Preprints
There are 6976 Preprints listed.
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), [...]
Bayesian inference for fault slip distributions based on ensemble modeling of the uncertainty of underground structure
Published: 2020-07-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The prediction errors that originate from the uncertainty of underground structure is often a major contributor of the errors between the data and the model predictions in fault slip estimation using geodetic or seismic waveform data. However, most studies on slip inversions either neglect the model prediction errors or do not distinguish them from observation errors. Several methods that [...]
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 [...]
Mass independent fractionation of even and odd mercury isotopes during atmospheric mercury redox reactions
Published: 2020-07-08
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Mass independent fractionation (MIF) of even mass number mercury (Hg) stable isotopes is observed in rainfall and gaseous elemental Hg0 globally, and is used to quantify atmospheric Hg deposition pathways. The chemical reaction and underlying even-Hg MIF mechanism are unknown however, and speculated to be caused by Hg photo-oxidation on aerosols at the tropopause. Here we investigate the Hg [...]
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 [...]
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 [...]
Machine learning and fault rupture: a review
Published: 2020-07-02
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Geophysics and Seismology, Mathematics, Physical Sciences and Mathematics, Theory and Algorithms
Geophysics has historically been a data-driven field, however in recent years the exponential increase of available data has lead to increased adoption of machine learning techniques and algorithm for analysis, detection and forecasting applications to faulting. This work reviews recent advances in the application of machine learning in the study of fault rupture ranging from the laboratory to [...]
GANSim: Conditional Facies Simulation Using an Improved Progressive Growing of Generative Adversarial Networks (GANs)
Published: 2020-07-05
Subjects: Artificial Intelligence and Robotics, Computer Sciences, Earth Sciences, Geology, Hydrology, Mathematics, Physical Sciences and Mathematics, Sedimentology, Statistical Models, Statistics and Probability
Conditional facies modeling combines geological spatial patterns with different types of observed data, to build earth models for predictions of subsurface resources. Recently, researchers have used generative adversarial networks (GANs) for conditional facies modeling, where an unconditional GAN is first trained to learn the geological patterns using the original GANs loss function, then [...]
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 [...]
Exposure and vulnerability estimation for modelling flood losses to commercial assets in Europe
Published: 2020-07-05
Subjects: Earth Sciences, Hydrology, Multivariate Analysis, Physical Sciences and Mathematics, Statistics and Probability
Commercial assets comprise buildings, machinery and equipment, which are susceptible to floods. Existing damage models and exposure estimation methods for this sector have limited transferability between flood events. In this study we introduce two methodologies aiming at broader applicability: (1) disaggregation of economic statistics to obtain detailed building-level estimates of replacement [...]
Pumped Storage Hydropower: A Grid Intermittency Solution
Published: 2022-08-30
Subjects: Environmental Studies
As public pressure and state emissions targets increasingly promote grid decarbonization, society must find solutions to the intermittency problem of renewable energy. While several emerging battery technologies provide a solution to this problem, pumped storage hydropower (PSH) is the most promising given its long lifecycle and widespread deployment. This paper will analyze and compare PSH with [...]
Post-processing the National Water Model with Long Short- Term Memory Networks for Streamflow Predictions and Model Diagnostics
Published: 2020-07-02
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
We build three Long Short-Term Memory (LSTM) daily streamflow prediction models (deep learning networks) for 531 basins across the contiguous United States (CONUS), and compare their performance: (1) a LSTM post-processor trained on the U.S. National Water Model (NWM) outputs (LSTM_PP) as a target variable, (2) a LSTM post-processor trained on the NWM outputs and using atmospheric forcings [...]
Ekman-Inertial Instability
Published: 2020-07-05
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
We report on an instability, arising in sub-surface, laterally-sheared flows in rotation. When the lateral shear of a horizontal flow in geostrophic balance is of opposite sign as the Coriolis parameter, and exceeds it in magnitude, embedded perturbations are subjected to inertial instability, albeit modified by viscosity. When the perturbation arises from the surface of the fluid, the initial [...]
Influences on Discharge Partitioning on a Large River Delta: Case Study of the Mississippi-Atchafalaya Diversion, 1926–1950
Published: 2020-07-01
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
The modern Mississippi River (M.R.) Delta is plumbed by the Mississippi and Atchafalaya rivers, setting water and sediment dispersal pathways for Earth’s fifth-largest river system. The Atchafalaya River’s (A.R.) partial annexation of discharge from the M.R., particularly between 1926 and 1950, prompted warnings of a rapid river avulsion and the construction of the Old River Control Structure to [...]