Preprints
There are 4725 Preprints listed.
No support for carbon storage of >1000 GtC in northern peatlands
Published: 2019-12-04
Subjects: Biogeochemistry, Earth Sciences, Physical Sciences and Mathematics
Northern peatlands store large amounts of carbon (C) and have played an important role in the global carbon cycle since the Last Glacial Maximum. Most northern peatlands have established since the end of the deglaciation and accumulated C over the Holocene, leading to a total present-day stock of 500 ± 100 GtC. This is a consolidated estimate, emerging from a diversity of methods. Recently, [...]
Local and remote influences on the heat content of Southern Ocean mode water formation regions.
Published: 2019-12-04
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The Southern Ocean (SO) is a crucial region for the global ocean uptake of heat and carbon. There are large uncertainties in the observations of fluxes of heat and carbon between the atmosphere and the ocean mixed layer, which leads to large uncertainties in the amount entering into the global overturning circulation. In order to better understand where and when fluxes of heat and momentum have [...]
Accelerating numerical wave-propagation using wavefield adapted meshes, Part I: Forward and adjoint modelling
Published: 2019-12-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
An order of magnitude speed-up in finite-element modelling of wave propagation can be achieved by adapting the mesh to the anticipated space-dependent complexity and smoothness of the waves. This can be achieved by designing the mesh not only to respect the local wavelengths, but also the propagation direction of the waves depending on the source location, hence by anisotropic adaptive mesh [...]
The economic implications of using a truly preindustrial climate baseline
Published: 2019-12-04
Subjects: Climate, Geography, Human Geography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Social and Behavioral Sciences
The pervasive impacts of climate change can result in scientific decisions having unforeseen societal implications. To demonstrate this, we explore the global and regional economic implications of adopting an earlier preindustrial baseline of 1400-1800 for climate policy targets instead of the commonly used early industrial period of 1850-1900 for which we have observational data. Because of [...]
Bayesian Models for Deriving Biogeochemical Information from Satellite Ocean Color
Published: 2019-12-04
Subjects: Life Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
In this study, we present Bayesian machine learning approaches to predict the spectral phytoplankton absorption coefficient - a proxy of phytoplankton biomass - from top of atmosphere measurements of ocean color. This presents a significant advance in ocean color research as it permits the bypassing of conventional atmospheric correction, which is notoriously challenging in optically complex [...]
Optical wave gauging using deep neural networks
Published: 2019-12-04
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Geomorphology, Physical Sciences and Mathematics
We develop a remote wave gauging technique to estimate wave height and period from imagery of waves in the surf zone. In this proof-of-concept study, we apply the same framework to three datasets: the first, a set of close-range monochrome infrared (IR) images of individual nearshore waves at Duck, NC, USA; the second, a set of visible (i.e. RGB) band orthomosaics of a larger nearshore area near [...]
Abrupt Arctic Warming Repeatedly Led to Prolonged Drought and Glacial Retreat in the Tropical Andes During the Last Glacial Cycle
Published: 2019-12-04
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Sedimentology
A sediment core spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes reveals abrupt climatic events on a centennial-millennial time scale. These events, which involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake, occurred during the abrupt warmings recorded in [...]
Fossil fuel combustion is driving indoor CO2 toward levels harmful to human cognition
Published: 2019-12-04
Subjects: Climate, Cognitive Neuroscience, Life Sciences, Neuroscience and Neurobiology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Human activities are elevating atmospheric carbon dioxide concentrations to levels unprecedented in human history. The majority of anticipated impacts of anthropogenic CO2 emissions are mediated by climate warming. Recent experimental studies in the fields of indoor air quality and cognitive psychology and neuroscience, however, have revealed significant direct effects of indoor CO2 levels on [...]
A 2,000-year Bayesian NAO reconstruction from the Iberian Peninsula
Published: 2019-11-27
Subjects: Applied Statistics, Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics, Statistics and Probability
The North Atlantic Oscillation (NAO) is the major atmospheric mode that controls winter European climate variability because its strength and phase determine regional temperature, precipitation and storm tracks. The NAO spatial structure and associated climatic impacts over Europe are not stationary making it crucial to understanding its past evolution in order to improve the predictability of [...]
Wind-driven evolution of the North Pacific subpolar gyre over the last deglaciation
Published: 2019-11-27
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
North Pacific atmospheric and oceanic circulations are key missing pieces in our understanding of the reorganisation of the global climate system since the Last Glacial Maximum (LGM). Here, using a basin-wide compilation of planktic foraminiferal oxygen isotopes, we show that the North Pacific subpolar gyre extended ~3° further south during the LGM, consistent with sea surface temperature and [...]
Urban Near-surface Seismic Monitoring using Distributed Acoustic Sensing
Published: 2019-11-27
Subjects: Civil and Environmental Engineering, Civil Engineering, Earth Sciences, Engineering, Geophysics and Seismology, Physical Sciences and Mathematics
Urban subsurface monitoring requires high temporal-spatial resolution, low maintenance cost, and minimal intrusion to nearby life. Distributed acoustic sensing (DAS), in contrast to conventional station-based sensing technology, has the potential to provide a passive seismic solution to urban monitoring requirements. Based on data recorded by the Stanford Fiber Optic Seismic Observatory, we [...]
Effects of off-fault inelasticity on near-fault directivity pulses
Published: 2019-11-27
Subjects: Civil and Environmental Engineering, Engineering, Geotechnical Engineering
Near-fault motion is often dominated by long-period, pulse-like particle velocities with fault-normal polarization that, when enhanced by directivity, may strongly excite mid- to high-rise structures. We assess the extent to which plastic yielding may affect amplitude, frequency content, and distance scaling of near-fault directivity pulses. Dynamic simulations of 3D strike-slip ruptures reveal [...]
Plants as sensors: vegetation response to rainfall predicts subsurface water storage capacity in Mediterranean climates
Published: 2019-11-23
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Methods are lacking to characterize critical zone (CZ) structure at spatial scales relevant to earth system and dynamic global vegetation models. This knowledge gap results in poor quantification of CZ plant-available water storage capacity, hindering realistic prediction of the response of plants and streamflow to anticipated changes in the hydrological cycle. Here, we exploit the phase offset [...]
Effects of groundwater pumping on ground surface temperature: A regional modeling study in the North China Plain
Published: 2019-11-23
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Over-exploitation of groundwater (GW) in the North China Plain (NCP) since the 1960s has many environmental consequences. However, understanding of the dominant mechanisms remains limited, particularly at the regional scale. In this study, the coupled ParFlow.CLM model representing subsurface and land-surface processes and their interactions was applied in the NCP at high spatio-temporal [...]
A grid for multidimensional and multivariate spatial representation and data processing.
Published: 2019-11-23
Subjects: Computer Sciences, Earth Sciences, Geophysics and Seismology, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics
Researchers use 2D and 3D spatial models of multivariate data of differing resolutions and formats. It can be challenging to work with multiple datasets, and it is time consuming to set up a robust, performant, grid to handle such spatial models. We share a Python module that provides a framework for containing multidi- mensional data and functionality to work with those data. The module provides [...]