Preprints
Filtering by Subject: Environmental Sciences
Verifying pore network models of imbibition in rocks using time-resolved synchrotron imaging
Published: 2019-10-25
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Oil, Gas, and Energy, Physical Sciences and Mathematics
At the pore scale, slow invasion of a wetting fluid in porous materials is often modelled with quasi-static approximations which only consider capillary forces in the form of simple pore filling rules. The appropriateness of this approximation, often applied in pore network models, is contested in literature, reflecting the difficulty of predicting imbibition relative permeability with these [...]
On the difficulties of being rigorous in environmental geochemistry studies: some recommendations for designing an impactful paper
Published: 2019-10-25
Subjects: Biogeochemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Sciences, Geochemistry, Other Environmental Sciences, Physical Sciences and Mathematics
There have been numerous environmental geochemistry studies using chemical, geological, ecological and toxicological methods but each of these fields requires more subject specialist rigour than has generally been applied so far. Field-specific terminology has been misused and the resulting interpretations rendered inaccurate. In this paper, we propose a series of suggestions, based on our [...]
Machine Learning for Inferring CO2 Fluxes: The New Metaphysics of Neural Nets
Published: 2019-10-24
Subjects: Earth Sciences, Environmental Sciences, Other Earth Sciences, Physical Sciences and Mathematics
The advent of direct high-resolution global surface measurements of CO2 from the recently launched NASA Orbiting Carbon Observatory (OCO-2) satellite offers an opportunity to improve the estimate of Net Ecosystem Exchange (NEE) over land. Long-term measurements of CO2flux obtained from eddy covariance instruments on Flux towers show large annual differences with NEE calculated by inverse methods [...]
PYRENAIC ROCK GLACIERS: AN AIRBORNE AND MULTITEMPORAL LiDAR MONITORING CASE STUDY IN THE BESIBERRI AREA
Published: 2019-10-24
Subjects: Earth Sciences, Environmental Sciences, Geology, Geomorphology, Glaciology, Physical Sciences and Mathematics
The monitoring of rock glaciers is a current subject of interest because of its application as permafrost indicator and its sensitivity to climatic changes (especially temperature and precipitation). Alpine rock glaciers in the Pyrenees have been described by various authors, but to study them regionally has been a challenge since most of these studies are based on ground-based techniques. Two [...]
River inflow dominates methane emissions in an Arctic coastal system
Published: 2019-10-13
Subjects: Biogeochemistry, Earth Sciences, Environmental Monitoring, Environmental Sciences, Fresh Water Studies, Geochemistry, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Measurements of greenhouse gases in Arctic waters are strongly biased toward low-ice summer conditions, with few observations during periods of seasonal ice retreat. We present a year-round time series of dissolved methane (CH4) and nitrous oxide (N2O), along with targeted observations during ice melt of CH4 and carbon dioxide (CO2) in a river and estuary adjacent to Cambridge Bay, Nunavut, [...]
Lower threshold for marsh drowning suggests loss of microtidal marshes regardless of sediment supply
Published: 2019-10-10
Subjects: Earth Sciences, Environmental Sciences, Geomorphology, Natural Resources and Conservation, Physical Sciences and Mathematics
Salt marshes are simultaneously among the most valuable and vulnerable ecosystems in the world. We use a simplified formulation for sediment transport across marshes to explain why marshes are most vulnerable to sea level rise (SLR) in microtidal environments. We find inorganic sediment decay length scales with tidal range so that inorganic deposition is very low in the interior of microtidal [...]
Redox-informed models of global biogeochemical cycles
Published: 2019-10-07
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
Microbial activity mediates the global flow of carbon, oxygen, nitrogen, and other elements, including climatically significant gases. However, non-photosynthetic microbial activity is typically not resolved dynamically or mechanistically in global models of the marine and terrestrial biospheres, inhibiting predictive capability. Understanding the global-scale impact of complex microbial [...]
Climate change resilient agricultural practices: A learning experience from indigenous communities over India
Published: 2019-10-06
Subjects: Agriculture, Biodiversity, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Life Sciences, Physical Sciences and Mathematics, Sustainability
The impact of climate change on agricultural practices is rising question marks on future food security of billions of people in tropical and sub-tropical region. Recently introduced, Climate Smart Agriculture (CSA) techniques encourages the practices of sustainable agriculture, increasing adaptive capacity and resilience to shocks at multiple levels. However, in reality, it is extremely [...]
The water planetary boundary: interrogation and revision
Published: 2019-10-03
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics
The planetary boundaries framework has proven useful for many global sustainability contexts, but is challenging to apply to freshwater, which is spatially heterogeneous, part of complex socio-ecological systems and often dominated by local dynamics. To date, the planetary boundary for water has been simplistically defined by as the global rate of blue water consumption, functioning as a proxy [...]
Integrating the water planetary boundary with water management from local to global scales
Published: 2019-10-03
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics, Sustainability, Water Resource Management
The planetary boundaries framework defines the ‘safe operating space for humanity’ represented by nine global processes which can destabilize the Earth System if perturbed. The water planetary boundary attempts to provide a global limit to anthropogenic water cycle modifications, but it has been challenging to translate and apply it to the regional and local scales at which water problems and [...]
Holocene relative sea-level changes and glacial isostatic adjustment of the U.S. Atlantic coast
Published: 2019-09-30
Subjects: Climate, Earth Sciences, Environmental Sciences, Geomorphology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Tectonics and Structure
The first quality-controlled Holocene sea-level database for the U.S. Atlantic coast has been constructed from 686 sea-level indicators. The database documents a decreasing rate of relative sea-level (RSL) rise through time with no evidence of sea level being above present in the middle to late Holocene. The highest rates of RSL rise are found in the mid-Atlantic region. We employ the database to [...]
Mercury loading within the Selenga River Basin and Lake Baikal, Siberia
Published: 2019-09-28
Subjects: Biogeochemistry, Earth Sciences, Environmental Sciences, Geochemistry, Physical Sciences and Mathematics
Mercury (Hg) loading in Lake Baikal, a UNESCO world heritage site, is growing and poses a serious health concern to the lake’s ecosystem due to the ability of Hg to transform into a toxic form, known as methylmercury (MeHg). Monitoring of Hg into Lake Baikal is spatially and temporally sparse, highlighting the need for insights into historic Hg loading. This study reports measurements of Hg [...]
Hydropower dependency and climate change in sub-Saharan Africa: A nexus framework and evidence-based review
Published: 2019-09-06
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Environmental Studies, International and Area Studies, Physical Sciences and Mathematics, Social and Behavioral Sciences
In sub-Saharan Africa, 160 million grid-connected electricity consumers live in countries where hydropower accounts for over 50% of total power supply. A warmer climate with more frequent and intense extremes could result in supply reliability issues. Here, (i) a robust framework to highlight the interdependencies between hydropower, water availability, and climate change is proposed, (ii) the [...]
Building back bigger in hurricane strike zones
Published: 2019-09-03
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Environmental Sciences, Geomorphology, Physical Sciences and Mathematics, Sustainability
Despite decades of regulatory efforts in the United States to decrease vulnerability in developed coastal zones, exposure of residential assets to hurricane damage is increasing — even in places where hurricanes have struck before. Comparing plan-view footprints of individual residential buildings before and long after major hurricane strikes, we find a systematic pattern of ‘building back [...]
The near-tip region of a hydraulic fracture with pressure-dependent leak-off and leak-in
Published: 2019-09-03
Subjects: Earth Sciences, Engineering, Environmental Sciences, Hydrology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Volcanology
This paper is concerned with an analysis of the near tip region of a propagating fluid-driven fracture in a saturated permeable rock. The study attempts to accurately resolve the coupling between the physical processes - rock breakage, fluid pressure drop in the viscous fluid flow in the fracture, and fluid exchange between fracture and the rock - that exert influence on the hydraulic fracture [...]