-reported “ghost” of a prolonged hotspot activity suggests that fragments of the Easter plume and of the ambient sub-lithospheric mantle stored and re-sampled zircon xenocrysts due to convective (re)circulation at the scale of the plume head. Our study demonstrates how zircon geochronology and geochemistry provide novel insights into global-scale geodynamics, offering new perspectives on the dynamics of mantle plumes and hotspot activity.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001351","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plume-Plateau Interaction","authors":"Shichun Huang","doi":"10.1029/2024AV001464","DOIUrl":"https://doi.org/10.1029/2024AV001464","url":null,"abstract":"&lt;p&gt;Age progressive volcanic trends, known as hotspot tracks, are thought to be produced by partial melting of buoyant mantle plumes rising from the deep mantle (Morgan, &lt;span&gt;1971&lt;/span&gt;; Wilson, &lt;span&gt;1963&lt;/span&gt;). Hotspot tracks record the relative motion between plates and mantle plumes, and they are used to reconstruct the history of plate motion and to constrain the geochemical heterogeneity within the mantle, which are important to our understanding of mantle dynamics (e.g., Koppers et al., &lt;span&gt;2021&lt;/span&gt;; Weis et al., &lt;span&gt;2023&lt;/span&gt;).&lt;/p&gt;&lt;p&gt;Through a careful examination of isotopic, geochronological, and plate motion reconstruction data, Jackson et al. (&lt;span&gt;2024&lt;/span&gt;) argued that certain Cretaceous (87–106 Ma) Magellan seamounts north of the Ontong-Java Plateau (OJP) may have been produced by the Samoan plume. This finding places the Samoan hotspot track among the longest-lived ones. However, there is a significant gap in volcanic activity from 24 to 87 Ma, excluding the 44 Ma Malaita volcanism. Raising the question, what mechanism could produce a 63 Ma gap in an otherwise enduring hotspot track?&lt;/p&gt;&lt;p&gt;It has long been observed that most hotspot tracks manifest as discrete volcanoes, exemplified by the long-lived Hawaii-Emperor Volcanic Chain, rather than continuous ridges. It is suggested that the locations of these volcanoes are controlled by fractures within the lithosphere, facilitating the migration of plume-generated magma (e.g., Hieronymus &amp; Bercovici, &lt;span&gt;1999&lt;/span&gt;). Consequently, discrete volcanoes are anticipated along hotspot tracks.&lt;/p&gt;&lt;p&gt;To explain the bilaterally zoned hotspot tracks (e.g., Abouchami et al., &lt;span&gt;2005&lt;/span&gt;; Huang et al., &lt;span&gt;2011&lt;/span&gt;; Weis et al., &lt;span&gt;2011&lt;/span&gt;), Rohde et al. (&lt;span&gt;2013&lt;/span&gt;) argued that mantle plumes originating from the lower mantle may bifurcate at the mantle transition zone (Figure 1a). Because of the different mantle viscosities in the upper and lower mantle, a plume might rise much slower in the lower mantle compared to in the upper mantle. To maintain the same plume flux, a plume would become thinner in the upper mantle, which may lead to plume bifurcation at the mantle transition zone (Rohde et al., &lt;span&gt;2013&lt;/span&gt;). Alternatively, it is also possible that after entering the upper mantle, a plume fragments into discrete upwelling diapirs rather than maintaining a continuous flow (Figure 1a), resulting in volcanic activity gaps along hotspot tracks.&lt;/p&gt;&lt;p&gt;However, neither of these theories explains the prolonged absence of volcanism within a significant period (24–87 Ma) of the Samoan hotspot track. Jackson et al. (&lt;span&gt;2024&lt;/span&gt;) noted that during this particular period of time, the Samoan plume was under the thick OJP. Mantle plumes ascend adiabatically, with a steeper pressure-temperature slope compared to that of the mantle solidus. As such, plumes start to melt and produce magma when reaching shallow depths (low pressure). The upwelling stops ","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001464","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetosheath High-Speed Jet Drives Multiple Auroral Arcs Near Local Noon","authors":"Hui-Xuan Qiu,&nbsp;De-Sheng Han,&nbsp;Run Shi,&nbsp;Jianjun Liu","doi":"10.1029/2024AV001197","DOIUrl":"https://doi.org/10.1029/2024AV001197","url":null,"abstract":"<p>Magnetosheath High-Speed Jets (HSJs) are transient disturbances characterized by increased dynamic pressure. They can cause various geoeffects, including ultra-low-frequency (ULF) waves and auroras. Theoretically, when ULF waves propagate into the ionosphere as Alfvén waves, they can accelerate electrons and generate discrete auroras. However, what types of aurora can be driven by HSJs and what are the underlying mechanisms remain unknown. Using coordinated magnetosheath in situ and ground observations, here, we showed that when a HSJ was identified in the magnetosheath, multiple auroral arcs parallel to the auroral oval were observed near local noon. The electron energy spectrogram of these arcs exhibited “inverted-V” structures, indicating the existence of quasi-static parallel electric fields. Concurrently, long-period ULF signals were detected on the ground, suggesting the arrival of Alfvén waves. These observations are represented by a kinetic simulation using realistic observational inputs, showing consistency with the theory regarding the generation of the “inverted-V” structure by long-period Alfvén waves. This study builds a previously unestablished connection among HSJ, ULF wave, and aurora, and provides a mechanism for generation of discrete auroral arcs near local noon, which may reveal the underlying mechanism behind a specific auroral activity commonly observed near local noon as shown in the paper.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001197","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large, Negative Atmospheric Carbon Monoxide Clumped Isotope Values Result From Kinetic Isotope Fractionation, Tracing OH• Reactivity","authors":"Gregory A. Henkes,&nbsp;Philip F. Place,&nbsp;John E. Mak","doi":"10.1029/2023AV000922","DOIUrl":"https://doi.org/10.1029/2023AV000922","url":null,"abstract":"<p>Because of its global abundance and reactivity with hydroxyl radicals (OH•), tropospheric carbon monoxide indirectly impacts the lifetimes of other OH•-reactive gases, in particular methane and reactive hydrocarbons. The origin and chemistry of atmospheric CO have been studied using stable isotopes. Both ¹³CO and C¹⁸O undergo isotopic fractionation during its main chemical loss reaction, CO + OH•. The kinetic isotope effect (KIE) for ¹³CO is mass dependent, with a value of ∼5‰; ¹²CO reacts faster than ¹³CO with OH. Whereas C¹⁸O + OH• exhibits an inversely mass dependent KIE ∼−10‰. We hypothesize these KIEs result in a relative depletion of ¹³C¹⁸O, a CO clumped isotope. To test this, we collected CO from air samples on Long Island, NY, and discovered a −3 to −8‰ difference in the clumped isotope ratio, Δ₃₁, relative to a random distribution of ¹³C and ¹⁸O in CO. A clear negative trend between [CO] and Δ₃₁ is driven by two factors: (a) the atmospheric addition of CO from either a primary or secondary source with a Δ₃₁ of ∼0‰ and (b) the continuing reaction of CO with OH•, leaving the remaining CO pool relatively depleted in ¹³C¹⁸O. This is analogous to the mechanism that determines CO Δ¹⁷O values. This study is among the first to show clumped isotope fractionation resulting from atmospheric chemistry and not thermal equilibration, which may inform the identification of clumped isotope KIEs in other atmospheric trace gases. These first Δ₃₁ observations motivate future experimental and observational studies targeted at characterizing the clumped isotopes of CO sources, background CO, and experimentally fractionated CO.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV000922","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Low-Viscosity Lower Lunar Mantle Implied by Measured Monthly and Yearly Tides","authors":"Sander Goossens,&nbsp;Isamu Matsuyama,&nbsp;Gael Cascioli,&nbsp;Erwan Mazarico","doi":"10.1029/2024AV001285","DOIUrl":"https://doi.org/10.1029/2024AV001285","url":null,"abstract":"<p>The Moon's frequency-dependent tidal response, expressed as temporal variations in its gravity field through the Love number <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>k</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${k}_{2}$</annotation>\u0000 </semantics></math> and as dissipation through the quality factor <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Q</mi>\u0000 </mrow>\u0000 <annotation> $Q$</annotation>\u0000 </semantics></math>, provides information about its interior structure. Lunar laser ranging has provided measurements for <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Q</mi>\u0000 </mrow>\u0000 <annotation> $Q$</annotation>\u0000 </semantics></math>, but so far no frequency-dependent values for <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>k</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${k}_{2}$</annotation>\u0000 </semantics></math> have been determined. We provide the first spacecraft measurements of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>k</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${k}_{2}$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Q</mi>\u0000 </mrow>\u0000 <annotation> $Q$</annotation>\u0000 </semantics></math> at two frequencies, monthly and yearly, from an analysis of Gravity Recovery and Interior Laboratory and Lunar Reconnaissance Orbiter radio tracking data. Interior modeling indicates that these values can be matched only with a low-viscosity zone at the base of the lunar mantle, even when using complex rheological laws to model the mantle's response. The existence of this zone has profound implications for the Moon's thermal state and evolution.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001285","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142233190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topographic Roughness as an Emergent Property of Geomorphic Processes and Events","authors":"T. H. Doane,&nbsp;J. H. Gearon,&nbsp;H. K. Martin,&nbsp;B. J. Yanites,&nbsp;D. A. Edmonds","doi":"10.1029/2024AV001264","DOIUrl":"https://doi.org/10.1029/2024AV001264","url":null,"abstract":"<p>Earth's terrestrial surfaces commonly exhibit topographic roughness at the scale of meters to tens of meters. In soil- and sediment-mantled settings topographic roughness may be framed as a competition between roughening and smoothing processes. In many cases, roughening processes may be specific eco-hydro-geomorphic events like shrub deaths, tree uprooting, river avulsions, or impact craters. The smoothing processes are all geomorphic processes that operate at smaller scales and tend to drive a diffusive evolution of the surface. In this article, we present a generalized theory that explains topographic roughness as an emergent property of geomorphic systems (semi-arid plains, forests, alluvial fans, heavily bombarded surfaces) that are periodically shocked by an addition of roughness which subsequently decays due to the action of all small scale, creep-like processes. We demonstrate theory for the examples listed above, but also illustrate that there is a continuum of topographic forms that the roughening process may take on so that the theory is broadly applicable. Furthermore, we demonstrate how our theory applies to any geomorphic feature that can be described as a pit or mound, pit-mound couplet, or mound-pit-mound complex.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001264","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parsimonious High-Resolution Landslide Susceptibility Modeling at Continental Scales","authors":"Benjamin B. Mirus,&nbsp;Gina M. Belair,&nbsp;Nathan J. Wood,&nbsp;Jeanne Jones,&nbsp;Sabrina N. Martinez","doi":"10.1029/2024AV001214","DOIUrl":"https://doi.org/10.1029/2024AV001214","url":null,"abstract":"<p>Landslide susceptibility maps are fundamental tools for risk reduction, but the coarse resolution of current continental-scale models is insufficient for local application. Complex relations between topographic and environmental attributes characterizing landslide susceptibility at local scales are not transferrable across areas without landslide data. Existing maps with multiple susceptibility classifications under-represent landslide potential in moderate and gently sloping terrain. We leverage an extensive landslide database (<i>N</i> = 613,724), a high-resolution digital elevation model (10-m), and high-performance computing resources, to develop a new nationwide susceptibility map for the contiguous United States, Hawaii, Alaska, and Puerto Rico. We calculate four alternative linear and nonlinear thresholds of topographic slope and relief using an objective split-sample calibration. We down-sample our results to a 90-m grid to account for uncertainty in the digital elevation model and landslide position, and evaluate these thresholds' ability to differentiate areas of greater susceptibility. The less conservative nonlinear model optimally balances our priorities of capturing observed landslides (99%) while minimizing area covered by susceptible terrain (43%). Independent evaluation with four statewide landslide inventories (<i>N</i> = 172,367) reinforces our model selection but highlights spatially variable performance. Therefore, we propose a novel approach to susceptibility classification using the concentration of landslide-prone terrain within each down-sampled grid. While landslides are possible within any cells containing susceptible terrain, those with the highest concentration capture the majority of observed landslides. Our new map characterizes landside susceptibility more consistently than prior models; our transparent classification approach also provides flexibility for accommodating different tolerances in risk reduction measures.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001214","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142170219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boreal Forest Fire Causes Daytime Surface Warming During Summer to Exceed Surface Cooling During Winter in North America","authors":"M. Helbig,&nbsp;L. Daw,&nbsp;H. Iwata,&nbsp;L. Rudaitis,&nbsp;M. Ueyama,&nbsp;T. Živković","doi":"10.1029/2024AV001327","DOIUrl":"https://doi.org/10.1029/2024AV001327","url":null,"abstract":"<p>Boreal wildfires modify surface climates affecting plant physiology, permafrost thaw, and carbon fluxes. Post-fire temperatures vary over decades because of successional vegetation changes. Yet, the underlying biophysical drivers remain uncertain. Here, we quantify surface climate changes following fire disturbances in the North American boreal forest and identify its dominant biophysical drivers. We analyze multi-year land-atmosphere energy exchange and satellite observations from across North America and find post-fire daytime surface temperatures to be substantially warmer for about five decades while winter temperatures are slightly cooler. Post-fire decadal changes are characterized by decreasing leaf area index during the first decade, by sharply increasing surface albedo during the snow cover period, and by a less efficient heat exchange between the forest and the atmosphere caused by decreasing surface roughness for about 2–3 decades. Over the first three decades, the amount of energy used for evapotranspiration increases before returning to lower values. We find that surface warming is mainly explained by less efficient forest-atmosphere heat exchange while cooling is additionally explained by increasing surface albedo. We estimate that biome-wide daytime surface temperatures of the Canadian boreal forest in 2024 are 0.27°C warmer in the summer and 0.02°C cooler during the winter because of fire. For a scenario with a strong increase in burned area, we estimate annual warming from fire to increase by a third until 2050. Our study highlights the potential for accelerated surface warming in the boreal biome with increasing wildfire activity and disentangles the biophysical drivers of fire-related surface climate impacts.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001327","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142137742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strong Effects of Chorus Waves on Radiation Belts Expected for Future Magnetic Superstorms","authors":"Ondřej Santolík,&nbsp;Yuri Shprits,&nbsp;Ivana Kolmašová,&nbsp;Dedong Wang,&nbsp;Ulrich Taubenschuss,&nbsp;Marie Turčičová,&nbsp;Miroslav Hanzelka","doi":"10.1029/2024AV001234","DOIUrl":"https://doi.org/10.1029/2024AV001234","url":null,"abstract":"<p>Processes in the radiation belts under extreme geomagnetic conditions involve the interplay between acceleration and loss processes, both of which can be caused by wave-particle interactions. Whistler mode waves play a critical role in these interactions, and up to now their properties during extreme events remained poorly sampled and understood. We employ extensive databases of spacecraft observations to specify their distribution. We show that under extreme geomagnetic conditions, lower-band whistler mode chorus waves have a net effect of accelerating ultra-relativistic electrons, which results in an increase of fluxes at multi-MeV energies by several orders of magnitude. During future magnetic superstorms, the radiation levels in the outer zone could therefore experience a substantial increase beyond what has been previously observed during the space age.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001234","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142137741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}