Simple Earth Research Articles

Climate-denying rumor propagation in a coupled socio-climate model: Impact on average global temperature.

Individual attitudes vastly affect the transformations we are experiencing and are vital in mitigating or intensifying climate change. A socio-climate model by coupling a model of rumor dynamics in heterogeneous networks to a simple Earth System model is developed, in order to analyze how rumors about climate change impact individuals' opinions when they may choose to either believe or reject the rumors they come across over time. Our model assumes that when individuals experience an increase in the global temperature, they tend to not believe the rumors they come across. The rumor rejectors limit their CO2 emissions to reduce global temperature. Our numerical analysis indicates that, over time, the temperature anomaly becomes less affected by the variations in rumor propagation parameters, and having larger groups (having more members) is more efficient in reducing temperature (by efficiently propagating rumors) than having numerous small groups. It is observed that decreasing the number of individual connections does not reduce the size of the rejector population when there are large numbers of messages sent through groups. Mitigation strategies considered by the rejectors are highly influential. The absence of mitigative behavior in rejectors can cause an increase in the global average temperature by 0.5°C. Our model indicates that rumor propagation in groups has the upper hand in controlling temperature change, compared to individual climate-denying propagation.

Radical ligand transfer: a general strategy for radical functionalization.

The place of alkyl radicals in organic chemistry has changed markedly over the last several decades, evolving from challenging-to-generate "uncontrollable" species prone to side reactions to versatile reactive intermediates enabling construction of myriad C-C and C-X bonds. This maturation of free radical chemistry has been enabled by several advances, including the proliferation of efficient radical generation methods, such as hydrogen atom transfer (HAT), alkene addition, and decarboxylation. At least as important has been innovation in radical functionalization methods, including radical-polar crossover (RPC), enabling these intermediates to be engaged in productive and efficient bond-forming steps. However, direct engagement of alkyl radicals remains challenging. Among these functionalization approaches, a bio-inspired mechanistic paradigm known as radical ligand transfer (RLT) has emerged as a particularly promising and versatile means of forming new bonds catalytically to alkyl radicals. This development has been driven by several key features of RLT catalysis, including the ability to form diverse bonds (including C-X, C-N, and C-S), the use of simple earth abundant element catalysts, and the intrinsic compatibility of this approach with varied radical generation methods, including HAT, radical addition, and decarboxylation. Here, we provide an overview of the evolution of RLT catalysis from initial studies to recent advances and provide a conceptual framework we hope will inspire and enable future work using this versatile elementary step.

Least-squares reverse time migration with shifted total variation regularization

Reverse time migration (RTM), as a state-of-the-art imaging technique, provides outstanding imaging capabilities due to its use of a full wave equation. Least-squares RTM (LSRTM) seeks the solution of a linearized wave equation via the minimization of a data misfit term; however, the quality of the results decreases when the assumptions of the method are not satisfied. This occurs, for example, when we use an erroneous velocity model or inadequate physics for inverting the data. In such cases, appropriate regularization is required to mitigate these shortcomings and stabilize the LSRTM solution. However, even for structurally simple earth models, the reflectivity images are complicated and may not be explained properly by particular regularization methods such as the Tikhonov, total variation (TV), or sparse regularization. Reflectivity images can be thought of as the difference between two structurally simpler components: a piecewise-constant component (the true squared slowness) and a smooth component (the background model). We have used a combined Tikhonov-TV regularizer to regularize these components separately, leading to an effective regularization for the reflectivity image. Because the background model is known in advance, this combined regularization reduces to a shifted TV regularization for which the associated optimization problem is solved efficiently using a new implementation of the Bregmanized operator splitting algorithm applied to the shifted TV method and the usual TV method. We determine the performance of our method with a set of numerical examples. The results confirm that our shifted regularization increases the robustness of LSRTM and allows us to estimate high-quality reflectivity images and properly update the background velocity model.

Attitude Determination in Space with Ambient Light Sensors using Machine Learning for Solar Cell Characterization

Exploration of novel thin‐film solar cell technologies outreaches for their application in space. For extraterrestrial tests, irradiance conditions must be well determined to extract quantitative solar cell performances. Here, a new method for solar position determination is presented, based on parallelized ambient light sensor measurements is presented obtained from the sounding rocket experiment Organic and Hybrid Solar Cells In Space during the MAPHEUS‐8 mission. The solar position evolution is optimized using stochastic and gradient‐based methods in a Bayesian approach. Comparison with independent positioning estimates shows compelling agreement, lying mostly within 5° deviation. The inclusion of a simple Earth irradiation component mitigates a small systematic offset. Further, solution uncertainties are estimated with Monte‐Carlo Markov‐chain sampling. The point‐source irradiation model's accuracy can compete with that of a camera‐based trajectory. During equatorial Sun positions, the method's precision appears even higher––the 1σuncertainty of the derived solar position is as small as 3° for the effective angular deviation. This simple sensor array triangulation method being complementary to other attitude determination methods shows reasonable accuracies and allows implementation in systems of limited computational capabilities to determine the solar position or irradiance conditions for space or terrestrial solar cell applications.

Probability of committed warming exceeding 1.5 ∘C and 2.0 ∘C Paris targets

The feasibility of achieving the Paris 1.5 ∘C target continues to be a complex and hotly debated question. To help resolve this question we calculate probability distributions of the committed warming that would ensue if all anthropogenic emissions were stopped immediately, or at successive future times. We use a simple Earth system model together with a Bayesian approach that incorporates multiple lines of evidence and accounts for known model biases. This analysis reveals a wide range of possible outcomes, including no further warming, but also a 15% chance of overshooting the 1.5 ∘C target, and 1%–2% chance for 2 ∘C, even if all emissions had stopped in 2020. If emissions merely stabilize in 2020 and stop in 2040, these probabilities increase to 90% and 17%. The uncertainty arises mainly from that of present forcing by aerosols. Rather than there being a fixed date by which emissions must stop, the probability of reaching either target—which is already below 100%—gradually diminishes with delays in eliminating emissions, by 3%–4% per year for 1.5 ∘C.

Revisiting BCC-SESM parameters sensitivity with BCC-CSM1.1 co2-concentration-driven simulations

Based on the results of the complex climate model BCC-CSM, the Beijing Climate Center Simple Earth System Model (BCC-SESM) was developed for climate system simulations in Integrated Assessment Models (IAMs). The first version of the BCC-SESM model was based on a high-emissions scenario (ESMRCP8.5) and tends to overestimate the temperatures in low and medium emissions scenarios. To address this problem, this study uses three CO2-concentration-driven simulations under different RCP scenarios of complex climate models to evaluate parameters sensitivity and their impacts on projection efficacy. The results show that the new version of the BCC-SESM (denoted as BCC-SESM1.1) model based on a medium-emissions scenario experiment (RCP4.5) is more suitable for temperature projections for various climate scenarios. It can well reproduce the original value of complex climate model. At the same time, it also has high predictive efficacies for medium (RCP4.5) and low (RCP2.6) emissions scenarios, although it tends to underestimate for high emissions scenario (RCP8.5). The sensitivity tests for different RCP scenarios shows that the BCC-SESM1.1 has higher efficacy in projections of future climate change than those model versions based on the other scenarios. The projection deviations for the global average temperature by the BCC-SESM1.1 (<2%) are better than the previous BCC-SESM (<5%). In light of recent progress in climate policy, the BCC-SESM1.1 is hence more suitable for coupling with IAMs for the purposes of assessing climate outcomes.

Necropol Gazigulu – Late Bronze–Early Iron Ages Site of the Khojaly-Gedabey Archaeological Culture in Bassin of Tovuzchay River

Large-scale rescue archaeological excavations were taken during construction of Gazigulu reservoir in western part of Azerbaijan Republic in Tovuz district of Azerbaijan in 2007-2009. Necropolis of the Late Bronze – Early Iron Ages (second part II – beginning I millenniums BC) was studied there. The site belonged to Khojaly-Gedabey archaeological culture. Gazigulu necropolis is situated at the plain, at the left bank of Tovuzchay River (the right inflow of Kura River). In total 18 burials were excavated at Gazigulu necropolis including 16 burials, which were identified as the graves with stone floors mound, another two burials were simple earth graves. The skeletons were buried in crouched / strong crouched position at left or right sides. Archaeological materials mainly,consist from the different types of ceramic vessels, metal wares and adornment. According to the author's definition, the Gazigulu burial rite was identical to the common burial traditions of population of the region during the period under study.

An approach for constraining mantle viscosities through assimilation of palaeo sea level data into a glacial isostatic adjustment model

Abstract. Glacial isostatic adjustment is largely governed by the rheological properties of the Earth's mantle. Large mass redistributions in the ocean–cryosphere system and the subsequent response of the viscoelastic Earth have led to dramatic sea level changes in the past. This process is ongoing, and in order to understand and predict current and future sea level changes, the knowledge of mantle properties such as viscosity is essential. In this study, we present a method to obtain estimates of mantle viscosities by the assimilation of relative sea level rates of change into a viscoelastic model of the lithosphere and mantle. We set up a particle filter with probabilistic resampling. In an identical twin experiment, we show that mantle viscosities can be recovered in a glacial isostatic adjustment model of a simple three-layer Earth structure consisting of an elastic lithosphere and two mantle layers of different viscosity. We investigate the ensemble behaviour on different parameters in the following three set-ups: (1) global observations data set since last glacial maximum with different ensemble initialisations and observation uncertainties, (2) regional observations from Fennoscandia or Laurentide/Greenland only, and (3) limiting the observation period to 10 ka until the present. We show that the recovery is successful in all cases if the target parameter values are properly sampled by the initial ensemble probability distribution. This even includes cases in which the target viscosity values are located far in the tail of the initial ensemble probability distribution. Experiments show that the method is successful if enough near-field observations are available. This makes it work best for a period after substantial deglaciation until the present when the number of sea level indicators is relatively high.

Innovation of simple binoculars as a teaching aid for optical practicum at school

Learning aids are tools used by teachers in learning and prevent verbalization in students. The purpose of this research is to make simple earth telescopes as visual aids for optical practicum in schools. The method used is the experimental method, namely analyzing, designing, making and testing the props made. The subjects of the research were 17 students of physics education FKIP University of Mataram. The binoculars test saw the object of letters and writing with the font Times New Roman 350 at a distance of 50 meters and 100 meters. The results showed that the object was clearly visible with the satisfaction level of using the teaching aids a score of 3.71 the criteria were satisfied and suitable for use. The use of simple earth telescopes is suitable for use in optical practicums in schools. Teachers are expected to be able to create and develop teaching aids to improve students’ understanding of concepts.

Decadal to Centennial Timescale Mantle Viscosity Inferred From Modern Crustal Uplift Rates in Greenland

AbstractThe observed crustal uplift rates in Greenland are caused by the combined response of the solid Earth to both ongoing and past surface mass changes. Existing elastic Earth models and Maxwell linear viscoelastic GIA (glacial isostatic adjustment) models together underpredict the observed uplift rates. These models do not capture the ongoing mantle deformation induced by significant ice melting since the Little Ice Age. Using a simple Earth model within a Bayesian framework, we show that this recent mass loss can explain the data‐model misfits but only when a reduced mantle strength is considered. The inferred viscosity for sub‐centennial timescale mantle deformation is roughly one order of magnitude smaller than the upper mantle viscosity inferred from GIA analysis of geological data. Reconciliation of geological sea‐level and modern crustal motion data may require that the model effective viscosity be treated with greater sophistication than in the simple Maxwell rheological paradigm.

Rotational modes of Poincaré Earth models

ABSTRACT We study the following rotational modes of Poincaré Earth models: the tilt-over mode (TOM), the spin-over mode (SOM) and free core nutation (FCN), using first a simple Earth model with a homogeneous and incompressible liquid core (LC) and a rigid mantle (MT). We obtain analytical solutions for the periods of these modes as well as that of the Chandler wobble (CW). We show analytically the distinction between the TOM and the SOM and that the FCN is indeed the same mode as the SOM of a wobbling Earth. The reduced pressure, in terms of which the vector momentum equation is known to reduce to a scalar second-order partial differential equation called the Poincaré equation, is used as the independent variable. Analytical solutions are then found for the displacement eigenfunctions in a meridional plane of the liquid core for the aforementioned modes. We next consider a three-layer Earth model similar to above which also includes a rigid inner core (IC). We first show that analytical solutions exist for the period and eigenfunctions of the CW if the IC is locked to the MT, i.e. they have the same wobbling motion. We show that this is significant as it shows that the CW manifests itself for a Poincaré (incompressible and inviscid LC) wobbling Earth model. We further allow for the inner core to wobble independently and compute numerically the periods and displacement eigenfunctions of the TOM, SOM and FCN, as well as those for still another rotational mode, the inner-core wobble (ICW). Next we show that the presence of the characteristic surfaces intercepted by the inner-core, when computing the period and eigenfunctions of the free inner-core nutation (FICN), may be the reason for the slow (or lack of the) convergence of this mode. Finally, we show that even though the wobbling motion of the mantle is ignored when solving for the frequencies of the ICW and the FICN when Sasao's approximation is used, the analytical solutions for both these modes yield periods nearly identical to those in the literature for a similar Earth model with mantle allowed to wobble as well. We infer that the Sasao's approximation, or the severe truncation of the series solution of the field variables, the pressure, the gravitational potential and the components of the displacement vector, may not be adequate to accurately describe the motion in the liquid core during the excitation of the FICN.

Global climate damage in 2 °C and 1.5 °C scenarios based on BCC_SESM model in IAM framework

The quantitative functions for climate damages provide theoretical ground for the cost-benefit analysis in climate change economics, and they are also critical for linking climate module with economic module in the Integrated Assessment Models (IAMs). Nevertheless, it is necessary for IAMs to update sectoral climate impacts in order to catch up the advance in climate change studies. This study updates the sectoral climate damage function at global scale from climate Framework for Uncertainty, Negotiation and Distribution (FUND) model and develops the aggregate climate damage function in a bottom-up fashion. Besides conventional sectors such as agriculture, forestry, water resources, energy consumption and ecosystems, this study expands climate disaster types, assesses human health impacts caused by various air pollutants, and updates coastal damage by sea level rise. The Beijing Climate Center Simple Earth System Model (BCC_SESM) is used to project climate system based on Business-as-Usual (BAU) scenario, and the 2 °C and 1.5 °C scenarios based on RCPs and SSP2 databases. Sectoral results show that the agricultural sector is projected to suffer 63% of the total damage, followed by water resources (16%) and human health (12%) sectors in 2100. The regression results indicate that the aggregate climate damage function is in positive quadratic form for zero discounting. Under BAU scenario, the aggregate climate damage is projected to be 517.7 trillion USD during 2011–2100. Compared to that, the 2 °C and 1.5 °C scenarios are projected to respectively reduce climate damages by 215.6 trillion USD (approximately 41.6%) and 263.5 trillion USD (50.9%) in 2011–2100.

Deformation of a spherical, viscoelastic, and incompressible Earth for a point load with periodic time change

SUMMARY Planetary-scale mass redistributions occur on Earth for certain spatiotemporal periods, and these surface mass changes excite the global periodic loading deformations of a viscoelastic Earth. However, the characteristics of periodic viscoelastic deformations have not been well investigated even in a simple earth model. In this study, we derive the semi-analytical Green's functions (fully analytical Love numbers) for long-standing point sources with given periods using a modified asymptotic scheme in a homogeneous Maxwell spherical earth model. Here, the asymptotic scheme is needed in order to obtain accurate semi-analytical time-dependent Green's functions. The amplitudes and phases of the Green's functions may be biased if only the series summations of the Love numbers are used because the influence of viscoelasticity is degree-dependent. We compare the viscoelastic and elastic periodic Green's functions with different material viscosities and loading periods and investigate the amplitude increase percentage and phase delay of the periodic displacement and geoid change. For example, our analysis revealed that the viscosity increases the amplitude by 40–120 per cent and delays the phase approximately −100° to 60° for the displacement and geoid change when bearing a 10-yr loading period, assuming a viscosity of 1018 Pa s and a shear modulus 4 × 1010 Pa.

Retrograde-rotating Exoplanets Experience Obliquity Excitations in an Eccentricity-enabled Resonance

Abstract Previous studies have shown that planets that rotate retrograde (backward with respect to their orbital motion) generally experience less severe obliquity variations than those that rotate prograde (the same direction as their orbital motion). Here, we examine retrograde-rotating planets on eccentric orbits and find a previously unknown secular spin–orbit resonance that can drive significant obliquity variations. This resonance occurs when the frequency of the planet’s rotation axis precession becomes commensurate with an orbital eigenfrequency of the planetary system. The planet’s eccentricity enables a participating orbital frequency through an interaction in which the apsidal precession of the planet’s orbit causes a cyclic nutation of the planet’s orbital angular momentum vector. The resulting orbital frequency follows the relationship , where and are the rates of the planet’s changing longitude of periapsis and longitude of ascending node, respectively. We test this mechanism by simulating cases of a simple Earth–Jupiter system and confirm the predicted resonance. Over the course of 100 Myr, the test Earths with rotation axis precession rates near the predicted resonant frequency experienced pronounced obliquity variations of the order of 10°–30°. These variations can be significant and suggest that while retrograde rotation is a stabilizing influence most of the time, retrograde rotators can experience large obliquity variations if they are on eccentric orbits and enter this spin–orbit resonance.

Steinschlagschutzdämme: Konstruktion und Bemessung

AbstractThe introduction of Austrian standard ONR 24810 provides a design concept for earth dams to protect against massive rockfall events. The essential basis for the concept is the differentiation into five construction types of rockfall embankments due to different system behaviour. The structure therefore has to be assigned to one type at the beginning of the design process. The types available for selection are a simple earth dam (type I), a dam with quarry stone facing (type II), a geosynthetic‐reinforced dam without increased crosswise distribution of the impact loads (type III), a geosynthetic‐reinforced dam with increased crosswise distribution (type IVa) and with strongly increased crosswise distribution (type IVb) of the impact loads. Eurocode 7 (EC 7) is considered accordingly. The design concept is currently being discussed and used in Austria, Switzerland, Germany and Norway. Presented are the design principle and the construction as executive summary.

전산해석을 이용한 흙댐 저수지 붕괴 및 침수지역 분석

Failure of aged reservoir dams is one of the life threatening hazards. When an earth dam fails, the early stage of breached water contains a mixture of solid particles of various sizes and water. Due to high uncertainty in the phenomena of the dam failure and the debris flow of multiphase of water and soil, the dam breach has been studied mainly by shallow water approach of 2D flow for single phase of water. But the actual incidents of the earth dam failure have shown that the mixture of soil and water causes greater damages not only by flooding but also by structural damages due to the impact forces of the debris flow. Based on the previous study showing the potential validity to estimate the debris flow, this study models the failure of the earth dam using computational fluid dynamics of multiphase flow with nonlinear viscosity. First, the collapses of water and soil columns modeling simple earth dam are simulated, which shows the effects of the debris flow on the impact forces. The real collapse of Sandae reservoir is, then, simulated and the flooded region is compared with the previous studies of field survey. The results show some discrepancies due to uncertainties in both field study and the present computations; however, it shows that the breach of the earth dam can be modeled and simulated using the proposed method.

A simple earth system model for C3IAM: based on BCC_CSM1.1 and CMIP5 simulations

Traditional complex climate system models used in natural sciences cannot match the integrated assessment models well due to differences in temporal and spatial resolutions and especially computational complexities. In this study, we develop a simple earth system model called Beijing Climate Center Simple Earth System Model (BCC_SESM), which is based on the complex BCC_CSM1.1 model and its CMIP5 simulation results as inputs. The basic and complete processes are considered in the BCC_SESM initiating from the carbon emission, including the carbon cycle processes in atmosphere–land–ocean, the radiation forcing and temperature changes. The emission-driven simulation results for historical and RCP8.5 scenarios are selected as the default datasets, and econometric regressions are applied to calibrate the parameters. Projection analysis and sensitive experiments with the BCC_SESM show that this model is parsimonious and robust enough to reproduce results of original complex climate system model. We also compare results of parameters and projection efficacy of different mid-lower emission scenarios simulations by applying this BCC_SESM. The results show that BCC_SESM is suitable for climate projections in the integrated assessment modeling, i.e., the C3IAM.

Modeling and assessing the effects of the sea surface, from being flat to being rough and dynamic

The sea surface acts as a very strong reflector because of the large impedance contrast between water and air. The reflection coefficient is [Formula: see text] in a very good approximation. Apart from the surface multiples, the sea surface is also responsible for generating the source and receiver ghost wavefields. These cause the well-known ghost notches in the spectrum: areas where the signal-to-noise ratio is very low. To model the ghost wavefields, ghost operators can be computed and applied to ghost-free data. Modeling experiments indicate that in the case of a flat sea surface, the character of the notches in various gather types, e.g., receiver gather, common-offset gather, shot record, is largely determined by the complexity of the earth. In a simple earth, e.g., horizontally layered, the notches are always well-defined and deep, but in a complex earth, they become blurry in some of the gather types. Therefore, in the case of a complex subsurface, source deghosting is best carried out in the common-receiver domain and receiver deghosting is best carried out in the common-shot domain. In the case of a simple subsurface, deghosting can be carried out in all domains. An additional factor is that the sea surface may be rough and dynamic. This causes blurry ghost notches in all gather types, even in the case of a simple earth. To model the source ghost for this situation, an effective static rough sea surface suffices. This keeps the computations simple. The condition is that the source has an impulsive character. However, to model the receiver ghost (and the source ghost for a nonimpulsive source), the dynamics of the sea surface must be included. This can be done by composing the final result from the results computed for several “frozen” snapshots of the dynamic sea surface.

A New Hybrid Coupled Model of Atmosphere, Ocean Physics, and Ocean Biogeochemistry to Represent Biogeophysical Feedback Effects in the Tropical Pacific

AbstractMultiple processes are involved in modulating the El Niño‐Southern Oscillation (ENSO) in the tropical Pacific, and these processes are neither well‐represented nor well‐understood in climate models. A new hybrid coupled model (HCM) of atmosphere, ocean physics, and ocean biogeochemistry (AOPB) is developed to represent the feedback from ocean biogeochemistry onto ocean physics via modulating the penetration of shortwave radiation in the upper ocean. An ocean biogeochemistry model is coupled with a simplified ocean‐atmosphere system consisting of an ocean general circulation model (OGCM) and a statistical atmospheric model for interannual anomalies of wind stress (τ). The HCM AOPB serves as a simple Earth system for the tropical Pacific to represent the coupling among the atmospheric and physical and biogeochemical ocean components. Model experiments are performed to illustrate this new model's ability to depict the mean ocean state and interannual variability associated with the ENSO. The relationships among anomaly fields are analyzed to illustrate the ocean biogeochemistry‐induced heating feedback and its modulating effects on the ENSO, which is characterized by a negative feedback. The underlying processes and mechanisms are analyzed and can be attributed to dominant modulation of the penetrative solar radiation through the base of the mixed layer (ML). It is demonstrated that the ocean biogeochemistry‐induced negative feedback is mainly driven by more solar radiation penetrating out of the ML during El Nino and less penetrating during La Nina. Further model applications to studies on these processes and biogeochemical‐physical interactions are discussed.

Eigenmode Prediction of the Schumann Resonances

The electromagnetic simulation of the Earth eigenfrequencies is covered, the so-called Schumann resonances. Comparisons to analytical and also measured results are presented, validating the approach. Similar numerical evaluations performed in time domain (finite-difference time-domain) and frequency domain (finite-element method) are also used for comparisons. The eigenmode resonances hereby computed do not need a source of excitation, unlike time-domain codes. A simple Earth model is evaluated (two concentric lossless metallic spheres), as well as one model with a ten-layer atmosphere finite conductivity profile, and also an oblate spheroid geometry. To the knowledge of the author, this is the first reported electromagnetic simulation of the earth Schumann eigenomodes, considering it a closed structure without need for excitation. The eigenmode analysis allows a simple and effective resonance frequency of not only the Earth but also other planets. Comparisons to available experimental data prove the effectiveness of the analysis.