Preprints
There are 5938 Preprints listed.
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 [...]
Initiation of deposition in supercritical turbidity currents downstream of a slope break.
Published: 2022-07-07
Subjects: Earth Sciences
Turbidity currents flowing across the ocean floor encounter changes of the local bathymetry including abrupt reductions in slope gradient also known as slope breaks. Turbidity currents flowing across a slope break will change their flow dynamics and may start to deposit as a consequence. Previous experiments on turbidity currents crossing a slope break have indeed observed abrupt changes of flow [...]
Global water cycle shifts far beyond pre-industrial conditions – planetary boundary for freshwater change transgressed
Published: 2022-07-07
Subjects: Hydrology
Human actions compromise the many life-supporting functions provided by the freshwater cycle. Yet, scientific understanding of anthropogenic freshwater change and its long-term evolution is limited. Using a multi-model ensemble of global hydrological models, we estimate how, over a 145-year industrial period, streamflow and soil moisture have deviated from pre-industrial baseline conditions [...]
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 [...]
Reconstructing Rotomahana Basin topography to disclose the lost White Terraces─ New Zealand’s Eighth Wonder of the World
Published: 2022-07-05
Subjects: Geographic Information Sciences, Geomorphology, Other Earth Sciences, Other Environmental Sciences, Physical and Environmental Geography, Spatial Science, Stratigraphy, Volcanology
The greatest geoscience and tourist attractions in the southern hemisphere were the Pink and White Terraces, the lost Eighth Wonder of the World. British, American and European tourists bypassed local calcareous terraces, for the sea voyage to New Zealand where the siliceous terraces astonished a global audience. Their allure remains. In 1886, the Mount Tarawera eruption buried the terraces. They [...]
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 Lock-Down Effects of COVID-19 on the Air Pollution Indices in Iran and Its Neighbors
Published: 2022-07-02
Subjects: Applied Statistics, Environmental Public Health, Environmental Sciences, Environmental Studies, Near and Middle Eastern Studies, Other Statistics and Probability, Statistical Methodology, Statistical Models
Introduction The Covid-19 restrictions have a lot of various peripheral negative and positive effects like economic shocks and decreasing air pollution, respectively. Many studies showed NO2 reduction in most parts of the world. Method Iran and its land and maritime neighbors have about 7.4% of the world population and 6.3% and 5.8% of World COVID-19 cases and deaths, respectively. The air [...]
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% [...]
Developing seagrass index for long term monitoring of Zostera japonica seagrass bed: a case study in Yellow River Delta, China
Published: 2022-06-30
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Geographic Information Sciences, Geography, Physical and Environmental Geography, Remote Sensing
Seagrass beds offer unique and vital ecological services as an important blue carbon ecosystem in coastal wetlands. Zostera japonica is an intertidal seagrass species native to eastern Asia and is one of the most widely distributed seagrass species in China. However, little is known on the long-term variations of Z. japonica extents. Automatic mapping method for Z. japonica seagrass beds is in [...]
Towards Robust River Plastic Detection: Combining Lab and Field-based Hyperspectral Imagery
Published: 2022-06-29
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Hydrology, Statistical Models
Plastic pollution in aquatic ecosystems has increased dramatically in the last five decades, with strong impacts on human and aquatic life. Recent studies endorse the need for innovative approaches to monitor the presence, abundance, and types of plastic in these ecosystems. One approach gaining rapid traction is the use of multi- and hyperspectral cameras. However, most experiments using this [...]
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 [...]
The Eighth Wonder of the World in New Zealand─ the third, Black Terrace
Published: 2022-06-28
Subjects: Geology, Geomorphology, Other Earth Sciences, Other Environmental Sciences, Other Planetary Sciences, Stratigraphy, Volcanology
The greatest tourism and geoscience attraction in the southern hemisphere, in the nineteenth century were the siliceous Pink and White Terraces, the lost Eighth Wonder of the World in New Zealand. In 1886, the Mount Tarawera eruption buried the terraces. In the absence of any government survey or evidence of their locations or destruction; debate over their survival continued until the 1940s. [...]
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 [...]