Preprints
Filtering by Subject: Environmental Sciences
Framework for consequential life cycle assessment of pyrolysis biorefineries: A case study for the conversion of primary forestry residues
Published: 2020-07-26
Subjects: Bioresource and Agricultural Engineering, Civil and Environmental Engineering, Engineering, Environmental Engineering, Environmental Indicators and Impact Assessment, Environmental Sciences, Physical Sciences and Mathematics, Sustainability
The development of bioeconomy needs to accelerate in order to get rid of fossil fuels and products. The production of bio-based products and renewable energy sources from the thermochemical conversion of biomass can be a sustainable alternative. Pyrolysis is one of the thermochemical processes that can convert biomass into liquid (bio-oil), solid (biochar) and gaseous (non-condensable gases) [...]
Overview of recent land cover changes in the biodiversity hotspots
Published: 2020-07-26
Subjects: Environmental Sciences, Natural Resources and Conservation, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sustainability
Biodiversity hotspots are the most biologically rich, yet threatened, terrestrial regions. From 1992 to 2015, they underwent 148 Mha of land cover changes, including forest losses (56 Mha, of which 40 Mha caused by agricultural expansion), declines of shrubland or savannah (23 Mha), and urbanization (10 Mha). The three largest losses in forest areas occurred in Sundaland, Indo-Burma, and [...]
Visualizing the daily evolution and extent of snow drought
Published: 2020-07-22
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Natural Resources Management and Policy, Physical Sciences and Mathematics
Snow droughts are commonly defined as below average snowpack at a point in time, typically 1 April in the western United States. This definition is valuable for interpreting the state of the snowpack for resource management but obscures the temporal evolution of snow drought. Borrowing from dynamical systems theory, we applied phase diagrams to visually examine the evolution of snowpack [...]
Contributions of paleoecology to Easter Island’s prehistory: a thorough review
Published: 2020-07-22
Subjects: Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Life Sciences, Physical Sciences and Mathematics, Plant Sciences, Sustainability
Easter Island (Rapa Nui) is well known for the enigmas surrounding its unique megalithic statues, the moai, and the prehistoric (i.e., pre-European contact) Rapanui society that built them. These enigmas include, among others, the time of the island’s settlement, the geographical origin of the first settlers, the technology associated with moai transportation and emplacement, the occurrence (or [...]
How Extreme Weather Events Are Attributed to Anthropogenic Global Warming
Published: 2020-07-19
Subjects: Environmental Indicators and Impact Assessment, Environmental Sciences, Physical Sciences and Mathematics
Many politicians and media personalities continue to cast doubt on the idea that anthropogenic global warming (AGW) – the primary driver of current global climate change – could possibly be behind the growing frequency and severity of extreme weather events – the droughts, heatwaves, flooding, etc. that are every year breaking 100 year or greater historical records. This takes the form not just [...]
Adopting deep learning methods for airborne RGB fluvial scene classification.
Published: 2020-07-18
Subjects: Environmental Monitoring, Environmental Sciences, Physical Sciences and Mathematics
River environments are among the world’s most threatened ecosystems. Enabled by the rapid development of drone technology, hyperspatial resolution (<10 cm) images of fluvial scenes are now a common data source used to better understand these sensitive habitats. However, the task of image classification remains challenging for this type of imagery and the application of traditional [...]
Sedimentary structures discriminations with hyperspectral imaging on sediment cores
Published: 2020-07-17
Subjects: Analytical Chemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Multivariate Analysis, Optics, Physical Sciences and Mathematics, Physics, Sedimentology, Statistical Models, Statistics and Probability
Hyperspectral imaging (HSI) is a non-destructive high-resolution sensor, which is currently under significant development to analyze geological areas with remote devices or natural samples in a laboratory. In both cases, the hyperspectral image provides several sedimentary structures that need to be separated to temporally and spatially describe the sample. Sediment sequences are composed of [...]
Post-Processing a Conceptual Rainfall-Runoff Model with an LSTM
Published: 2020-07-10
Subjects: Earth Sciences, Environmental Sciences, Hydrology, Physical Sciences and Mathematics
Machine learning is becoming an increasingly important part of streamflow forecasting, but as these models to date lack a physical basis, there is a potential that they may produce values that are not realistic. We tested a simple post-processing strategy that uses the outputs from a calibrated conceptual model (the Sacramento Soil Moisture Accounting Model with Snow-17; SAC-SMA) as inputs into a [...]
Range-based intensity normalization of ALS data over forested areas using a sensor tracking method from multiple returns
Published: 2020-07-10
Subjects: Education, Engineering, Environmental Monitoring, Environmental Sciences, Forest Management, Forest Sciences, Life Sciences, Natural Resources Management and Policy, Other Forestry and Forest Sciences, Physical Sciences and Mathematics
Airborne laser scanning (ALS) point-clouds are used in forest inventory to map properties of the resource. In most cases, only the (x,y,z) coordinates of the point cloud are used to build predictive models of forest structure. Despite being recorded and provided by data suppliers, the intensity values associated with each point are rarely used as an input to such models because raw intensity [...]
Towards local bioeconomy: A stepwise framework for high-resolution spatial quantification of forestry residues
Published: 2020-07-08
Subjects: Education, Engineering, Environmental Monitoring, Environmental Sciences, Life Sciences, Natural Resources and Conservation, Other Environmental Sciences, Physical Sciences and Mathematics, Sustainability
In the ambition of a transition from fossil carbon use, forestry residues are attracting considerable attention as a feedstock for the future bioeconomy. However, there is a limited spatially explicit understanding of their availability. Confronted with limited resources for extensive field measurement campaigns, there are also limited discussions on the best practices towards a harmonized [...]
Fracture mechanics of rate-and-state faults and fluid injection induced slip
Published: 2020-07-08
Subjects: Earth Sciences, Engineering, Environmental Sciences, Geophysics and Seismology, Oil, Gas, and Energy, Physical Sciences and Mathematics, Physics
Propagation of a slip transient on a fault with rate-and-state dependent friction resembles a fracture which near tip region is characterized by large departure of the slip velocity and fault strength from the steady-state sliding. We develop a near tip solution to describe this unsteady dynamics, and obtain the fracture energy Gc, dissipated in overcoming strength-excursion away from [...]
Climate has contrasting direct and indirect effects on armed conflicts
Published: 2020-07-08
Subjects: Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Geography, Human Geography, International and Area Studies, Library and Information Science, Life Sciences, Nature and Society Relations, Physical and Environmental Geography, Physical Sciences and Mathematics, Remote Sensing, Social and Behavioral Sciences, Statistics and Probability
There is an active debate regarding the influence that climate has on the risk of armed conflict, which stems from challenges in assembling unbiased datasets, competing hypotheses on the mechanisms of climate influence, and the difficulty of disentangling direct and indirect climate effects. We use gridded historical non-state conflict records, satellite data, and land surface models in a [...]
Seasonal methane dynamics in high-elevation lakes in the Sierra Nevada California: the role of elevation, temperature, organic matter, and inorganic nutrients
Published: 2020-07-06
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Freshwater lakes are important but poorly constrained sources of methane to the atmosphere due to high, but variable, rates of methane production, as well as limited and inconsistent measurements worldwide. High-elevation lakes have been particularly overlooked—despite their large numbers in mountain ranges around the world, and despite methane dynamics at high elevations may be altered by rapid [...]
Surprising Changes in Aerosol Loading over India Amid COVID-19 Lockdown
Published: 2020-07-06
Subjects: Atmospheric Sciences, Climate, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Using ground-based and satellite observation along with aerosol reanalysis products, we show a widespread reduction in aerosol loading over the Indian subcontinent during the COVID-19 (COronaVIrus Disease 2019) lockdown. The pre-lockdown and lockdown period considered in the present study is 20th February–20th March 2020 and 24th March–22nd April 2020. In terms of aerosol optical depth (AOD), [...]
Deep spatial transformers for autoregressive data-driven forecasting of geophysical turbulence
Published: 2020-07-05
Subjects: Artificial Intelligence and Robotics, Atmospheric Sciences, Climate, Computer Sciences, Dynamical Systems, Earth Sciences, Environmental Sciences, Fluid Dynamics, Geophysics and Seismology, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics
A deep spatial transformer based encoder-decoder model has been developed to autoregressively predict the time evolution of the upper layers stream function of a two-layered quasi-geostrophic (QG) system without any information about the lower layers stream function. The spatio-temporal complexity of QG flow is comparable to the complexity of 500hPa Geopotential Height (Z500) of fully coupled [...]