Preprints
Filtering by Subject: Physical Sciences and Mathematics
Climate-Driven Risk of Extreme Wildfire in California
Published: 2022-07-09
Subjects: Physical Sciences and Mathematics
California has experienced increased instances of extreme wildfire behavior in recent years, but the extent to which this is due to anthropogenic warming has been difficult to determine. Here we quantify empirical relationships between temperature and the risk of extreme daily wildfire growth (>10,000 acres) in California and use these relationships to estimate how extreme growth risk is changing [...]
Machine-learning correction of the local effects on neutron monitor and muon detector count rates at Syowa Station in the Antarctic
Published: 2022-07-09
Subjects: Physical Sciences and Mathematics
Solar modulation of galactic cosmic rays around the solar minimum in 2019-2020 looks different in the secondary neutrons and muons observed at the ground. To compare the solar modulation of primary cosmic rays in detail, we must remove the possible seasonal variations caused by the atmosphere and surrounding environment. As such surrounding environment effects, we evaluate the snow cover effect [...]
Mantle flow pattern associated with the Patagonian slab window determined from azimuthal anisotropy
Published: 2022-07-08
Subjects: Earth Sciences, Physical Sciences and Mathematics
Geological processes in Southern Patagonia are affected by the Patagonian slab window, formed by the subduction of the Chile Ridge and subsequent northward migration of the Chile Triple Junction. Using shear wave splitting analysis, we observe strong splitting of up to 2.5 s with an E-W fast direction just south of the triple junction and the edge of the subducting Nazca slab. This region of [...]
The Role of Salt Tectonics in the Energy Transition: An Overview and Future Challenges
Published: 2022-07-07
Subjects: Physical Sciences and Mathematics
The fundamental properties of salt have long been exploited in the search for hydrocarbons, as they influence many of the hydrocarbon play elements. This industrial application has driven the pursuit of salt tectonic knowledge over the last century and led to major conceptual advances in the field. However, the current need, and social-political demand, to decarbonize suggests that the [...]
Mercury stable isotope composition of lichens and mosses from northern Eurasia
Published: 2022-07-07
Subjects: Physical Sciences and Mathematics
Mercury (Hg) concentrations in lichens and mosses can be used as surrogates for atmospheric Hg deposition to continental surfaces. In this study we collected and analyzed Hg concentrations and isotopic composition of epiphytic tree lichens and terricolous lichens and mosses from remote locations across the Eurasian Arctic and sub-Arctic (50 to 72o N, 30 to 180o E). Total Hg (THg) concentrations [...]
A geothermal heat flow model of Africa based on Random Forest Regression
Published: 2022-07-06
Subjects: Physical Sciences and Mathematics
We generate a geothermal heat flow model over Africa using random forest regression based on sixteen different geophysical and geological quantities (among them are Moho depth, Curie temperature depth, gravity anomalies, topography, and seismic wave velocities). The training of the random forest is based on direct heat flow measurements collected in the compilation of Lucazeau (2019). The final [...]
Identifying potential hotspots of land use/land cover change in the last 3 decades, Uttarakhand, NW Himalaya
Published: 2022-07-05
Subjects: Physical Sciences and Mathematics
Uttarakhand region in the NW Himalaya has experienced two extreme climatic-geomorphic events within last 10 years that killed more than 6000 people. Though these events, like many others in the Himalaya, have been attributed to climate-change and anthropogenic disturbances, identification of potential hotspots of land use/land cover change is rarely attempted to make future inferences for [...]
Pore-scale imaging of hydrogen displacement and trapping in porous media
Published: 2022-07-04
Subjects: Physical Sciences and Mathematics
Hydrogen can act as an energy store to balance supply and demand in the renewable energy sector. Hydrogen storage in subsurface porous media could deliver high storage capacities but the volume of recoverable hydrogen is unknown. We imaged the displacement and capillary trapping of hydrogen by brine in a Clashach sandstone cylinder at 2-7 MPa pore fluid pressure using X-ray computed [...]
Seismic interferometry in the presence of an isolated noise source
Published: 2022-07-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Seismic interferometry gives rise to a correlation wavefield that is closely related to the Green's function under the condition of uniformly distributed noise sources. In the presence of an additional isolated noise source, a second contribution to this wavefield is introduced that emerges from the isolated source location at negative lapse time. These two contributions interfere, which may bias [...]
The root to the Galápagos mantle plume on the core-mantle boundary
Published: 2022-07-01
Subjects: Earth Sciences, Physical Sciences and Mathematics
Ultra-low velocity zones (ULVZs) are thin anomalous patches on the boundary between the Earth's core and mantle, revealed by their effects on the seismic waves that propagate through them. Here we map a broad ULVZ near the Galápagos hotspot using shear-diffracted waves. Forward modelling assuming a cylindrical shape shows the patch is ~600 km wide, ~20 km high, and its shear velocities are ~25% [...]
Mid- and long-chain leaf wax δ2H values in modern plants and lake sediments from mid-latitude North America
Published: 2022-06-28
Subjects: Physical Sciences and Mathematics
Compound-specific δ2H values of leaf wax n-alkanes are increasingly being used to infer past hydroclimates. However, differences in n-alkane production and apparent fractionation factors (εapp) among different plant groups complicate the relationships between n-alkane δ2H values and those of environmental water. Mid- and long-chain n-alkanes in sedimentary archives (i.e., n-C23 and n-C29) are [...]
Distinct roles of cyclones and anticyclones in setting the midwinter minimum of the North Pacific eddy activity: a Lagrangian perspective
Published: 2022-06-27
Subjects: Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The North Pacific storm-track activity is suppressed substantially under the excessively strong westerlies to form a distinct minimum in midwinter, which seems inconsistent with linear baroclinic instability theory. This “midwinter minimum” of the storm-track activity has been intensively investigated for decades as a test case for storm-track dynamics. However, the mechanisms controlling it are [...]
Advecting Superspecies: Efficiently Modeling Transport of Organic Aerosol with a Mass-Conserving Dimensionality Reduction Method
Published: 2022-06-26
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Engineering, Environmental Chemistry, Environmental Engineering, Environmental Sciences, Other Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The chemical transport model LOTOS-EUROS uses a volatility basis set (VBS) approach to represent the formation of secondary organic aerosol (SOA) in the atmosphere. Inclusion of the VBS approximately doubles the dimensionality of LOTOS-EUROS and slows computation of the advection operator by a factor of two. This complexity limits SOA representation in operational forecasts. We develop a [...]
Controls on grain size distribution in an ancient sand sea
Published: 2022-06-25
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Sedimentology
Grain size distribution in deserts is driven by a combination of autogenic controls such as grain abrasion and sorting due to wind transport and allogenic controls such as provenance and spatial changes in wind-direction. Downwind grain-size trends in present day sand seas display contrasting results. For example, the Namib and Hexi Corridor sand seas show broad downwind fining and sorting [...]
Evolution of diversity in the editorial boards of Geochimica et Cosmochimica Acta and Chemical Geology
Published: 2022-06-24
Subjects: Geochemistry, Physical Sciences and Mathematics
Background: Editorial board members of academic journals are often considered gatekeepers of knowledge and role models for the community. Editorial boards should have sufficiently diverse backgrounds to facilitate the publication of manuscripts with a wide range of research paradigms, methods, and cultural perspectives. Objectives: This study critically evaluates changes in the representation of [...]