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    Effect of iron and nanolites on Raman spectra of volcanic glasses: A reassessment of existing strategies to estimate the water content 

    Di Genova, Danilo; Sicola, Stefania; Romano, Claudia; Vona, Alessandro; Fanara, Sara; Spina, Laura
    Chemical Geology 2017; 475 p.76-86
    The effect of iron content and iron nanolites on Raman spectra of hydrous geologically-relevant glasses is presented. Current procedures to estimate the water content using Raman spectra were tested to explore potential effects of iron content, its oxidation state, and nanolites on models' reliability. A chemical interval spanning from basalt to rhyolite, including alkali- and iron-rich compositions, with water content up to 5.6 wt% was investigated using two spectrometers. When considering nanolite-free samples, the area of the band at 3550 cm−1 linearly correlates with the sample water content regardless of chemical composition. Using this approach, data were reproduced with a root-mean-square error (RMSE) of ~ 0.15 wt%. Depending on the sample chemistry, water content, and acquisition conditions the laser-induced sample oxidation led to underestimating the water content up to ~ 90% with a long acquisition time (26 min). Normalising the water band region to the silicate band region minimises such a limitation. The area ratio between these bands linearly correlates with the water content and the use of different baseline procedures does not remove the dependence of such a correlation by the iron content and its oxidation state. With this procedure, data were reproduced with a RMSE of ~ 0.16 wt%. For both approaches, the presence of iron nanolites may result in underestimating the water content.
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    Exhumation history and landscape evolution of the Sierra de San Luis (Sierras Pampeanas, Argentina) - new insights from low - temperature thermochronological data 

    Bense, Frithjof; Costa, Carlos; Oriolo, Sebastián; Löbens, Stefan; Dunkl, Istvan; Wemmer, Klaus; Siegesmund, Siegfried
    Andean Geology 2017; 44(3)
    This paper presents low-temperature thermochronological data and K‑Ar fault gouge ages from the Sierra de San Luis in the Eastern Sierras Pampeanas in order to constrain its low-temperature thermal evolution and exhumation history. Thermal modelling based on (U-Th)/He dating of apatite and zircon and apatite fission track dating point to the Middle Permian and the Triassic/Early Jurassic as main cooling/exhumation phases, equivalent to ca. 40-50% of the total exhumation recorded by the applied methods. Cooling rates are generally low to moderate, varying between 2-10 °C/Ma during the Permian and Triassic periods and 0.5-1.5 °C/Ma in post-Triassic times. Slow cooling and, thus, persistent residence of samples in partial retention/partial annealing temperature conditions strongly influenced obtained ages. Thermochronological data indicate no significant exhumation after Cretaceous times, suggesting that sampled rocks were already at or near surface by the Cretaceous or even before. As consequence, Cenozoic cooling rates are low, generally between 0.2-0.5 °C/Ma which is, depending on geothermal gradient used for calculation, equivalent to a total Cenozoic exhumation of 0.6-1.8 km. K-Ar fault gouge data reveal long-term brittle fault activity. Fault gouge ages constrain the end of ductile and onset of brittle deformation in the Sierra de San Luis to the Late Carboniferous/Early Permian. Youngest K-Ar illite ages of 222-172 Ma are interpreted to represent the last illite formation event, although fault activity is recorded up to the Holocene.
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    Quantitative assessment of carbon sequestration reduction induced by disturbances in temperate Eurasian steppe 

    Chen, Yizhao; Ju, Weimin; Groisman, Pavel; Li, Jianlong; Propastin, Pavel; Xu, Xia; Zhou, Wei; Ruan, Honghua
    Environmental Research Letters 2017; 12(11): Art. 115005
    The temperate Eurasian steppe (TES) is a region where various environmental, social, and economic stresses converge. Multiple types of disturbance exist widely across the landscape, and heavily influence carbon cycling in this region. However, a current quantitative assessment of the impact of disturbances on carbon sequestration is largely lacking. In this study, we combined the boreal ecosystem productivity simulator (BEPS), the Shiyomi grazing model, and the global fire model (Glob-FIRM) to investigate the impact of the two major types of disturbance in the TES (i.e. domestic grazing and fire) on regional carbon sequestration. Model performance was validated using satellite data and field observations. Model outputs indicate that disturbance has a significant impact on carbon sequestration at a regional scale. The annual total carbon lost due to disturbances was 7.8 TgCyr−1, accounting for 14.2% of the total net ecosystem productivity (NEP). Domestic grazing plays the dominant role in terrestrial carbon consumption, accounting for 95% of the total carbon lost from the two disturbances. Carbon losses from both disturbances significantly increased from 1999 to 2008 (R2=0.82, P < 0.001 for grazing, R2=0.51, P<0.05 for fire). Heavy domestic grazing in relatively barren grasslands substantially reduced carbon sequestration, particularly in the grasslands of Turkmenistan, Uzbekistan, and the far southwest of Inner Mongolia. This spatially-explicit information has potential implications for sustainable management of carbon sequestration in the vast grassland ecosystems.
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    Trachyte weathering in the urban built environment related to air quality 

    Germinario, Luigi; Siegesmund, Siegfried; Maritan, Lara; Simon, Klaus; Mazzoli, Claudio
    Heritage Science 2017; 5(1): Art. 44
    Decay of trachyte used as building stone in urban environment was investigated through the analysis of crusts and patinas found on trachyte of the Euganean Hills in the Renaissance city walls of Padua, northeastern Italy. Mineralogical and microstructural characteristics of the alteration products, as well as major- and trace-element chemical composition, were determined by optical microscopy, SEM–EDS and X-ray mapping, XRPD, and LA-ICPMS. The results are discussed referring to environmental parameters, in particular concerning air quality and anthropic pollution sources. The influence of composition of the stone and other neighboring materials on specific weathering processes is also debated. The formation of crusts and patinas turns out to be mainly due to exogenous processes. Enrichment in heavy metals and carbonaceous matter derives from the deposition of particulate emitted during fuel combustion by road vehicles, domestic heating and, secondarily, industrial activities. The particulate is typically cemented by calcite, mainly mobilized after dissolution from nearby mortar joints, or iron, released by leaching from iron-bearing minerals, reprecipitated according to pH fluctuations. Gypsum layers were rarely observed. Generally, composition of the weathering crusts and patinas of Euganean trachyte proves to be an informative marker for the relevant environmental conditions and their evolution.
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    Fast methane diffusion at the interface of two clathrate structures. 

    Ranieri, Umbertoluca; Koza, Michael Marek; Kuhs, Werner F.; Klotz, Stefan; Falenty, Andrzej; Gillet, Philippe; Bove, Livia E.
    Nature communications 2017-10-20; 8(1): Art. 1076
    Methane hydrates naturally form on Earth and in the interiors of some icy bodies of the Universe, and are also expected to play a paramount role in future energy and environmental technologies. Here we report experimental observation of an extremely fast methane diffusion at the interface of the two most common clathrate hydrate structures, namely clathrate structures I and II. Methane translational diffusion-measured by quasielastic neutron scattering at 0.8 GPa-is faster than that expected in pure supercritical methane at comparable pressure and temperature. This phenomenon could be an effect of strong confinement or of methane aggregation in the form of micro-nanobubbles at the interface of the two structures. Our results could have implications for understanding the replacement kinetics during sI-sII conversion in gas exchange experiments and for establishing the methane mobility in methane hydrates embedded in the cryosphere of large icy bodies in the Universe.
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    A fossil species of the enigmatic early polypod fern genus Cystodium (Cystodiaceae) in Cretaceous amber from Myanmar. 

    Regalado, Ledis; Schmidt, Alexander R.; Appelhans, Marc S.; Ilsemann, Bork; Schneider, Harald; Krings, Michael; Heinrichs, Jochen
    Scientific reports 2017-11-06; 7(1): Art. 14615
    The monospecific fern genus Cystodium (Cystodiaceae; Polypodiales) occurs exclusively in the tropical forests of the Malay Archipelago, the Admiralty Islands, the Louisiade Archipelago, and the Solomon Islands. Divergence time estimates suggest that the genus originated in the Mesozoic; however, fossil evidence to validate this suggestion has been lacking. Amber from Myanmar (Burmese amber) is an important source of new information on the diversity of vascular cryptogams in the Cretaceous. This paper describes the fossil taxon Cystodium sorbifolioides nov. sp. based on a fragment of a fertile leaf preserved in Burmese amber that represents the first fossil evidence of the family Cystodiaceae. Cystodium sorbifolioides is used to obtain a minimum age estimate for the Cystodiaceae and the closely related, monogeneric Lonchitidaceae and Lindsaeaceae. The fossil strengthens the hypothesis that the forest ecosystems of Malesia and Melanesia represent refugia for many tropical plant lineages that originated in the Cretaceous.
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    Sustainability impact assessment of peatland-use scenarios: Confronting land use supply with demand 

    Hermanns, Till; Helming, Katharina; König, Hannes J.; Schmidt, Katharina; Li, Qirui; Faust, Heiko
    Ecosystem Services 2017; 26 p.365-376
    Sustainable development of land use is determined by changes of the regional supply of Land Use Functions (LUFs) and the demand of future societal land use claims. LUFs are based on the ecosystem services concept, but more adapted to human land use. In this paper, we assessed two peatland-use scenarios towards sustainable development in Northeast Germany in order to understand their impacts on LUFs and land use claims. For this, we extended an analytical framework designed to confront LUFs with land use claims identified in multi-level stakeholder strategies in a participatory manner. The sustainability assessment was performed with peatlanduse scenarios “Services for services” and “Market determines usage” that favoured environmental and economic land use claims, respectively. Findings revealed possible trade-offs between land use claims for biomass production and regional value creation as well as for peatlands` carbon and nutrient sink, and habitat functions. The core achievement is an extended sustainability assessment framework integrating land use demands of multi-level stakeholder strategies into participatory impact assessment, in a way that land use claims serve as benchmarks for LUFs. This facilitates the understanding of sustainable land use in both supply and demand perspective, and the normative evaluation of ecosystem services.
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    Contemporaneous assembly of Western Gondwana and final Rodinia break-up: Implications for the supercontinent cycle 

    Oriolo, Sebastián; Oyhantçabal, Pedro; Wemmer, Klaus; Siegesmund, Siegfried
    Geoscience Frontiers 2017; 8(6) p.1431-1445
    Geological, geochronological and isotopic data are integrated in order to present a revised model for the Neoproterozoic evolution of Western Gondwana. Although the classical geodynamic scenario assumed for the period 800e700 Ma is related to Rodinia break-up and the consequent opening of major oceanic basins, a significantly different tectonic evolution can be inferred for most Western Gondwana cratons. These cratons occupied a marginal position in the southern hemisphere with respect to Rodinia and recorded subduction with back-arc extension, island arc development and limited formation of oceanic crust in internal oceans. This period was thus characterized by increased crustal growth in Western Gondwana, resulting from addition of juvenile continental crust along convergent margins. In contrast, crustal reworking and metacratonization were dominant during the subsequent assembly of Gondwana. The Río de la Plata, Congo-São Francisco, West African and Amazonian cratons collided at ca. 630 e600 Ma along the West Gondwana Orogen. These events overlap in time with the onset of the opening of the Iapetus Ocean at ca. 610e600 Ma, which gave rise to the separation of Baltica, Laurentia and Amazonia and resulted from the final Rodinia break-up. The East African/Antarctic Orogen recorded the subsequent amalgamation of Western and Eastern Gondwana after ca. 580 Ma, contemporaneously with the beginning of subduction in the Terra Australis Orogen along the southern Gondwana margin. However, the Kalahari Craton was lately incorporated during the Late EdiacaraneEarly Cambrian. The proposed Gondwana evolution rules out the existence of Pannotia, as the final Gondwana amalgamation postdates latest connections between Laurentia and Amazonia. Additionally, a combination of introversion and extroversion is proposed for the assembly of Gondwana. The contemporaneous record of final Rodinia break-up and Gondwana assembly has major implications for the supercontinent cycle, as supercontinent amalgamation and break-up do not necessarily represent alternating episodic processes but overlap in time.
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    Relict high-Andean ecosystems challenge our concepts of naturalness and human impact 

    Sylvester, Steven P.; Heitkamp, Felix; Sylvester, Mitsy D. P. V.; Jungkunst, Hermann F.; Sipman, Harrie J. M.; Toivonen, Johanna M.; Gonzales Inca, Carlos A.; Ospina, Juan C.; Kessler, Michael
    Scientific Reports 2017; 7(1): Art. 3334
    What would current ecosystems be like without the impact of mankind? This question, which is critical for ecosystem management, has long remained unanswered due to a lack of present-day data from truly undisturbed ecosystems. Using mountaineering techniques, we accessed pristine relict ecosystems in the Peruvian Andes to provide this baseline data and compared it with the surrounding accessible and disturbed landscape. We show that natural ecosystems and human impact in the high Andes are radically different from preconceived ideas. Vegetation of these ‘lost worlds’ was dominated by plant species previously unknown to science that have become extinct in nearby human-affected ecosystems. Furthermore, natural vegetation had greater plant biomass with potentially as much as ten times more forest, but lower plant diversity. Contrary to our expectations, soils showed relatively little degradation when compared within a vegetation type, but differed mainly between forest and grassland ecosystems. At the landscape level, a presumed large-scale forest reduction resulted in a nowadays more acidic soilscape with higher carbon storage, partly ameliorating carbon loss through deforestation. Human impact in the high Andes, thus, had mixed effects on biodiversity, while soils and carbon stocks would have been mainly indirectly affected through a suggested large-scale vegetation change.
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    Franz Kossmat – Subdivision of the Variscan Mountains – a translation of the German text with supplementary notes 

    Meinhold, Guido
    History of Geo- and Space Sciences 2017; 8(1) p.29-51
    This work is in honour of Franz Kossmat (1871–1938) and his esteemed paper the Gliederung des varistischen Gebirgsbaues published 1927 in Abhandlungen des Sächsischen Geologischen Landesamts, Volume 1, pages 1 to 39. It constitutes the foundation of the general subdivision of the Central European Variscides into several geotectonic zones and the idea of large-scale nappe transport of individual units. In the English translation presented here an attempt is made to provide a readable text, which should still reflect Kossmat's style but would also be readable for a non-German speaking community either working in the Variscan Mountains or having specific interests in historical aspects of geosciences. Supplementary notes provide information about Kossmat's life and the content of the text. Kossmat's work is a superb example of how important geological fieldwork and mapping are for progress in geoscientific research.
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    Problems related to the taxonomic placement of incompletely preserved amber fossils: transfer of the Paleogene liverwort Cylindrocolea dimorpha (Cephaloziellaceae) to the extant Odontoschisma sect. Iwatsukia (Cephaloziaceae) 

    Feldberg, Kathrin; Váňa, Jiří; Schäfer-Verwimp, Alfons; Krings, Michael; Gröhn, Carsten; Schmidt, Alexander R.; Heinrichs, Jochen
    Fossil Record 2017; 20(2) p.147-157
    A revision of the Baltic and Bitterfeld amber fossils assigned to Cylindrocolea dimorpha (Cephaloziellaceae) has yielded evidence of the presence of multicellular, bifid underleaves, which have not previously been reported for this species and conflict with the current circumscription of the family. We transfer the fossil species to Odontoschisma (sect. Iwatsukia) and propose the new combination O. dimorpha of the Cephaloziaceae. Characteristics of the fossil include an overall small size of the plant, entire-margined, bifid leaves and underleaves, more or less equally thickened leaf cell walls, ventral branching that includes stoloniform branches with reduced leaves, and the lack of a stem hyalodermis and gemmae. Placement of the fossil in Cephaloziaceae profoundly affects divergence time estimates for liverworts based on DNA sequence variation with integrated information from the fossil record. Our reclassification concurs with hypotheses on the divergence times of Cephaloziaceae derived from DNA sequence data that provide evidence of a late Early Cretaceous to early Eocene age of the Odontoschisma crown group and an origin of O. sect. Iwatsukia in the Late Cretaceous to Oligocene.
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    A Burmese amber fossil of Radula (Porellales, Jungermanniopsida) provides insights into the Cretaceous evolution of epiphytic lineages of leafy liverworts 

    Bechteler, Julia; Schmidt, Alexander R.; Renner, Matthew A. M.; Wang, Bo; Pérez-Escobar, Oscar Alejandro; Schäfer-Verwimp, Alfons; Feldberg, Kathrin; Heinrichs, Jochen
    Fossil Record 2017; 20(2) p.201-213
    DNA-based divergence time estimates suggested major changes in the composition of epiphyte lineages of liverworts during the Cretaceous; however, evidence from the fossil record is scarce. We present the first Cretaceous fossil of the predominantly epiphytic leafy liverwort genus Radula in ca. 100 Myr old Burmese amber. The fossil's exquisite preservation allows first insights into the morphology of early crown group representatives of Radula occurring in gymnosperm-dominated forests. Ancestral character state reconstruction aligns the fossil with the crown group of Radula subg. Odontoradula; however, corresponding divergence time estimates using the software BEAST lead to unrealistically old age estimates. Alternatively, assignment of the fossil to the stem of subg. Odontoradula results in a stem age estimate of Radula of 227.8 Ma (95 % highest posterior density (HPD): 165.7–306.7) and a crown group estimate of 176.3 Ma (135.1–227.4), in agreement with analyses employing standard substitution rates (stem age 235.6 Ma (142.9–368.5), crown group age 183.8 Ma (109.9–289.1)). The fossil likely belongs to the stem lineage of Radula subg. Odontoradula. The fossil's modern morphology suggests that switches from gymnosperm to angiosperm phorophytes occurred without changes in plant body plans in epiphytic liverworts. The fossil provides evidence for striking morphological homoplasy in time. Even conservative node assignments of the fossil support older rather than younger age estimates of the Radula crown group, involving origins for most extant subgenera by the end of the Cretaceous and diversification of their crown groups in the Cenozoic.
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    Zhamanshin astrobleme provides evidence for carbonaceous chondrite and post-impact exchange between ejecta and Earth’s atmosphere 

    Magna, Tomáš; Žák, Karel; Pack, Andreas; Moynier, Frédéric; Mougel, Bérengère; Peters, Stefan; Skála, Roman; Jonášová, Šárka; Mizera, Jiří; Řanda, Zdeněk
    Nature Communications 2017; 8(1)
    Chemical fingerprints of impacts are usually compromised by extreme conditions in the impact plume, and the contribution of projectile matter to impactites does not often exceed a fraction of per cent. Here we use chromium and oxygen isotopes to identify the impactor and impact-plume processes for Zhamanshin astrobleme, Kazakhstan. ε54Cr values up to 1.54 in irghizites, part of the fallback ejecta, represent the 54Cr-rich extremity of the Solar System range and suggest a CI-like chondrite impactor. Δ17O values as low as -0.22‰ in irghizites, however, are incompatible with a CI-like impactor. We suggest that the observed 17O depletion in irghizites relative to the terrestrial range is caused by partial isotope exchange with atmospheric oxygen (Δ17O = -0.47‰) following material ejection. In contrast, combined Δ17O-ε54Cr data for central European tektites (distal ejecta) fall into the terrestrial range and neither impactor fingerprint nor oxygen isotope exchange with the atmosphere are indicated.Identifying the original impactor from craters remains challenging. Here, the authors use chromium and oxygen isotopes to indicate that the Zhamanshin astrobleme impactor was a carbonaceous chrondrite by demonstrating that depleted 17O values are due to exchange with atmospheric oxygen.
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    Raumordnungspolitik als Verdichtung politischer Kräfteverhältnisse 

    Mießner, Michael
    s u b \ u r b a n . zeitschrift für kritische stadtforschung 2017; 5(172) p.21-40
    Am Beispiel der Raumordnungspolitik der Bundesrepublik Deutschland der 1970er-Jahre wird im Beitrag mithilfe der historisch-materialistischen Politikanalyse die politische Verdichtung der Kräfteverhältnisse bezüglich Raumordnung analysiert. Es wird aufgezeigt, dass das Konzept der dezentralen Konzentration mittels Entwicklungszentren und -achsen zur bestimmenden raumordnungspolitischen Strategie für die Bearbeitung der räumlich ungleichen Entwicklung in der Bundesrepublik Deutschland wurde. Vor dem Hintergrund der sich real in den 1970er-Jahren vollziehenden räumlichen Entwicklung, in Form der dezentralen Konzentration, bot es den Parteienvertreter_innen die Möglichkeit, ihre ideologischen und parteipolitischen Vorstellungen mit diesem Konzept zu verbinden. Mit dem Konzept der dezentralen Konzentration wurde eine Strategie gewählt, die die bestehende räumliche Entwicklung protegierte und ihr nichts entgegensetzte.
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    Metallic Iron for Water Treatment: Lost Science in the West 

    Noubactep, Chicgoua
    Bioenergetics: Open Access 2017; 06(01): Art. 1000149
    not available
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    Diversity and composition of herbaceous angiosperms along gradients of elevation and forest-use intensity. 

    Gómez-Díaz, Jorge Antonio; Krömer, Thorsten; Kreft, Holger; Gerold, Gerhard; Carvajal-Hernández, César Isidro; Heitkamp, Felix
    PloS one 2017; 12(8): Art. e0182893
    Terrestrial herbs are important elements of tropical forests; however, there is a lack of research on their diversity patterns and how they respond to different intensities of forest-use. The aim of this study was to analyze the diversity of herbaceous angiosperms along gradients of elevation (50 m to 3500 m) and forest-use intensity on the eastern slopes of the Cofre de Perote, Veracruz, Mexico. We recorded the occurrence of all herbaceous angiosperm species within 120 plots of 20 m x 20 m each. The plots were located at eight study locations separated by ~500 m in elevation and within three different habitats that differ in forest-use intensity: old-growth, degraded, and secondary forest. We analyzed species richness and floristic composition of herb communities among different elevations and habitats. Of the 264 plant species recorded, 31 are endemic to Mexico. Both α- and γ-diversity display a hump-shaped relation to elevation peaking at 2500 m and 3000 m, respectively. The relative contribution of between-habitat β-diversity to γ-diversity also showed a unimodal hump whereas within-habitat β-diversity declined with elevation. Forest-use intensity did not affect α-diversity, but β-diversity was high between old-growth and secondary forests. Overall, γ-diversity peaked at 2500 m (72 species), driven mainly by high within- and among-habitat β-diversity. We infer that this belt is highly sensitive to anthropogenic disturbance and forest-use intensification. At 3100 m, high γ-diversity (50 species) was driven by high α- and within-habitat β-diversity. There, losing a specific forest area might be compensated if similar assemblages occur in nearby areas. The high β-diversity and endemism suggest that mixes of different habitats are needed to sustain high γ-richness of terrestrial herbs along this elevational gradient.
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    Making Fe0-Based Filters a Universal Solution for Safe Drinking Water Provision 

    Naseri, Elham; Ndé-Tchoupé, Arnaud; Mwakabona, Hezron; Nanseu-Njiki, Charles; Noubactep, Chicgoua; Njau, Karoli; Wydra, Kerstin
    Sustainability 2017; 9(7): Art. 1224
    Metallic iron (Fe0)-based filtration systems have the potential to significantly contribute to the achievement of the United Nations (UN) Sustainable Development Goals (SDGs) of substantially improving the human condition by 2030 through the provision of clean water. Recent knowledge on Fe0-based safe drinking water filters is addressed herein. They are categorized into two types: Household and community filters. Design criteria are recalled and operational details are given. Scientists are invited to co-develop knowledge enabling the exploitation of the great potential of Fe0 filters for sustainable safe drinking water provision (and sanitation).
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    Comparison of Multiple Linear Regression, Cubist Regression, and Random Forest Algorithms to Estimate Daily Air Surface Temperature from Dynamic Combinations of MODIS LST Data 

    Noi, Phan; Degener, Jan; Kappas, Martin
    Remote Sensing 2017; 9(5): Art. 398
    Recently, several methods have been introduced and applied to estimate daily air surface temperature (Ta) using MODIS land surface temperature data (MODIS LST). Among these methods, the most common used method is statistical modeling, and the most applied algorithms are linear/multiple linear regression models (LM). There are only a handful of studies using machine learning algorithm models such as random forest (RF) or cubist regression (CB). In particular, there is no study comparing different combinations of four MODIS LST datasets with or without auxiliary data using different algorithms such as multiple linear regression, random forest, and cubist regression for daily Ta-max, Ta-min, and Ta-mean estimation. Our study examines the mentioned combinations of four MODIS-LST datasets and shows that different combinations and differently applied algorithms produce various Ta estimation accuracies. Additional analysis of daily data from three climate stations in the mountain area of North West of Vietnam for the period of five years (2009 to 2013) with four MODIS LST datasets (AQUA daytime, AQUA nighttime, TERRA daytime, and TERRA nighttime) and two additional auxiliary datasets (elevation and Julian day) shows that CB and LM should be applied if MODIS LST data is used solely. If MODIS LST is used together with auxiliary data, especially in mountainous areas, CB or RF is highly recommended. This study proved that the very high accuracy of Ta estimation (R2 > 0.93/0.80/0.89 and RMSE ~1.5/2.0/1.6 C of Ta-max, Ta-min, and Ta-mean, respectively) could be achieved with a simple combination of four LST data, elevation, and Julian day data using a suitable algorithm.
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    Effects of conversion of native cerrado vegetation to pasture on soil hydro-physical properties, evapotranspiration and streamflow on the Amazonian agricultural frontier. 

    Nóbrega, Rodolfo L. B.; Guzha, Alphonce C.; Torres, Gilmar N.; Kovacs, Kristof; Lamparter, Gabriele; Amorim, Ricardo S. S.; Couto, Eduardo; Gerold, Gerhard
    PloS one 2017; 12(6): Art. e0179414
    Understanding the impacts of land-use change on landscape-hydrological dynamics is one of the main challenges in the Northern Brazilian Cerrado biome, where the Amazon agricultural frontier is located. Motivated by the gap in literature assessing these impacts, we characterized the soil hydro-physical properties and quantified surface water fluxes from catchments under contrasting land-use in this region. We used data from field measurements in two headwater micro-catchments with similar physical characteristics and different land use, i.e. cerrado sensu stricto vegetation and pasture for extensive cattle ranching. We determined hydraulic and physical properties of the soils, applied ground-based remote sensing techniques to estimate evapotranspiration, and monitored streamflow from October 2012 to September 2014. Our results show significant differences in soil hydro-physical properties between the catchments, with greater bulk density and smaller total porosity in the pasture catchment. We found that evapotranspiration is smaller in the pasture (639 ± 31% mm yr-1) than in the cerrado catchment (1,004 ± 24% mm yr-1), and that streamflow from the pasture catchment is greater with runoff coefficients of 0.40 for the pasture and 0.27 for the cerrado catchment. Overall, our results confirm that conversion of cerrado vegetation to pasture causes soil hydro-physical properties deterioration, reduction in evapotranspiration reduction, and increased streamflow.
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    Quantitative assessments of water-use efficiency in Temperate Eurasian Steppe along an aridity gradient. 

    Chen, Yizhao; Li, Jianlong; Ju, Weimin; Ruan, Honghua; Qin, Zhihao; Huang, Yiye; Jeelani, Nasreen; Padarian, José; Propastin, Pavel
    PloS one 2017; 12(7): Art. e0179875
    Water-use efficiency (WUE), defined as the ratio of net primary productivity (NPP) to evapotranspiration (ET), is an important indicator to represent the trade-off pattern between vegetation productivity and water consumption. Its dynamics under climate change are important to ecohydrology and ecosystem management, especially in the drylands. In this study, we modified and used a late version of Boreal Ecosystem Productivity Simulator (BEPS), to quantify the WUE in the typical dryland ecosystems, Temperate Eurasian Steppe (TES). The Aridity Index (AI) was used to specify the terrestrial water availability condition. The regional results showed that during the period of 1999-2008, the WUE has a clear decreasing trend in the spatial distribution from arid to humid areas. The highest annual average WUE was in dry and semi-humid sub-region (DSH) with 0.88 gC mm-1 and the lowest was in arid sub-region (AR) with 0.22 gC mm-1. A two-stage pattern of WUE was found in TES. That is, WUE would enhance with lower aridity stress, but decline under the humid environment. Over 65% of the region exhibited increasing WUE. This enhancement, however, could not indicate that the grasslands were getting better because the NPP even slightly decreased. It was mainly attributed to the reduction of ET over 70% of the region, which is closely related to the rainfall decrease. The results also suggested a similar negative spatial correlation between the WUE and the mean annual precipitation (MAP) at the driest and the most humid ends. This regional pattern reflected the different roles of water in regulating the terrestrial ecosystems under different aridity levels. This study could facilitate the understanding of the interactions between terrestrial carbon and water cycles, and thus contribute to a sustainable management of nature resources in the dryland ecosystems.
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