julilili42/papers huggingface dataset:
Plume-induced sinking of the intracontinental lithosphereas a fundamentally new mechanism of subduction initiation.
2022-03-27

&amp;lt;p&amp;gt;Although many different mechanisms for subduction initiation have been proposed, few of them are viable in terms of agreement with observations and reproducibility in numerical experiments. In particular, it has recently been demonstrated that intra-oceanic subduction triggered by an upwelling mantle plume could contribute greatly to the onset and functioning of plate tectonics in the early Earth and, to a lesser extent, in the modern Earth. In contrast, the onset of intracontinental subduction is still underestimated. Here we review 1) observations demonstrating the upwelling of hot mantle material flanked by sinking proto-slabs of the continental mantle lithosphere, and 2) previously published and new numerical models of plume-induced subduction initiation. Numerical modelling shows that under the condition of a sufficiently thick (&amp;gt; 100 km) continental plate, incipient down thrusting at the level of the lowermost lithospheric mantle can be triggered by plume anomalies with moderate temperatures and without significant strain and/or melt-induced weakening of the overlying rocks. This finding is in contrast to the requirements for plume-induced subduction initiation in oceanic or thin continental lithosphere. Consequently, plume-lithosphere interactions in the continental interior of Paleozoic-Proterozoic (Archean) platforms are the least demanding (and therefore potentially very common) mechanism for triggering subduction-like foundering in Phanerozoic Earth. Our findings are supported by a growing body of new geophysical data collected in a variety of intracontinental settings. A better understanding of the role of intracontinental mantle downthrusting and foundering in global plate tectonics and, in particular, in triggering &amp;quot;classic&amp;quot; oceanic-continental subduction will benefit from further detailed follow-up studies.&amp;lt;/p&amp;gt;
Unraveling archaeological settlement, landscape, and resource use patterns with machine learning in Kurdistan (Iraq)
2022-03-27

&amp;lt;p&amp;gt;&amp;amp;#160;&amp;amp;#160;&amp;amp;#160;&amp;amp;#160;&amp;amp;#160;&amp;amp;#160; The traditional view on Mesopotamian resources strategies is understood as &amp;amp;#8220;resource hunting&amp;amp;#8221; in which Mesopotamian empires would have spread to neighbouring regions (Zagros, Taurus, Levant&amp;amp;#8230;) to monopolize their resources. Indeed, Mesopotamia lacks some resources/raw materials such as copper, iron, wood, obsidian, and others. Our &amp;lt;em&amp;gt;RessourceCultures&amp;amp;#160;&amp;lt;/em&amp;gt;approach&amp;lt;em&amp;gt;,&amp;amp;#160;&amp;lt;/em&amp;gt;developed in SFB 1070, aims to define resources in a wider spectrum, to propose new interpretations on cultures development in this region. By investigating new patterns rules of resources appropriation and uses in peripheral areas, we hope to bring interesting new results. Our survey covered an area of 4.400 km&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; from the western foothills of the Zagros mountains to the eastern riverbank of the Tigris.&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;amp;#160; &amp;amp;#160; &amp;amp;#160;&amp;amp;#160;To unravel the patterns that define a&amp;amp;#160;&amp;lt;em&amp;gt;ResourceCulture&amp;lt;/em&amp;gt;&amp;amp;#160;we combine both archaeological and geoarchaeological data into a machine learning approach. Many features (topography, water, soil type, resources availability, climate&amp;amp;#8230;) influence the founding and location of settlements in different ways and degrees of importance. The trend of these influences can be analyzed through machine learning models in predictive archaeology. Letting the machine run predictive models and underline the relationship between each feature and settlement dynamic will potentially help us to better understand how resources were used in a cultural and economic context through time and space.&amp;amp;#160; &amp;amp;#160; &amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;amp;#160; &amp;amp;#160; &amp;amp;#160; &amp;amp;#160; &amp;amp;#160; &amp;amp;#160;Our poster will present the first ideas derived from the machine learning approach: Is there any trends appearing and what can we say from them? Can we redefine the&amp;amp;#160;&amp;lt;em&amp;gt;ResourceCulture&amp;amp;#160;&amp;lt;/em&amp;gt;in Northern Mesopotamia through these new interpretations?&amp;amp;#160;&amp;lt;/p&amp;gt;
Elucidating soil pore N2O production and consumption processes using isotope and microbial gene analysis: A depth profile approach
2022-03-27

&amp;lt;p&amp;gt;N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O is a stratospheric ozone depleting substance and a potent greenhouse gas which significantly contributes to global warming. Although soils are the largest source of N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O emissions, knowledge gaps in the understanding of N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O production and reduction processes in soils still exist. Here, we investigated N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O production and consumption processes along soil depth profiles in a mesocosm experiment using natural-abundance N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O and NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;-&amp;lt;/sup&amp;gt; isotopic signatures as well as abundances of soil microbial genes associated with N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O production (&amp;lt;em&amp;gt;nirK, nirS&amp;lt;/em&amp;gt;) and reduction (&amp;lt;em&amp;gt;nosZ&amp;lt;/em&amp;gt;). Soil columns either displayed undisturbed soil stratification (control treatments), or contained an artificial clay layer at 35 cm depth (clay treatment), which acted as a diffusion barrier and thus induced O&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-limited conditions in deeper strata. We collected soil pore gas, soil solution and soil samples at five depths of the soil columns over the course of four weeks. In addition, we continuously monitored N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O fluxes at the soil surface and soil environmental parameters (oxygen, moisture, temperature) along the soil depth profiles. Microbial gene analysis in soil samples revealed similar abundances of &amp;lt;em&amp;gt;nirK&amp;lt;/em&amp;gt;, &amp;lt;em&amp;gt;nirS&amp;lt;/em&amp;gt; and &amp;lt;em&amp;gt;nosZ&amp;lt;/em&amp;gt; in the two treatments across the entire soil depth profiles. The distribution of the functional genes was thus not indicative of enhanced N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O production and/or reduction in O&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;-limited conditions. However, lowest O&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; concentrations below the clay layer were associated with highest &amp;lt;sup&amp;gt;15&amp;lt;/sup&amp;gt;N and &amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O enrichments in both NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;-&amp;lt;/sup&amp;gt; and N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O, indicating N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O production by denitrification and fractional N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O reduction.&amp;lt;em&amp;gt; &amp;lt;/em&amp;gt;In addition, we found higher N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O concentrations and surface fluxes for the clay treatment. Our observations imply a dominance of N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O production over N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O reduction, even under conditions most favorable for complete denitrification.&amp;lt;/p&amp;gt;
Identifying patterns of teleconnections, a curvature-based network analysis
2022-03-27

&amp;lt;p&amp;gt;Representing spatio-temporal climate variables as complex networks allows uncovering nontrivial structure in the data. Although various tools for detecting communities in climate networks have been used to group nodes (spatial locations) with similar climatic conditions, we are often interested in identifying important links between communities. Of particular interest are methods to detect teleconnections, i.e. links over large spatial distances mitigated by atmospheric processes.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;We propose to use a recently developed network measure based on Ricci-curvature to visualize teleconnections in climate networks. Ricci-curvature allows to distinguish between- and within-community links in networks. Applied to networks constructed from surface temperature anomalies we show that Ricci-curvature separates spatial scales. We use Ricci-curvature to study differences in global teleconnection patterns of different types of El Ni&amp;amp;#241;o events, namely the Eastern Pacific (EP) and Central Pacific (CP) types. Our method reveals a global picture of teleconnection patterns, showing confinement of teleconnections to the tropics under EP conditions but showing teleconnections to the tropics, Northern and Southern Hemisphere under CP conditions. The obtained teleconnections corroborate previously reported impacts of EP and CP.&amp;lt;br&amp;gt;Our results suggest that Ricci-curvature is a promising visual-analytics-tool to study the topology of climate systems with potential applications across observational and model data.&amp;lt;/p&amp;gt;
State-dependent effects of natural forcing on global and local climate variability&#160;
2022-03-27

&amp;lt;div&amp;gt; &amp;lt;p&amp;gt;Climate variability is the primary influence on climate extremes and affected by natural forcing from solar irradiance and volcanic eruptions. Global warming impacts climate variability, but there is contradictory and incomplete evidence on the spatio-temporal patterns. Strong volcanic eruptions have been suggested to reduce temperatures less in warmer climate states. However, the underlying question of state-dependent effect of natural forcing on local and global variability remains open. Moreover, there are uncertainties about the role of natural forcing in the mismatch between simulated and reconstructed local, long-term variability.&amp;amp;#160;&amp;lt;span&amp;gt;&amp;amp;#160;&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt; &amp;lt;/div&amp;gt;&amp;lt;div&amp;gt; &amp;lt;p&amp;gt;Using a 12-member GCM ensemble with targeted boundary conditions, we present naturally-forced and equilibrium, millennium-length simulations for the Last Glacial Maximum (LGM) and the Pre-Industrial (PI). We quantify the local and global climate response to solar and volcanic forcing in the LGM and PI, and contrast variability from forced and control simulations on annual-to-multicentennial scales. We differentiate various contributions from the atmosphere, oceans, and particularly that of sea ice using a 2D energy balance model (EBM). Spectral analysis of simulated temperatures shows that global variability is predominately determined by natural forcing. Local mean spectra are more characteristic for the mean climate state and reveal a decrease in local variability with warming. The global and local response to natural forcing is robust against changes in the mean climate. Particularly, the spatial patterns of the surface climate's response to volcanic eruptions widely agree across states. Weak local differences resulted primarily from sea ice dynamics. The sea ice contribution is the strongest on interannual scales. It remains significant on decadal scales and longer, providing a key mechanism of long-term variability. We validate the simulated variability against observational and paleoclimate data. The variance obtained from proxies is increasingly larger on longer timescales compared to that from simulated time series. The inclusion of natural forcing reduces the model-data mismatch on decadal-to-multicentennial scales and, thus, provides a more accurate representation of climate variability.&amp;amp;#160;&amp;lt;/p&amp;gt; &amp;lt;/div&amp;gt;&amp;lt;div&amp;gt; &amp;lt;p&amp;gt;Consideration of natural forcing is therefore paramount for model-data comparison and future projections. The robust temperature response suggests that findings on the ability of models to simulate past variability should translate to future climates, and can thus help constrain variability.&amp;lt;span&amp;gt;&amp;amp;#160;&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt; &amp;lt;/div&amp;gt;
Towards spatio-temporal comparison of transient simulations and temperature reconstructions for the last deglaciation
2022-03-27

&amp;lt;p&amp;gt;An increasing number of Earth System Models has been used to simulate the climatic transition from the Last Glacial Maximum to the Holocene. This creates a demand for benchmarking against environmental proxy records, which have been synthesized for the same time period. Comparing these two data sources in space and time over a period with changing background conditions requires new methods. We employ proxy system modeling for probabilistic quantification of the deviation between temperature reconstructions and transient simulations. Regional and global scores quantify the mismatch in the pattern and magnitude of orbital- as well as millennial-scale temperature variations.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In pseudo-proxy experiments, we test the ability of our algorithm to accurately rank an ensemble of simulations according to their deviation from a prescribed temperature history, dependent upon the amount of added non-climatic noise. To this purpose, noisy pseudo-proxies are constructed by perturbing a reference simulation. We show that the algorithm detects the main features separating the ensemble members. When scores are aggregated spatially, the algorithm ranks simulations robustly and accurately in the presence of uncertainties. In contrast, erroneous rankings occur more often if only a single location is assessed.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Having established the effectiveness of the algorithm in idealized experiments, we apply our method to quantify the deviation between data from the PalMod project: an ensemble of transient deglacial simulations and a global compilation of sea surface temperature reconstructions. No simulation performs consistently well across different regions and components of the temperature evolution which we attribute to the larger spatial heterogeneity in reconstructions. Our work provides a basis for a standardized model-data comparison workflow, which can be extended subsequently with additional proxy data, new simulations, and improved representations of uncertainties.&amp;lt;/p&amp;gt;
Investigating &#948;13C values in stalagmites from tropical South America
2022-03-27

&amp;lt;p&amp;gt;Multiple factors control &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C values in speleothems and complicate their paleoclimatic and paleoenvironmental interpretation. Therefore, most studies avoid the presentation of &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C values, and instead, focus only on &amp;amp;#948;&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O. This development can be observed with regard to most recent cave studies from tropical South America, in which stalagmite &amp;amp;#948;&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O were preferentially published without the consideration of &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C data. Here we present a large &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C dataset of 98 speleothem records covering multiple time scales from South America, of which 42 remained unpublished or were not available until now. Our main objective is concentrating on the support of existing and emerging databases, such as SISAL, and providing new data for the speleothem community and climate modelling.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;As a first approach, we review the &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C values for the last two millennia and evaluate the environmental influencing factors on this proxy, e.g., local hydroclimate, altitude, temperature, and abundant vegetation types. Our results indicate that the main factors controlling variations in &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C values are due to changes in the local hydroclimate and, to a minor extent, in temperature. For this time period, most of the isotope records show a significant correlation between the &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C and &amp;amp;#948;&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O values, indicating a close relationship between local hydroclimate and large-scale atmospheric processes related to shifts of the South American Monsoon System (SAMS). Furthermore, in most of the karst systems studied here, the predominant occurrence of C3 plants growing on soils above the caves is responsible for a considerable lowering of &amp;amp;#948;&amp;lt;sup&amp;gt;13&amp;lt;/sup&amp;gt;C values (&amp;amp;#8804;6&amp;amp;#8240;) in most of the speleothems.&amp;lt;/p&amp;gt;
Characterising simulated changes of jet streams since the Last Glacial Maximum
2022-03-27

&amp;lt;p&amp;gt;Jet streams control hydroclimate variability in the mid-latitudes with important impacts on water availability and human societies. According to future projections, global warming will change jet stream characteristics, including its mean position. Variability of these characteristics on hourly-to-daily timescales is key to understanding the mid-latitudes circulation. Therefore, most analysis methods of present-day jet streams are designed for 6-hourly data. By modelling the climate since the Last Glacial Maximum, we can investigate the long-term drivers of jet stream characteristics. However, for transient simulations of the last deglaciation, 3d wind fields are only archived with a monthly resolution due to storage limitations. Hence, jet variability at shorter timescales cannot be identified, and established methods can&amp;amp;#8217;t be used.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Here, we study to what extent changes of jet stream characteristics can be inferred from monthly wind fields. Therefore, we compare latitudinal jet stream positions, strength, tilt and their variability from daily and monthly wind fields in reanalysis data and for LGM and PI simulations. We test three different methods to construct jet stream typologies and metrics. This comparison identifies to which extend these jet stream characteristics can be robustly studied from monthly wind fields. In addition, our analysis assesses the added value of archived daily data for future research. Once the limitations of monthly wind output are known, jet stream characteristics in transient simulations of the last deglaciation can be analysed. This analysis provides new insights on jet stream changes on decadal-to-orbital timescales and identifies the factors controlling these changes.&amp;lt;/p&amp;gt;
Effects of burrowing animals on soil erosion for Chile derived with a fully parameterized erosion model based on in-situ measurements, remote sensing and machine learning
2022-03-27

&amp;lt;p&amp;gt;To date, hillslope-wide effects of burrowing animals on soil erosion, infiltration, surface runoff, water storage and field capacity are hardly understood. Consequently, the effects of burrowing animals are not yet included in erosion models. A suitable approach considering their impacts in erosion models is lacking but needed in order to fully understand the feedbacks between biosphere and sediment fluxes.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;For this presentation, we combined in-situ measurements, high resolution remote sensing data and machine-learning methods with a Daily based Morgan-Morgan-Finney soil erosion model for hillslopes along a climate gradient from arid to humid Chile. To parameterize the erosion model, we trained random forest models to upscale in-situ measured soil properties and the presence of animal burrows to each catchment using high-resolution WorldView-2 data. We conducted a land cover classification to provide the vegetation cover. ith this data, we parametrised one model per climate zone. The model was validated using in-situ installed sediment traps. Model experiments in- and excluding animal burrows were conducted to determine the daily and yearly impacts of burrowing animals on soil erosion, infiltration, surface runoff, subsurface runoff, water storage and field capacity on the burrow and hillslope scale at 0.5 m grid resolution.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The presence of burrows increased sediment erosion, infiltration and water storage and decreased surface runoff and field capacity. The effects were most pronounced on the daily and burrow scale in the semi-arid and mediterranean climate zone. In the semi-arid climate zone, the burrows heavily increased surface infiltration and subsurface runoff. In the mediterranean climate zone, the distribution of burrows had an impact on the surface runoff and increased the erosion rate in the adjusting areas without burrows. In the arid zone, the impact of burrowing animals was solely detectable during sporadically occurring heavy rains.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Our study presents, to our knowledge, for the first time a soil erosion model which includes burrowing animal activity. The results clearly underpin the general importance to consider burrowing animals in erosion modelling.&amp;lt;/p&amp;gt;
Glacio-chemical signature of grain boundaries and insoluble particle aggregates in ice core 2D impurity imaging
2022-03-27

&amp;lt;p&amp;gt;Identifying, understanding, and constraining post-depositional processes altering the original layer sequence in ice cores is especially needed in order to avoid misinterpretation of the oldest and most highly thinned layers. The record of soluble and insoluble impurities represents an important part of the paleoclimate proxy set in ice cores but is known to be affected post-depositionally through interaction with the ice matrix, diffusion and chemical reactions. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been recognized for its micron-scale resolution and micro-destructiveness in ice core impurity analysis. Important added value comes from employing LA-ICP-MS for state-of-the-art 2D chemical imaging. The latter has already revealed a close relationship between the ice grain boundary network and impurity signals with a significant soluble component, such as Na. Here we show the latest improvements in 2D chemical imaging of ice with LA-ICP-MS, by increasing the spatial resolution from 35 to 20 and even 10 &amp;amp;#181;m and extending the simultaneous analysis to cover also mostly insoluble impurity species, such as Al. The latter reveal clear signals of insoluble particle aggregates in samples of Greenland ice cores. Combining the chemical images with computer vision-based image analysis allows to separate the geochemical signals of grain boundaries and insoluble particles. Considering intensities as well as elemental ratios, this classification further highlights important differences in the geochemical signals depending on the location of the impurities in the ice matrix. Ultimately, we discuss how this refined approach may serve to investigate post-depositional changes occurring with increasing depth to the soluble and insoluble impurity components, based on grain growth and chemical reactions, respectively.&amp;lt;/p&amp;gt;