Preprints
Filtering by Subject: Physical Sciences and Mathematics
Harnessing hyperspectral imagery to map surface water presence and hyporheic flow properties of headwater stream networks
Published: 2022-10-15
Subjects: Physical Sciences and Mathematics
Growth and contraction of headwater stream networks determine the extent and quality of ecologically critical habitat, and open a window into the storage dynamics of catchments. A fundamental challenge is observation of the process itself: wetted channel extent is highly dynamic in space and time, with the length of wetted channel sometimes varying by orders of magnitude over the course of a [...]
On spatially correlated observations in a particle method for subsidence estimation
Published: 2022-10-13
Subjects: Engineering, Physical Sciences and Mathematics
The particle method is an ensemble-based data assimilation method for state- and parameter estimation in a quasi-static problem. We apply the particle method in two different experiments with models of increasing complexity. The first model, which calculates subsidence for a single observation point due to a single source of strain, considers uncorrelated parameters and observations. In the [...]
The cryptic stratigraphic record of the syn- to post-rift transition in the offshore Campos Basin, SE Brazil
Published: 2022-10-12
Subjects: Physical Sciences and Mathematics
Rift basins typically comprise three main tectono-stratigraphic stages; pre-, syn-, and post-rift. The syn-rift stage is often characterised by the deposition of asymmetric wedges of growth strata that record differential subsidence caused by active normal faulting. The subsequent post-rift stage is defined by long-wavelength subsidence driven by lithospheric cooling, and is typified by the [...]
Bayesian inference on the initiation phase of the 2014 Iquique, Chile, earthquake
Published: 2022-10-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We investigate the initiation phase of the 2014 Mw8.1 Iquique earthquake in northern Chile. In particular, we focus on the month preceding the mainshock, a time period known to exhibit an intensification of the seismic and aseismic activity in the region. The goal is to estimate the time-evolution and partitioning of seismic and aseismic slip during the preparatory phase of the mainshock. To do [...]
Origin, transport, accumulation of methane in sedimentary basins revisited
Published: 2022-10-02
Subjects: Physical Sciences and Mathematics
The current widely accepted models for generation of methane by thermal cracking of oil and by bacterial fermentation have several serious inconsistencies. Experiments show that high-temperature pyrolysis of liquid (C6+) hydrocarbons does not produce methane even if hydrogen is added to the feed, and condensate, which is generally assumed to be the direct precursor to methane, generally amounts [...]
Modeling Stratospheric Polar Vortex Variation and Identifying Vortex Extremes Using Explainable Machine Learning
Published: 2022-10-01
Subjects: Physical Sciences and Mathematics
The winter stratospheric polar vortex (SPV) exhibits considerable variability in magnitude and structure, which can result in extreme SPV events. These extremes can subsequently influence weather in the troposphere from weeks to months and thus are important sources of surface predictability. However, the predictability of the SPV extreme events is limited to 1-2 weeks in state-of-the-art [...]
Global groundwater warming
Published: 2022-10-01
Subjects: Earth Sciences, Physical Sciences and Mathematics
Aquifers contain the largest store of unfrozen freshwater, making groundwater critical for life on Earth. Groundwater temperatures infl uence stream thermal regimes, groundwater-dependent ecosystems, aquatic biogeochemical processes, water quality, and the geothermal potential. Yet little is known about how groundwater responds to surface warming across spatial and temporal scales. We simulate [...]
Post-salt magmatism in the Campos Basin, offshore SE Brazil: style, distribution, and relationship to salt tectonics
Published: 2022-09-28
Subjects: Physical Sciences and Mathematics
Substantial magmatism occurred during the development of the marginal basins of the central and southern South Atlantic. Situated on the Brazilian side of the central segment, the Campos and Santos basin represent a transitional margin, located between the magma-rich margin in the north and the magma-poor margin in the south. In addition to magmatism associated with the initiation of continental [...]
Cautionary tales from the mesoscale eddy transport tensor
Published: 2022-09-26
Subjects: Physical Sciences and Mathematics
The anisotropic mesoscale eddy transport tensor is diagnosed using passive tracers advected in both an idealized 101-member mesoscale-resolving quasi-geostrophic (QG) double-gyre ensemble, and a realistic 24-member eddying ($1/12^\circ$) ensemble of the North Atlantic. We assert that the Reynold's decomposition along the ensemble dimension, rather than the spatial or temporal dimension, allows us [...]
All aboard! Earth system investigations with the CH2O-CHOO TRAIN v1.0
Published: 2022-09-24
Subjects: Climate, Earth Sciences, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Models of the carbon cycle and climate on geologic (>10^4 year) timescales have improved tremendously in the last 50 years due to parallel advances in our understanding of the Earth system and the increase in computing power to simulate its key processes. Despite these advances, balancing the Earth System's vast complexity with a model's computational expense is a primary challenge in model [...]
CloudSEN12 - a global dataset for semantic understanding of cloud and cloud shadow in Sentinel-2
Published: 2022-09-24
Subjects: Computer Sciences, Earth Sciences, Physical Sciences and Mathematics
Accurately characterizing clouds and their shadows is a long-standing problem in the Earth Observation community. Recent works showcase the necessity to improve cloud detection methods for imagery acquired by the Sentinel-2 satellites. However, the lack of consensus and transparency in existing reference datasets hampers the benchmarking of current cloud detection methods. Exploiting the [...]
Intra-channel detachment in a collisional orogen: the Jhala Normal Fault in the Bhagirathi river section, Garhwal Higher Himalaya, India
Published: 2022-09-24
Subjects: Physical Sciences and Mathematics
In the Bhagirathi River Transect of the Garhwal Himalaya, India, the existence of the Jhala Normal Fault (JNF) and its movement sense are disputed. The JNF has been considered either as part of the South Tibetan Detachment System (STDS) or as a distinct, more southerly discontinuity within the Higher Himalayan Crystalline Sequence (HHCS). Field studies reveal that the JNF lies entirely within the [...]
Complex evolution of the 2016 Kaikoura earthquake revealed by teleseismic body waves
Published: 2022-09-23
Subjects: Physical Sciences and Mathematics
The 2016 Kaikoura earthquake, New Zealand, ruptured more than a dozen faults, making it difficult to prescribe a model fault for analysing the event by inversion. To model this earthquake from teleseismic records, we used a potency density tensor inversion, which projects multiple fault slips onto a single model fault plane, which reduced the non-uniqueness due to the uncertainty in selecting the [...]
Marine Radiocarbon Calibration in Polar Regions: A Simple Approximate Approach using Marine20
Published: 2022-09-22
Subjects: Earth Sciences, Environmental Sciences, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistics and Probability
The Marine20 radiocarbon (14C) age calibration curve, and all earlier marine radiocarbon calibration curves from the IntCal group, must be used extremely cautiously for the calibration of marine 14C samples from polar regions (outside ~ 40ºS – 40ºN) during glacial periods. Calibrating polar 14C marine samples from glacial periods against any Marine calibration curve (Marine20 or any earlier [...]
Ocean heat uptake efficiency increase since 1970
Published: 2022-09-21
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The ocean stores the bulk of anthropogenic heat in the Earth system. The ocean heat uptake efficiency (OHUE) -- the flux of heat into the ocean per degree of global warming -- is therefore a key factor in how much warming will occur in the coming decades. In climate models, OHUE is well-characterised, tending to decrease on centennial timescales; in contrast, OHUE is not well-constrained from [...]