Cotton canopy reflectance under variable solar zenith angles: Implications of use in evapotranspiration models     

Christopher M. U. Neale  Maria P. Gonzalez-Dugo  Angelica Serrano-Perez  Isidro Campos  Luciano Mateos 《水文研究》2021,35(6):e14162

Evapotranspiration (ET) is an important parameter in hydrologic processes and modelling. In agricultural watersheds with competing uses of fresh water including irrigated agriculture, estimating crop evapotranspiration (ET_c) accurately is critical for improving irrigation system and basin water management. The use of remote sensing-based basal crop coefficients is becoming a common method for estimating crop evapotranspiration for multiple crops over large areas. The Normalized Difference Vegetation Index (NDVI) and the Soil Adjusted Vegetation Index (SAVI), based on reflectance in the red and near-infrared bands, are commonly used for this purpose. In this paper, we examine the effects of row crop orientation and soil background darkening due to shading and soil surface wetness on these two vegetation indices through modelling, coupled with a field experiment where canopy reflectance of a cotton crop at different solar zenith angles, was measured with a portable radiometer. The results show that the NDVI is significantly more affected than the SAVI by background shading and soil surface wetness, especially in north–south oriented rows at higher latitudes and could lead to a potential overestimation of crop evapotranspiration and irrigation water demand if used for basal crop coefficient estimation. Relationships between the analysed vegetation indices and canopy biophysical parameters such as crop height, fraction of cover and leaf area index also were developed for both indices.  相似文献   

Gentrification as space domestication. The High Line Art case     

Pier Luigi Sacco  Maria Tartari  Guido Ferilli  Giorgio Tavano Blessi 《Urban geography》2019,40(4):529-554

In this paper, we critically examine the role of artistic locational choices and practices in the context of gentrification processes in urban renewal contexts. We characterize gentrification as a form of domestication of space, and explore the extent to which artistic choices and practices relate to such process with reference to the deontological dilemma of legitimization within the art system vs. responsible empowerment of vulnerable local constituencies. We illustrate our argument with an analysis of the High Line Art project, and show how this can be considered as a textbook example of art-driven space domestication leading to brutal forms of gentrification. We comment on the threat that this provides to the social credibility of artistic practices as an agency of responsible social change.  相似文献   

An algorithm to resolve γ-rays from charged cosmic rays with DAMPE     

Zun-Lei Xu  Kai-Kai Duan  Zhao-Qiang Shen  Shi-Jun Lei  Tie-Kuang Dong  Fabio Gargano  Simone Garrappa  Dong-Ya Guo  Wei Jiang  Xiang Li  Yun-Feng Liang  Mario Nicola Mazziotta  Maria Fernanda Munoz Salinas  Meng Su  Valerio Vagelli  Qiang Yuan  Chuan Yue  Jing-Jing Zang  Ya-Peng Zhang  Yun-Long Zhang  Stephan Zimmer 《天文和天体物理学研究(英文版)》2018,(3)

The DArk Matter Particle Explorer(DAMPE),also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.  相似文献   

Natural highways for end-of-life solutions in the LEO region     

Elisa Maria Alessi  Giulia Schettino  Alessandro Rossi  Giovanni B. Valsecchi 《Celestial Mechanics and Dynamical Astronomy》2018,130(5):34

We present the main findings of a dynamical mapping performed in the Low Earth Orbit region. The results were obtained by propagating an extended grid of initial conditions, considering two different epochs and area-to-mass ratios, by means of a singly averaged numerical propagator. It turns out that dynamical resonances associated with high-degree geopotential harmonics, lunisolar perturbations and Solar radiation pressure can open natural deorbiting highways. For area-to-mass ratios typical of the orbiting intact objects, these corridors can be exploited only in combination with the action exerted by the atmospheric drag. For satellites equipped with an area augmentation device, we show the boundary of application of the drag, and where the Solar radiation pressure can be exploited.  相似文献   

Detecting the stepwise propagation of the Eastern Sicily thrust belt (Italy): insight from thermal and thermochronological constraints     

Lea Di Paolo  Valerio Olivetti  Sveva Corrado  Luca Aldega  Maria Laura Balestrieri  Rosanna Maniscalco 《地学学报》2014,26(5):363-371

An extensive dataset of vitrinite reflectance, FTIR parameters on organic matter, illite content in mixed layers illite‐smectite, apatite fission tracks and U‐Th/He dating has been used to reconstruct the stepwise propagation of the Eastern Sicily fold‐and‐thrust belt during Late Palaeogene and Neogene times. The results indicate that the fold‐and‐thrust belt is divisible into two levels of thermal maturity. These levels consist of a less evolved level of thermal maturity that records limited sedimentary burial and minor heating, and a more evolved level of thermal maturity that indicates tectonic burial and exhumation at different times. Deformation and exhumation of shallowly buried units are linked to wedge forward propagation by low‐angle thrusts, whereas the evolution of deeply buried units is associated with tectonic imbrications by duplex formation and steep thrusts. The two tectonic styles alternate during evolution of the fold‐and‐thrust belt under low erosion rates.  相似文献   

Did the “Autochthonous” European foreland of Corsica Island (France) experience Alpine subduction?     

Maria Di Rosa  Chiara Frassi  Michele Marroni  Francesca Meneghini  Luca Pandolfi 《地学学报》2020,32(1):34-43

Despite the important role played by the Sardinia‐Corsica block in the reconstruction of the Western Mediterranean geodynamics, the extent of involvement of the “Autochthonous” European margin exposed in Corsica (France) (i.e., Hercynian Corsica) in the Alpine orogeny remains uncertain. Stratigraphic and sedimentological studies in the post‐Variscan deposits on the Hercynian Corsica are scarce and even scarcer are the structural and metamorphic constraints. To face these uncertainties, we present new stratigraphic, structural and metamorphic data from the area of Razzo Bianco, Central Corsica, where a complete sequence belonging to the European continental margin is exposed. Field and structural investigations demonstrate that the sequence represents the easternmost edge of the downgoing European plate. Metamorphic studies on the Eocene deposits indicate that the margin was buried at depth up to blueschist facies conditions and, subsequently, it was progressively exhumed mainly through the activation of oblique top‐to‐the NW shear zones.  相似文献   

A Long Way to Go: Collective Paths to Racial Justice in Geography     

Caroline Faria  Bisola Falola  Jane Henderson  Rebecca Maria Torres 《The Professional geographer》2019,71(2):364-376

Despite decades of recognition and worry about diversity, our discipline remains persistently white. That is, it is dominated by white bodies and it continues to conform to norms, practices, and ideologies of whiteness. This is a loss. At best, it limits the possibilities and impact of our work as geographers. At worst, it perpetuates harmful exclusions in our discipline: its working environments, its institutions, and its knowledge production. This remains deeply concerning for many geographers, and there has been important research, commentary, and institutional activity over the years. Yet, research shows us that little meaningful progress has been made. We know that mentoring is one vital part of the journey toward change. As such, we reflect here on our experience developing a research collective built on a transformative mentoring practice. We outline the key challenges, strategies, and tentative successes of the collective in supporting women of color undergraduate, graduate, and faculty geographers, arguing that such feminist formations are a vital part of the path to intellectual racial justice in our field. Key Words: diversity, feminist geography, higher education, mentoring, race.  相似文献   

Debris-flow Indicator for an early warning system in the Aosta valley region     

Ponziani  Michel  Pogliotti  Paolo  Stevenin  Hervé  Ratto  Sara Maria 《Natural Hazards》2020,104(2):1819-1839

Natural Hazards - Aosta Valley, an Alpine region in north-western Italy, has an early warning system (EWS) that issues hydrogeological alerts based on hydrological modelling and rainfall thresholds...  相似文献   

Impact of drilling mud on chemistry and microbiology of an Upper Triassic groundwater after drilling and testing an exploration well for aquifer thermal energy storage in Berlin (Germany)     

Simona Regenspurg  Mashal Alawi  Guido Blöcher  Maria Börger  Stefan Kranz  Ben Norden  Ali Saadat  Traugott Scheytt  Lioba Virchow  Andrea Vieth-Hillebrand 《Environmental Earth Sciences》2018,77(13):516

After completion of an exploration well, sandstones of the Exter Formation were hydraulically tested to determine the hydraulic properties and to evaluate chemical and microbial processes caused by drilling and water production. The aim was to determine the suitability of the formation as a reservoir for aquifer thermal energy storage. The tests revealed a hydraulic conductivity of 1–2 E-5 m/s of the reservoir, resulting in a productivity index of 0.6–1 m³/h/bar. A hydraulic connection of the Exter Formation to the overlaying, artesian “Rupelbasissand” cannot be excluded. Water samples were collected for chemical and microbiological analyses. The water was similarly composed as sea water with a maximum salinity of 24.9 g/L, dominated by NaCl (15.6 g/L Cl and 7.8 g/L Na). Until the end of the tests, the water was affected by drilling mud as indicated by the high pH (8.9) and high bicarbonate concentration (359 mg/L) that both resulted from the impact of sodium carbonate (Na₂CO₃) additives. The high amount of dissolved organic matter (>?58 mg/L) and its molecular-weight distribution pattern indicated that residues of cellulose, an ingredient of the drilling mud, were still present at the end of the tests. Clear evidence of this contamination gave the measured uranine that was added as a tracer into the drilling mud. During fluid production, the microbial community structure and abundance changed and correlated with the content of drilling mud. Eight taxa of sulfate-reducing bacteria, key organisms in processes like bio-corrosion and bio-clogging, were identified. It can be assumed that their activity will be affected during usage of the reservoir.  相似文献   

Ecotoxicological evaluation of dredged sediments from Rodrigo de Freitas Lagoon (Rio de Janeiro State,Brazil) using bioassays with earthworms and collembolans     

Mariana Vezzone  Ricardo Cesar  Helena Polivanov  Aline Serrano  Danielle Siqueira  Leticia Abreu  Miriam Bianchi  Maria Elizabeth Correia  Zuleica Castilhos  Tácio de Campos 《Environmental Earth Sciences》2018,77(21):743

The toxicity and metal bioavailability were studied in dredged sediments from Rodrigo de Freitas Lagoon (Rio de Janeiro, RJ, Brazil) using acute and avoidance tests with Eisenia andrei, and reproduction tests with Folsomia candida. The sediment was mixed with an artificial soil, and two natural soils (ferralsol and chernosol—representative Brazilian tropical soils) to obtain the following doses: 1, 3, 6, 12, 18, 24 and 30%. Total metal concentrations were determined in the sediment to support the interpretation of ecotoxicological data. Metal concentrations in the mixtures were in agreement with the threshold limits established by Brazilian law. However, significant avoidance responses were found on doses ≥?3% and were the most sensitive endpoint. Earthworm mortality found in artificial soil mixtures (LC50?=?3.9) suggests higher toxicity levels than those obtained in ferralsol (LC50?=?7.6%) and chernosol (11.0%) treatments. Earthworm mortality, avoidance responses and collembolan reproduction levels found in ferralsol mixtures (LC50?=?9.2; avoidance EC50?=?2.3%; reproduction EC50?=?2.8%) were higher compared to chernosol treatments (LC50?=?11.0%; avoidance EC50?=?4.3%; reproduction EC50?=?4.9%). The reduction of toxicity levels in chernosol mixtures is probably due to the abundance of expansive clay minerals in chernosols with capacity of adsorbing metals and other xenobiotic substances from soil pore water, decreasing metal bioavailability. Finally, threshold limits defined by Brazilian legislation for soil quality and land disposal of dredged sediments are not sufficient to prevent noxious effects on soil fauna and should be complemented with a preliminary ecotoxicological evaluation.  相似文献