Preprints
There are 6976 Preprints listed.
Nutrient concentrations and nitrogen speciation in tropical watersheds of central Panama
Published: 2023-07-13
Subjects: Environmental Sciences
We present chemical analyses from rivers and streams in five partly to near-fully forested watersheds in the humid tropics of central Panama. Contrary to the situation observed for temperate watersheds in the Northern Hemisphere, the concentration of dissolved inorganic nitrogen in the Panamanian watersheds is low (mostly <2.6 µmol L-1), whereas concentrations of organic nitrogen are several [...]
Assisted upscaling of miscible CO¬2-enhanced oil recovery floods using an artificial-neural-network-based optimisation algorithm
Published: 2023-07-13
Subjects: Engineering, Other Engineering
The fine-scale compositional simulations required to accurately model miscible CO2 flooding are unrealistic and highly computationally expensive, and upscaling procedures are required to approximate the behaviour of these fine-scale grids on more realistic coarse-scale models. These procedures include the pseudoisation of relative permeabilities which ensures the matching of large-scale effects [...]
The interactions of instabilities during miscible CO2 enhanced oil recovery: A numerical simulation study
Published: 2023-07-13
Subjects: Petroleum Engineering, Transport Phenomena
During field-scale simulations of miscible displacements, the effect of heterogeneity-induced channelling is always accounted for, while micro-scale physical instabilities like viscous fingering and molecular diffusion are ignored due to the computational costs of the required fine-grid simulations. Thus, the interplay between small- and macro-scale physical instabilities is not properly [...]
Integrating Climate Risk into Long-Term Energy Planning: A Critical Review
Published: 2023-07-15
Subjects: Civil Engineering, Earth Sciences, Power and Energy, Risk Analysis
Electricity systems face substantial and growing climate risks which are escalating due to electrification, renewable energy intermittency, population changes, and the intensifying impacts of climate change such as extreme temperatures and weather-induced infrastructure damage. This critical review investigates climate risks to the electricity sector and scrutinizes the methodologies used to [...]
CLIMATIC DETERMINANTS OF COVID-19 CASES AND DEATHS IN UGANDA: 2020-2022
Published: 2023-07-14
Subjects: Risk Analysis
Background: Infectious diseases have proven to be among the greatest challenges to life in the Anthropocene era. Their repeated and cyclical occurrences coupled with varying variants, and rapidly changing climatic conditions within this century threaten to take the world back to the “pre-development era” in the absence of corrective measures. We designed a research study to determine the [...]
Last Glacial Maximum pattern effects reduce climate sensitivity estimates
Published: 2023-07-14
Subjects: Atmospheric Sciences, Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology
Here, we show that the Last Glacial Maximum (LGM) provides a stronger constraint on equilibrium climate sensitivity (ECS), the global warming from increasing greenhouse gases, after accounting for temperature patterns. Feedbacks governing ECS depend on spatial patterns of surface temperature (“pattern effects”); hence, using the LGM to constrain future warming requires quantifying how [...]
Regenerative Agriculture the Veganic Way: A Seven-year Research Study in Increasing Soil Organic Matter (SOM) and Crop Yields
Published: 2023-07-15
Subjects: Agriculture
Agriculture is a major contributor to greenhouse gas (GHG) emissions and biodiversity loss, mostly through deforestation for the cultivation of animal feeds; enteric fermentation from ruminants like cattle, fertilizers and manure; and soil degradation from intensive farming practices. There is currently a push to transform our farming systems to attempt to alleviate the almost-assured [...]
Climate Resilience of small-town water utilities in Eastern Ethiopia
Published: 2023-07-15
Subjects: Environmental Sciences
Building a resilient water, sanitation, and hygiene (WASH) system is more important than ever since climate change threatens WASH, particularly in low- and middle-income countries. The Government of Ethiopia stresses climate-resilient WASH through its One WASH National Program, albeit it may be challenging to ascertain the resilience due to the absence of an easy-to-use monitoring tool. The “How [...]
Application of Köppen Climate Classification of Two Remote Regions in Turkey
Published: 2023-07-21
Subjects: Oceanography and Atmospheric Sciences and Meteorology
This paper presents the application of the Köppen climate classification system for two remote regions in Turkey. The author describes the Köppen system and the history of climate classification briefly. The author uses the meteorological data of Mersin province in the Mediterranean region and Sinop province in the Black Sea region. The author compares the results with the existing classification [...]
Mapping Permafrost Variability and Degradation Using Seismic Surface Waves, Electrical Resistivity, and Temperature Sensing: A Case Study in Arctic Alaska
Published: 2023-07-19
Subjects: Civil Engineering, Geophysics and Seismology, Geotechnical Engineering, Hydrology
Subsurface processes significantly influence surface dynamics in permafrost regions, necessitating utilizing diverse geophysical methods to reliably constrain permafrost characteristics. This research uses multiple geophysical techniques to explore the spatial variability of permafrost in undisturbed tundra and its degradation in disturbed tundra in Utqiaġvik, Alaska. Here, we integrate multiple [...]
Waterflood-CMG production optimization analysis for the Draugen field of Norway
Published: 2023-07-18
Subjects: Engineering
The Draugen field is well-known for producing oil that is then transported to power plant facilities to generate electricity in Draugen. However, with declining oil production (as of 2021) and new necessary electrification contracts, the field may be unable to meet the demand for plant facilities. The current study combines waterflooding and reservoir simulation methods from the Computer [...]
Separating Internal and Forced Contributions to Near Term SST Predictability in the CESM2-LE
Published: 2023-07-18
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology
An open question in the study of climate prediction is whether internal variability will continue to contribute to prediction skill in the coming decades, or whether predictable signals will be overwhelmed by rising temperatures driven by anthropogenic forcing. We design an interpretable neural network that can be decomposed to examine the relative contributions of external forcing and internal [...]
Python workflow for segmenting multiphase flow in porous rocks
Published: 2023-07-25
Subjects: Engineering, Physical Sciences and Mathematics
The need for accurate, consistent and fast image processing has become an important part of the investigation of multiphase flow through porous media. We describe an open-source image processing workflow written in python, using the sci-kit toolbox. We demonstrate the methodology to segment multiple fluids (gas and brine), and the rock grains for a Bentheimer sandstone. This workflow can be [...]
High rates of rock organic carbon oxidation sustained as Andean sediment transits the Amazon foreland-floodplain
Published: 2023-07-18
Subjects: Biogeochemistry, Geochemistry
The oxidation of organic carbon contained within sedimentary rocks (“petrogenic” carbon, or hereafter OCpetro) emits nearly as much CO2 as is released by volcanism, thereby playing a key role in the long-term global C budget. High erosion rates in mountains have been shown to increase OCpetro oxidation. However, these settings also export un-weathered material that may continue to react in [...]
Commercial-Scale Demonstration of a First-of-a-Kind Enhanced Geothermal System
Published: 2023-07-18
Subjects: Engineering, Physical Sciences and Mathematics
Fervo Energy has completed construction of a commercial enhanced geothermal system (EGS) project and has qualified full functionality of the system through production testing at commercially relevant operating conditions. The project site is located in a nearfield setting adjacent to an operating geothermal power station in north-central Nevada and is designed to deliver an uplift in [...]