Abstract Canada experienced an unprecedented wildfire season in 2023. Here, we analyzed the exceptional scale, dominant driving factors, and potential impacts on permafrost of these wildfires using Moderate Resolution Imaging Spectroradiometer burned area (BA) observations and machine learning methods. We found that the 2023 coast‐to‐coast wildfires raged a staggering area of 13.02 Mha, more than seven times the historical average (2001–2022). The extreme wildfires were predominantly driven by record‐breaking drought, characterized by heightened atmospheric aridity and reduced precipitation, with specific water deficit thresholds triggering sharp increases in BA. Over 80% of the 2023 wildfires occurred in Canada's permafrost regions, with burned areas increasing more than six‐fold across extensive permafrost, including Arctic regions. These wildfires are expected to accelerate permafrost degradation and considerable carbon release from thawing, presenting previously overlooked risks. Our results emphasize the urgent need for immediate climatic action to mitigate climate change and pressures from wildfire and permafrost degradation.
Hyperspectral image (HSI) has more spectral information than conventional images, which helps to distinguish targets in a complex scene more accurately. However, HSI typically has a low spatial resolution, which limits their application scenarios. To achieve high-resolution HSI, we propose a spectral and spatial multiscale coupling fusion model (SSMSFuse) for hyperspectral and multispectral image (MSI). SSMSFuse couples the spatial information of MSI and the spectral information of HSI at multiscales by means of a two-branch network structure, thus obtaining the fused images with high spatial and spectral resolution. SSMSFuse consists of two branches, namely the spatial embedding network (Spa-Net) and the spectral embedding network (Spe-Net). Spa-Net is constructed using a multiscale convolutional neural network to better mine multilevel spatial features from MSI. Spe-Net is constructed using self-attention, which can model the long-distance spectral dependencies of HSI to better extract spectral information from HSI. Finally, to achieve interactive coupling of dual-branch information, we designed a spatial–spectral guidance fusion block to fuse features at different scales to avoid loss of spatial and spectral details. Experiments are carried out on four public datasets, and the results show that the proposed method can effectively improve the objective indicators of the fusion results, such as the peak signal to noise ratio, which is increased by 1.36%, and the root mean square error, which is increased by 9.72% on the CAVE dataset, and satisfactory subjective results are also obtained.
Abstract Following the highly impactful 2013–2016 Marine Heatwave (MHW), another MHW occurred in the Northeast Pacific during summer 2019. While the physical drivers of this event are well described, its biogeochemical impacts remain poorly understood. We use Ocetrac, a Python package that tracks spatiotemporal extreme events, to identify physical and biogeochemical anomalies associated with the 2019 MHW within two observation‐based products, GOBAI‐O2 and MOBO‐DIC, and model output from the Community Earth System Model Forced Ocean Sea Ice Reconstruction (FOSI). Our findings reveal that warm temperature anomalies associated with the MHW negatively correlate with dissolved inorganic carbon (DIC) and dissolved oxygen (DO). Model reconstruction suggests that DIC anomalies were driven by air‐sea flux and biological processes, while anomalies in DO are linked to air‐sea flux and circulation. These results underscore the utility of new observational products and models for assessing the biogeochemical consequences of MHWs.
Abstract The Nkhata basin located in the central part of the Malawi rift consists of Late Quaternary (Chibanian to present; <750 ka) sediments and are the youngest sediments within the great East African Rift System. Rock-Eval pyrolysis and Total Organic Carbon (TOC) analysis of 163 samples from cores GLAD7_MAL05_1B (56–390 m) and GLAD7_MAL05_1C (0–78 m), drilled in the western-central basin, integrated with X-ray Fluorescence (XRF) data are used to assess the source potential of these organic matter-rich sediments within Lake Malawi. Results reveal intervals of good to excellent organic matter-rich silty clay and carbonate mud (TOC > 6.02 wt% and S2 > 25.55 mg HC/g rock; 1 C: TOC up to 6.16 wt%, S2 up to 56.9 mg HC/g rock). The sediments were dominated by oil prone Type II and mixed Type II/II kerogens. Despite wide range TOC values (0.25–7.22 wt%) sandy silty clay facies show poor to good organic quantity and is dominated by Type III/IV kerogens. The overall thermal maturity index suggests immature to early oil window (Tmax: 327–444 °C; PI: 0.01–0.64) sediments. Redox proxies (V/Cr, V/(V + Ni), S/Fe) show deposition occurred under predominantly oxic-dysoxic bottom waters, with two discrete anoxic/euxinic events (1B: 186 m, 288–298 m). These events correlate with peak TOC values (6.02 wt% at 274.3 m), signifying that episodic euxinia significantly enhanced organic matter preservation by suppressing aerobic degradation. The Nkhata Basin exhibits compelling source rock characteristics comparable to other productive basins within the East African rift system but requires deeper burial to achieve generative maturity.
Owing to the rapid urbanization combined with global climate change, dramatic land-use change in coastal watersheds is occurred, which, in turn, cause the evolution of landscape patterns and threaten the valuable but fragile ecosystem. The coastal zone is characterized by severe cloud cover, frequent changes in land type, and fragmented landscape, so it is challenging to carry out the accurate landscape patterns analysis. To address this problem, this study employed the Google Earth engine cloud platform, Landsat time series, and landscape metrics in the Fragstats model to develop a comprehensive framework that integrates landscape pattern metrics and spatial analysis methods, considering both type level and landscape level. The Hangzhou Bay region was selected for conducting land-use classification and landscape patterns analysis. The results indicate that, during nearly four decades, with the continuous expansion of the urban, the urbanization process has accelerated, and the construction land has expanded by 6.93 times. By analyzing the evolution of landscape patterns, Hangzhou Bay heightened landscape fragmentation and patch shapes became more irregular caused by a trend toward intensified urbanization. The Shannon's diversity index continuously increased from 1.14 to 1.51, while the contagion index consistently decreased from 59.83% to 42.21%, suggesting an increase in land-use diversity, reduced aggregation, and extension tendencies between land patches, along with a decrease in the proportion of highly connected patches within the landscape. This study is anticipated to provide robust evidence for the rational planning of future development directions and the deployment of landscape ecological spatial services.
Abstract Knowledge regarding the abundance and distribution of solar wind (SW)‐sourced water (OH/H2O) on the Moon in the shallow subsurface remains limited. Here, we report the NanoSIMS measurements of H abundances and D/H ratios on soil grains from three deepest sections of the Chang'E‐5 drill core sampled at depths of 0.45–0.8 m. High water contents of 0.13–1.3 wt.% are present on approximately half of the grain surfaces (topmost ∼100 nm), comparable to the values of Chang'E‐5 scooped soils. The extremely low δD values (as low as −995‰) and negative correlations between δD and water contents indicate that SW implantation is an important source of water beneath the lunar surface. The results are indicative of homogeneous distribution of SW‐derived water in the vertical direction, providing compelling evidence for the well‐mixed nature of the lunar regolith. Moreover, the findings demonstrate that the shallow subsurface regolith of the Moon contains a considerable amount of water.
Abstract The stress paths of the cylindrical specimen in the p–q stress space by controlling the ratio of the axial and the radial loading is guaranteed to be consistent with the cuboid specimen, a novel method for imitating true-triaxial stress path by conventional triaxial apparatus was presented. Under the condition that p and q were variables and b was constant, the true-triaxial stress paths were realized by conventional triaxial apparatus strictly and easily. Under the condition that b and p were invariants, the b was used to control the ratio of axial and radial loading to ensure p constant, the method can be used to measure the strength on the π plane. If the tests were conducted at the different p with the same b, the critical state line of different b could be obtained. Under the condition that p and q were constant, the proposed method of nonlinear loading with b as a parameter could be used to design the various stress paths of true-triaxial under the condition of deviatoric stress consolidation, and which could be used to determine the deformation and the plastic flow of soil in 3D space. The proposed method could be used to achieve the equivalent stress path in the p–q stress space to obtain the 3D mechanical properties, and the stress path controlled by stress, strain, and a hybrid of stress and strain. Once the software of conventional triaxial apparatus was developed by the novel method, the measuring range of stress paths could be expanded greatly.
Mingshuai Zhu, Daniel Pastor–Galán, Matthijs A. Smit
et al.
Abstract The opening of oceans within accretionary orogens is important for understanding the Wilson cycle. The Mongol–Okhotsk Ocean (MOO) began opening within the early Paleozoic accretionary collage of the Central Asian Orogenic Belt (CAOB), representing a world‐class example to constrain the geodynamic history of ocean opening in accretionary orogens, but the kinematics and mechanisms associated to this process are highly debated. We report on a newly‐discovered bimodal volcanic suite and associated volcanic‐sediments that comprise part of the Altay‐Sayan Rift System, which indicate a widespread Early Devonian extensional event within the CAOB. This extension regime is attributed to a Devonian mantle plume, which is thought to have impinged upon and weakened the lithosphere of the Early Paleozoic collage, and drove the opening of the MOO. Opening of the MOO suggests continent breakup in accretionary orogens tends to focus along intervening weak orogenic lithosphere between the rigid microcontinents.
Abstract Significant uncertainties remain in the estimate of radiative forcing (RF) induced by land‐use change (LUC), partially attributable to the lack of reliable LUC data with a high spatiotemporal resolution. We implemented a high spatiotemporally resolved LUC data set in an earth system model (OSCAR) to examine the response of RF to LUC from 1982 to 2010 in China. Results were compared with the RF estimated using a low spatiotemporally resolved LUC inventory employed previously. The updated LUC data set reduces negative RF by −3.8% from 2000 to 2010 due to the changes in surface albedo subject to LU transition. The simulated mean RF driven by CO2 associated with LUC from 1982 to 2010 using a high spatiotemporally resolved LUC data set reached 0.074 W m−2, considerably higher than 0.022 W m−2 of mean RF derived from the low spatiotemporally resolved LUC inventory, implying increasing net RF and more substantial LUC induced warming.
Abstract Arc volcanoes, created by magma generated from the dehydration of subducting slabs, show great variability in their sizes and along‐arc spatial distributions. In this study, we address a fundamental question, namely, how do subduction zones and volcanic arcs respond to the subduction of “atypical” oceanic lithosphere. We investigate the correlation between the geographical location and volume of arc volcanoes and the subduction of linear oceanic features, including hotspot tracks, oceanic plateaus, volcanic ridges, mid‐oceanic ridges, arc volcano chains, and fracture zones, around the Pacific basin. We use multidisciplinary and complementary data sets (topography and bathymetry, seismology and volcano morphometry), and design new analytical and data processing methods. We analyze 35 oceanic linear features. The subduction of three oceanic plateaus and five hotspot chains are clearly associated with volcanism increase, whereas four hotspot chains are related to volcanic gaps. We propose that the patterns of volcanism increase or decrease related to these oceanic features depend on the interplay between chemical (potentially enhancing melting) and thermo‐mechanical (inhibiting melting) effects, and/or by the variations of the chemical signatures along hotspot chains. The subduction of volcanic ridges is generally associated with small increases in arc volcanism, which may be accounted for by the fact that these features are highly hydrated and therefore promote melt. The subduction of active mid‐oceanic ridges is generally associated with slab windows and arc volcano gaps. No clear inference is found for the subduction of inactive arc ridges.
As a fundamental preprocessing technique, remote sensing image motion deblurring is important for visual understanding tasks. Most conventional approaches formulate the image motion deblurring task as a kernel estimation. Because the kernel estimation is a highly ill-posed problem, many priors have been applied to model the images and kernels. Even though these methods have obtained relatively better performances, they are usually time-consuming and not robust for different conditions. To address this problem, we propose a multitask learning mechanism for remote sensing image motion deblurring in this article, which contains an image restoration subtask and an image texture complexity recognition one. First, we consider the image motion deblurring problem as a domain transformation problem, from the blurred domain to a clear one. Specifically, the blurred domain represents the data space consisted of blurring images, and the definition of clear domain is similar. Second, we design a novel weighted attention map loss to enhance the reconstruction capability of the restoration subbranch for difficult local regions. Third, based on the restoration subbranch, a recognition subbranch is incorporated into the framework to guide the deblurring process, which provides the auxiliary texture complexity information to help the optimization of restoration subbranch. Additionally, in order to optimize the proposed network, we construct three large-scale datasets, and each sample in the dataset contains a clear image, a blurred image, and its texture label obtained by corresponding texture complexity. Finally, the experimental results on three constructed datasets demonstrate the robustness and the effectiveness of the proposed method.
Peter Tian-Yuan Shih, Huijung Wang, Kuo-Wei Li
et al.
Interferometric SAR analysis with a time series of images obtained from satellite has been proven to be a useful monitoring scheme for geomorphological changes, particularly related to the vertical dimension. The success of this technique relies on the coherence between the images. This imposes severe challenges for applications in vegetated areas. In this study, the landslide process of a site located in Liugui, southern Taiwan, is investigated by a time series of SAR images collected from ALOS PALSAR and Sentinel 1A. This landslide monitoring site is heavily vegetated. From the Persistent Scattering (PS) analysis, ALOS PALSAR presented more extracted points. The wavelength of the band may be a decisive factor. The time series of ALOS images spans across the deadliest typhoon impacted Taiwan in recorded history, Typhoon Morakot on 8 August 2009. It is clear that there are more PS points extracted from the time series after the event as compared to before Typhoon Morakot. This is largely explained by the increase in the amount of bare earth after the disaster. From the interferometric SAR analysis, the development of headward erosion could be observed. Although the number of PS points is limited, the understanding of erosion and landslide progress in the area could still be improved while integrating with the digital elevation model collected with airborne lidar, historic aerial photos, and images collected with UAS (Unmanned Aviation Systems). Together with the in situ measurements, the colluvium depth ranges from 2 - 40 m in the area. The surface instability is expected to persist.
The Burris Gravity Meter™ manufactured by ZLS Corporation, Austin/Texas, USA, is based on the invention of L&R (L. LaCoste and A. Romberg): The ZLS (zero-length spring). A digital feedback system (range of about 50 mGal) is used to null the beam. Now, more than 120 gravity meters of this make exist worldwide and are used successfully in exploration, volcanology, geodetic work and surveying.The sensor is made of the well-known (L&R) metal-alloy zero-length spring providing a low drift characteristic. The drifts observed are comparable to L&R gravimeters and are less than 0.3 mGal per month, which is much lower than the drifts known for the fused quartz sensors.The dial is calibrated every 50 mGal over the entire 7000 mGal meter range. Since the gravity value is determined at these points, there are no periodic errors. By a fourth heater circuit temperature effects are totally avoided. The gravity meter is controlled via Bluetooth® either to a handheld computer (tablet) or a notebook computer.The feedback responds with high stability and accuracy. The nulling of the beam is controlled by the UltraGrav™ control system which incorporates an inherently linear PWM (pulse-width modulated) electrostatic feedback system. In order to improve the handling of the gravimeter we have developed two Windows based programs: AGESfield for single measurements and AGEScont for continuous readings. Keywords: Gravimeter, Micro-gravity measurements, Drift, Resolution, Single and continuous observations
Adriana Potra, Rosemary Hickey-Vargas, Andrew W. Macfarlane
et al.
Análisis isotópicos de Pb, Sr y Nd de rocas mesozoicas y cenozoicas de la parte sur del terreno Guerrero en México contribuyen una mejor comprensión de su origen. Rocas metamórficas colectadas al sur de Arteaga (terreno Zihuatanejo) tienen valores isotópicos de Pb similares a los de rocas del basamento del Nevado de Toluca, indicando una posible conexión del basamento en esas áreas. Las relaciones isotópicas de Pb de rocas de los terrenos Guerrero del Mesozoico y Mixteca del Paleozoico son similares a las de los complejos Olmos del Mesozoico y Marañón del Paleozoico del Perú, pero más rediogénicas que las del basamento de edad grenvilliana del sureste de México (complejo Guichicovi) y del norte de Colombia (macizos Garzón y Santa Marta).
Las relaciones isotópicas actuales de Pb, Sr y Nd de rocas sedimentarias mesozoicas definen dos grupos: rocas de la región de Huetamo (terreno Zihuatanejo) con firmas isotópicas menos evolucionadas, y rocas del cinturón costero (áreas de Colima y Purificación en el terreno Zihuatanejo) y del área de Teloloapan (terreno Teloloapan) con relaciones isotópicas más elevadas. Las relaciones isotópicas de Pb, Sr y Nd sugieren la participación de un componente más evolucionado, posiblemente las rocas del basamento, en la generación de las rocas sedimentarias del cinturón costero y de la región al sur del área de Teloloapan, en comparación con las rocas sedimentarias del área de Huetamo.
Las rocas plutónicas cenozoicas de La Verde tienen relaciones isotópicas más radiogénicas que las muestras de Inguarán, El Malacate y La Esmeralda. Esas diferencias pueden ser el resultado de la asimilación de diferentes rocas (complejo Arteaga o rocas sedimentarias) o de distintos grados de contaminación. Valores isotópicos iniciales de Sr y Nd de los granitoides cretácicos de Manzanillo y Jilotlán grafican muy cerca de las muestras ígneas de Inguarán, El Malacate y La Esmeralda. Esta similaridad puede indicar que esas rocas tienen una fuente común. La composición isotópica de las rocas plutónicas cenozoicas es consistente con magmatismo relacionado a subducción y sugiere la participación de material cortical por procesos de asimilación durante el ascenso del magma o de incorporación de sedimentos subducidos, o ambos.
Radioactive materials from the accident at Fukushima Dai-ichi nuclear power
plant (FNPP) in March 2011 spread over a large area, increasing the
atmospheric electric conductivity by their ionizing effect, and reducing the
vertical (downward) component of the DC electric field near the ground, or
potential gradient (PG). PG data at Kakioka, 150 km away from the FNPP,
showed independent changes compared to the radiation dose rate, and a
comparison of these data revealed the local dynamics of the radioactive dust.
<br><br>
(1) The initial drop of the PG to almost zero during 14–15 March is
most likely due to radioactive dust suspended in the air near the ground
during cloudy weather. (2) An episode of PG increase to more than 50 V m<sup>−1</sup> on
16 March is most likely due to the re-suspension of the radioactive dust from
the surface and subsequent removal from Kakioka by the strong wind from the
non-contaminated area. (3) Low but finite values of the PG during 16–20 March
most likely reflect a reduced amount of radioactive material near the ground
after the above wind transported away the majority of the suspended
radioactive dust. (4) Very low values of the PG after substantial rain on
20–22 March most likely reflect settlement of the radioactive material by
rain-induced fallout. (5) Temporal recovery of daily variations from the end
of March to the middle of April with low nighttime fair-weather baseline PG
most likely reflects re-suspension of the radioactive dust into the air from
the ground and trees, and subsequent transport to the other region or fallout
to the ground until late April. (6) Weakening of the daily variation and
gradual recovery of the nighttime fair-weather baseline after mid-April
suggests a complete settlement of the radioactive material to the ground with
partial migration to the subsurface.