To see the other types of publications on this topic, follow the link: Global ground fields.
Journal articles on the topic 'Global ground fields'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Global ground fields.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Skačkauskas, Paulius, and Edgar Sokolovskij. "Analysis of the Hybrid Global Path Planning Algorithm for Different Environments." Transport and Telecommunication Journal 20, no. 1 (February 1, 2019): 1–11. http://dx.doi.org/10.2478/ttj-2019-0001.
Full textAbstract:
Abstract To achieve the overall goal of realising an efficient and advantageous participation of autonomous ground vehicles in the transport system as fast as possible, a lot of work is being done in different and specific research fields. One of the most important research fields, which has a large impact on safe autonomous ground vehicle realisation, is the development of path planning algorithms. Therefore, this work describes in detail the development and application of a hybrid path planning algorithm. The described algorithm is based on classical and heuristic path planning approaches and can be applied in unstructured and structured environments. The efficiency of the algorithm was investigated by applying the algorithm and executing theoretical and experimental tests. The theoretical and experimental tests were executed while optimising different complexity paths. Results analysis demonstrated that the described algorithm can generate a smooth, dynamically feasible and collision-free path.
2
Rothe, Delf, and David Shim. "Sensing the ground: On the global politics of satellite-based activism." Review of International Studies 44, no. 3 (January 23, 2018): 414–37. http://dx.doi.org/10.1017/s0260210517000602.
Full textAbstract:
AbstractIn recent years, satellite imagery, previously restricted to the defence and intelligence communities, has been made available to a range of non-state actors as well. Non-governmental organisations, journalists, and celebrities such as George Clooney now use remote sensing data like digital Sherlock Holmeses to investigate and reveal human rights abuses, political violence, environmental destruction, and eco-crimes from a distance. It is often said that the increasing availability and applicability of remote sensing technologies has contributed to the rise of what can be called ‘satellite-based activism’ empowering non-state groups to challenge state practices of seeing and showing. In this article we argue that NGO activism is not challenging the sovereign gaze of the state but, on the contrary, actually reinforcing it. We will bolster our arguments in this regard in two prominent fields of non-governmental remote sensing: human rights and environmental governance.
3
Bodeker, Greg E., Jan Nitzbon, Jordis S. Tradowsky, Stefanie Kremser, Alexander Schwertheim, and Jared Lewis. "A global total column ozone climate data record." Earth System Science Data 13, no. 8 (August 11, 2021): 3885–906. http://dx.doi.org/10.5194/essd-13-3885-2021.
Full textAbstract:
Abstract. Total column ozone (TCO) data from multiple satellite-based instruments have been combined to create a single near-global daily time series of ozone fields at 1.25∘ longitude by 1∘ latitude spanning the period 31 October 1978 to 31 December 2016. Comparisons against TCO measurements from the ground-based Dobson and Brewer spectrophotometer networks are used to remove offsets and drifts between the ground-based measurements and a subset of the satellite-based measurements. The corrected subset is then used as a basis for homogenizing the remaining data sets. The construction of this database improves on earlier versions of the database maintained first by the National Institute of Water and Atmospheric Research (NIWA) and now by Bodeker Scientific (BS), referred to as the NIWA-BS TCO database. The intention is for the NIWA-BS TCO database to serve as a climate data record for TCO, and to this end, the requirements for constructing climate data records, as detailed by GCOS (the Global Climate Observing System), have been followed as closely as possible. This new version includes a wider range of satellite-based instruments, uses updated sources of satellite data, extends the period covered, uses improved statistical methods to model the difference fields when homogenizing the data sets, and, perhaps most importantly, robustly tracks uncertainties from the source data sets through to the final climate data record which is now accompanied by associated uncertainty fields. Furthermore, a gap-free TCO database (referred to as the BS-filled TCO database) has been created and is documented in this paper. The utility of the NIWA-BS TCO database is demonstrated through an analysis of ozone trends from November 1978 to December 2016. Both databases are freely available for non-commercial purposes: the DOI for the NIWA-BS TCO database is https://doi.org/10.5281/zenodo.1346424 (Bodeker et al., 2018) and is available from https://zenodo.org/record/1346424. The DOI for the BS-filled TCO database is https://doi.org/10.5281/zenodo.3908787 (Bodeker et al., 2020) and is available from https://zenodo.org/record/3908787. In addition, both data sets are available from http://www.bodekerscientific.com/data/total-column-ozone (last access: June 2021).
4
Heise, S., G. Dick, G. Gendt, T. Schmidt, and J. Wickert. "Integrated water vapor from IGS ground-based GPS observations: initial results from a global 5-min data set." Annales Geophysicae 27, no. 7 (July 16, 2009): 2851–59. http://dx.doi.org/10.5194/angeo-27-2851-2009.
Full textAbstract:
Abstract. Ground based GPS zenith path delay (ZPD) measurements are well established as a powerful tool for integrated water vapor (IWV) observation. The International GNSS Service (IGS) provides ZPD data of currently more than 300 globally distributed GPS stations. To derive IWV from these data, meteorological information (ground pressure and mean temperature above the station) are needed. Only a limited number of IGS stations is equipped with meteorological ground sensors up to now. Thus, meteorological data for IWV conversion are usually derived from nearby ground meteorological observations (ground pressure) and meteorological analyses (mean temperature). In this paper we demonstrate for the first time the applicability of ground pressure data from ECMWF meteorological analysis fields in this context. Beside simplified data handling (no single station data and quality control) this approach allows for IWV derivation if nearby meteorological stations are not available. Using ECMWF ground pressure and mean temperature data the new IGS 5-min ZPD data set has been converted to IWV for the first time. We present initial results from selected stations with ground meteorological sensors including pressure and temperature comparisons between ECMWF and local measurements. The GPS IWV is generally validated by comparison with ECMWF IWV. The ECMWF derived station meteorological data are compared with local measurements at all accordingly equipped stations. Based on this comparison, the mean error (in terms of standard deviation) introduced by time interpolation of the 6-hourly ECMWF data is estimated below 0.2 mm IWV.
5
Spergel, David, and Robert Williams. "Global Coordination: What are the Next Steps?" Proceedings of the International Astronomical Union 11, A29A (August 2015): 276–79. http://dx.doi.org/10.1017/s1743921316003045.
Full textAbstract:
From the transit expeditions of 1761 to JWST, ALMA, and the SKA, international projects have played an important role in driving astronomy and heliophysics. Over the past two decades, the increasing complexity and cost of new facilities, the constrained amount of funding available from individual sources, and the rapidly increasing volume of data produced by newer facilities have made international collaboration on large ground- and space-based facilities essential to moving the fields forward. As international cooperation becomes commonplace, data-sharing policies have become ever more important. All IAU members have a stake in the policy decisions made by nations and various scientific consortiums concerning data access and international collaborations. This focus meeting provided a forum to discuss how to improve coordination of global strategic planning in astronomy, astrophysics, and heliophysics in order to maximize the scientific return from research facilities.
6
Voudouri, Aikaterini, Evgenia Chaideftou, and Athanassios Sfougaris. "Topsoil Seed Bank as Feeding Ground for Farmland Birds: A Comparative Assessment in Agricultural Habitats." Land 10, no. 9 (September 14, 2021): 967. http://dx.doi.org/10.3390/land10090967.
Full textAbstract:
The topsoil seed bank was studied in four types of agricultural bird habitats: fields with cereals, maize, clover and tilled fields of a Mediterranean plain to determine the potentially richest habitat based on food supply for the wintering farmland birds. The diversity and abundance of topsoil seeds differed between seasons but did not differ significantly between habitats. The cereal habitat was the richest in food supply for the overwintering of farmland birds. The topsoil seed bank was dominated by Chenopodium album, Polygonum aviculare and Amaranthus retroflexus. The findings of this study provide insight for low-intensity management of higher-elevation mount agricultural areas of southern Mediterranean by preserving seed-rich habitats for farmland avifauna.
7
Sensoy Bahar, Ozge. "A Promising Partnership: Uncovering the Middle Ground Between Social Innovation and Social Work." Research on Social Work Practice 27, no. 2 (August 3, 2016): 131–33. http://dx.doi.org/10.1177/1049731516658769.
Full textAbstract:
This response article discusses opportunities to bridge social work and social innovation as a promising partnership to address the issues impacting vulnerable populations across the global context. It starts by revisiting the conceptualization of innovation in social work and continues by considering factors that contribute to the growing interest in social innovation and related concepts. This article concludes by discussing differences in social work and social innovation and how these differences can be turned into opportunities for a fruitful partnership that can push both fields forward.
8
Banerjee, D. "Observational review on global waves." Proceedings of the International Astronomical Union 3, S247 (September 2007): 369–76. http://dx.doi.org/10.1017/s1743921308015111.
Full textAbstract:
AbstractWith multi-wavelength observations from ground and space-based instruments it has been possible to detect waves in a number of different wavelengths simultaneously and to, consequently, study their propagation properties. High-resolution wave observations combined with forward MHD modelling can give an unprecedented insight into the connectivity of the magnetized solar atmosphere, which further gives us a realistic chance to construct the structure of the magnetic field in the stellar atmosphere. This type of exploration is also termed as magnetic seismology. In this review I will focus on global waves, like EIT waves. I will also address the possibility of finding out the properties of magnetic structures while studying the interaction of global waves with coronal loops. A Promising new way to probe stellar atmosphere is to use our knowledge of coronal seismology on the Sun and to apply it to more distant stars. It will also enable us to measure properties such as the lengths of loops linked with stellar flares and the strengths of coronal magnetic fields on stars. In the last part I will review the current status of the stellar coronal seismology.
9
Zhang, Xue Qin, Xu Zhang, and Xin Wen Yu. "Application Research of Satellite-Ground Positioning Technology in Forestry." Applied Mechanics and Materials 530-531 (February 2014): 715–23. http://dx.doi.org/10.4028/www.scientific.net/amm.530-531.715.
Full textAbstract:
Global satellite positioning technology has been applied to transport, mapping, security, agriculture, forestry and other fields. In this study, we summarized the application of satellite positioning technology in forestry, pointed out issues of low signal amplitude, and low accuracy of positioning in practical application. This paper introduced the theories of several commonly used assist positioning technologies, such as, Wi-Fi positioning, wireless sensor network positioning and inertial navigation, analyzed its application in forestry base on its characteristics of these positioning technologies, then proposed the technical method of the combining positioning. Designed the locating scheme of forestry based on nature reserve patrol business, and briefly introduced its basic theories. In this study, we analyzed the feasibility of the application of wireless positioning in forestry by control variables and regression analysis.
10
Chrzanowski, Adam, Chen Yong-qi, Roger W. Leeman, Julio Leal, and Maraven. "Integration of the global positioning system with geodetic leveling surveys in ground subsidence studies." CISM journal 43, no. 4 (January 1989): 377–86. http://dx.doi.org/10.1139/geomat-1989-0039.
Full textAbstract:
Integration of GPS measurements with terrestrial geodetic leveling has been implemented by the authors in monitoring ground subsidence in oil fields in Venezuela in an area of about 50 km x 50 km. The subsidence rate reaches up to 20 cm/year. A mathematical model for combining the GPS surveys with dynamic leveling measurements has been developed by utilizing the well known University of New Brunswick generalized method of deformation analysis. The implementation of GPS was preceded by test surveys (5 survey campaigns) in Canada on a network with 0.7 km to 30 km baselines, using TI 4100, WM101, and Trimble 4000SX receivers, and on a portion of the monitoring network in Venezuela (2 survey campaigns) using WM101 receivers. The accuracy of the test surveys has been evaluated using MINQE technique and by comparing the subsidences determined with GPS and precise leveling. The results indicate that with C/A-code receivers and with the present geometry of the satellite distribution, the vertical component of the short and medium (up to 30 km) length of the GPS baselines can be determined with an accuracy ranging from 15 mm in a moderate climate to 30 mm in hot and humid conditions.
11
Albergel, C., G. Balsamo, P. de Rosnay, J. Muñoz-Sabater, and S. Boussetta. "A bare ground evaporation revision in the ECMWF land-surface scheme: evaluation of its impact using ground soil moisture and satellite microwave data." Hydrology and Earth System Sciences 16, no. 10 (October 16, 2012): 3607–20. http://dx.doi.org/10.5194/hess-16-3607-2012.
Full textAbstract:
Abstract. In situ soil moisture data from 122 stations across the United States are used to evaluate the impact of a new bare ground evaporation formulation at ECMWF. In November 2010, the bare ground evaporation used in ECMWF's operational Integrated Forecasting System (IFS) was enhanced by adopting a lower stress threshold than for the vegetation, allowing a higher evaporation. It results in more realistic soil moisture values when compared to in situ data, particularly over dry areas. Use was made of the operational IFS and offline experiments for the evaluation. The latter are based on a fixed version of the IFS and make it possible to assess the impact of a single modification, while the operational analysis is based on a continuous effort to improve the analysis and modelling systems, resulting in frequent updates (a few times a year). Considering the field sites with a fraction of bare ground greater than 0.2, the root mean square difference (RMSD) of soil moisture is shown to decrease from 0.118 m3 m−3 to 0.087 m3 m−3 when using the new formulation in offline experiments, and from 0.110 m3 m−3 to 0.088 m3 m−3 in operations. It also improves correlations. Additionally, the impact of the new formulation on the terrestrial microwave emission at a global scale is investigated. Realistic and dynamically consistent fields of brightness temperature as a function of the land surface conditions are required for the assimilation of the SMOS data. Brightness temperature simulated from surface fields from two offline experiments with the Community Microwave Emission Modelling (CMEM) platform present monthly mean differences up to 7 K. Offline experiments with the new formulation present drier soil moisture, hence simulated brightness temperature with its surface fields are larger. They are also closer to SMOS remotely sensed brightness temperature.
12
Albergel, C., G. Balsamo, P. de Rosnay, J. Muñoz-Sabater, and S. Boussetta. "A bare ground evaporation revision in the ECMWF land-surface scheme: evaluation of its impact using ground soil moisture and satellite microwave data." Hydrology and Earth System Sciences Discussions 9, no. 5 (May 30, 2012): 6715–52. http://dx.doi.org/10.5194/hessd-9-6715-2012.
Full textAbstract:
Abstract. In situ soil moisture data from 122 stations across the United States are used to evaluate the impact of a new bare ground evaporation formulation at ECMWF. In November 2010 the bare ground evaporation used in ECMWF's operational Integrated Forecasting System (IFS) was enhanced by adopting a lower stress threshold than for the vegetation, allowing a higher evaporation. It results in more realistic soil moisture values when compared to in situ data, particularly over dry areas. Use was made of the operational IFS and offline experiments for the evaluation. The latter are based on a fixed version of the IFS and make it possible to assess the impact of a single modification while the operational analysis is based on a continuous effort to improve the analysis and modelling systems, resulting in frequent updates (few times a year). Considering the field sites with a fraction of bare ground greater than 0.2, the root mean square difference (RMSD) of soil moisture is shown to decrease from 0.118 m3 m−3 to 0.087 m3 m−3 when using the new formulation in offline experiments, and from 0.110 m3 m−3 to 0.088 m3 m−3 in operations. It also improves correlations. Additionally the impact of the new formulation on the terrestrial microwave emission at a global scale is investigated. Realistic and dynamically consistent fields of brightness temperature as a function of the land surface conditions are required for the assimilation of the SMOS data. Brightness temperature simulated from surface fields from two offline experiments with the Community Microwave Emission Modelling (CMEM) platform present monthly mean differences up to 7 K. Offline experiment with the new formulation presents drier soil moisture, hence simulated brightness temperature with its surface fields are larger. They are also closer to SMOS remotely sensed brightness temperature.
13
Takaku, J., T. Tadono, and K. Tsutsui. "Generation of High Resolution Global DSM from ALOS PRISM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-4 (April 23, 2014): 243–48. http://dx.doi.org/10.5194/isprsarchives-xl-4-243-2014.
Full textAbstract:
Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM), one of onboard sensors carried on the Advanced Land Observing Satellite (ALOS), was designed to generate worldwide topographic data with its optical stereoscopic observation. The sensor consists of three independent panchromatic radiometers for viewing forward, nadir, and backward in 2.5 m ground resolution producing a triplet stereoscopic image along its track. The sensor had observed huge amount of stereo images all over the world during the mission life of the satellite from 2006 through 2011. We have semi-automatically processed Digital Surface Model (DSM) data with the image archives in some limited areas. The height accuracy of the dataset was estimated at less than 5 m (rms) from the evaluation with ground control points (GCPs) or reference DSMs derived from the Light Detection and Ranging (LiDAR). Then, we decided to process the global DSM datasets from all available archives of PRISM stereo images by the end of March 2016. This paper briefly reports on the latest processing algorithms for the global DSM datasets as well as their preliminary results on some test sites. The accuracies and error characteristics of datasets are analyzed and discussed on various fields by the comparison with existing global datasets such as Ice, Cloud, and land Elevation Satellite (ICESat) data and Shuttle Radar Topography Mission (SRTM) data, as well as the GCPs and the reference airborne LiDAR/DSM.
14
ROBERTS, C. D., J. PRASCHIFKA, and R. T. CAHILL. "A CHIRALLY SYMMETRIC EFFECTIVE ACTION FOR VECTOR AND AXIAL VECTOR FIELDS IN A GLOBAL COLOR SYMMETRY MODEL OF QCD." International Journal of Modern Physics A 04, no. 07 (April 20, 1989): 1681–733. http://dx.doi.org/10.1142/s0217751x89000674.
Full textAbstract:
We consider the quantum field theory of a model of an extended Nambu-Jona-Lasinio type with a QCD based nonlocal fermion current-current interaction which has global SU(Nc) symmetry. We obtain an exact bosonization of this model in four Euclidean dimensions using auxiliary bilocal fields and discuss the dynamical breakdown of chiral symmetry in the massless fermion limit. A local field bosonization is obtained by decomposing the bilocal fields in terms of complete orthonormal sets of functions with the expansion coefficients, which are local functions, identified as the local meson fields. Retaining the ground state pseudoscalar, vector and pseudovector local fields we obtain a local effective action for this sector of the theory. The derivative expansion of the fermionic determinant necessary to obtain this local action is self-regularizing because of the bilocal substructure present in the model which is manifest in the form factors that are associated with the local fields. In our local action the value of each coefficient depends critically on the underlying fermionic dynamics through these form factors and the vacuum functions. As a consequence of this the vector and pseudovector fields in the theory are best interpreted as simple fermion-antifermion bound states rather than as massive Yang-Mills fields or exotic composites of the pseudoscalars; interpretations that we find are not in general admitted when models such as the GCM are treated correctly. Identifying then the physical vector and pseudovector fields with the linearly transforming chiral partners introduced by the bosonization, we obtain an effective action for this sector of the meson spectrum which predicts values for the kinematic and dynamic quantities associated with these fields.
15
FELTNER, KIMBERLY A., and LYNNE KIORPES. "Global visual processing in macaques studied using Kanizsa illusory shapes." Visual Neuroscience 27, no. 3-4 (April 30, 2010): 131–38. http://dx.doi.org/10.1017/s0952523810000088.
Full textAbstract:
AbstractThe ability to extract form information from a visual scene, for object recognition or figure–ground segregation, is a fundamental visual system function. Many studies of nonhuman primates have addressed the neural mechanisms involved in global form processing, but few have sought to demonstrate this ability behaviorally. In this study, we probed global visual processing in macaque monkeys (Macaca nemestrina) using classical Kanizsa illusory shapes as an assay of global form perception. We trained three monkeys on a “similarity match-to-sample” form discrimination task, first with complete forms embedded in fields of noncontour-inducing “pacman” elements. We then tested them with classic Kanizsa illusory shapes embedded in fields of randomly oriented elements. Two of the three subjects reached our criterion performance level of 80% correct or better on four of five illusory test conditions, demonstrating clear evidence of Kanizsa illusory form perception; the third subject mastered three of five conditions. Performance limits for illusory form discrimination were obtained by manipulating support ratio and by measuring threshold for discriminating “fat” and “thin” illusory squares. Our results indicate that macaque monkeys are capable of global form processing similarly to humans and that the perceptual mechanisms for “filling-in” contour gaps exist in macaques as they do in humans.
16
Tadesse, Alemu, and Emmanouil N. Anagnostou. "A Statistical Approach to Ground Radar-Rainfall Estimation." Journal of Atmospheric and Oceanic Technology 22, no. 11 (November 1, 2005): 1720–32. http://dx.doi.org/10.1175/jtech1796.1.
Full textAbstract:
Abstract This paper presents development of a statistical procedure for estimation of ensemble rainfall fields from a combination of ground radar observations and in situ rain gauge measurements. The uncertainty framework characterizes radar-rainfall estimation algorithm limitation accounting for rain gauge sampling uncertainty. The procedure is applied on a multicomponent rainfall estimation algorithm, which utilizes a rain-path attenuation correction technique, a power-law reflectivity-to-rainfall (Z–R) relationship, and a parameter to differentiate between convective (C) and stratiform (S) regimes in the Z–R conversion. Uncertainty is explicitly accounted for by evaluating the algorithm’s parameter set posterior probability density function (known as parameters’ equifinality) on the basis of the Generalized Likelihood Uncertainty Estimation (GLUE) framework. The study is facilitated by NASA’s C-band Doppler radar [named the Tropical Ocean Global Atmosphere (TOGA)] observations and four dense rain gauge clusters available from the Tropical Rainfall Measuring Mission (TRMM)-Large-Scale Biosphere–Atmosphere (LBA) experiment, conducted between January and February of 1999 in Southwest Amazon. Statistics are proposed for jointly evaluating the wideness of radar retrieval uncertainty limits [uncertainty ratio (UR)] and the percentage of observations that fall within those error bounds [exceedance ratio (ER)]. Results show that the parameter range selected in GLUE could characterize the radar-rainfall estimation uncertainty. Combined assessment of UR and ER for a varying range of parameters’ equifinality provides an objective basis for comparing rain retrieval algorithms and determining uncertainty bounds. Ensemble radar-rainfall fields derived on the basis of this procedure can be used to statistically assess satellite rain retrieval algorithms and derive ensemble hydrologic predictions driven by radar-rainfall input (e.g., runoff and soil moisture).
17
Dimitrova, Svetla. "Measurement of Methane and Other Atmospheric Pollutants Emitted by Flooded Paddy Fields." Visegrad Journal on Bioeconomy and Sustainable Development 7, no. 1 (May 1, 2018): 31–34. http://dx.doi.org/10.2478/vjbsd-2018-0006.
Full textAbstract:
Abstract The increase of methane concentration has been established during the last decades. This gas has a relative potential for thermal absorption, 30 times higher than CO2, which means that it is more active in the interaction with the ozone and its blocking. About 70% of the global total emission of methane in the atmosphere is of biogenic origin. Flooded paddy fields are one of the main sources of atmosphere pollutions with methane. Irrigation of rice fields by overflowing reduces the feeding of the ground with oxygen from the air. This in turn affects the fermentation of organic substances in the ground. Methane is the final product in this process. The measurement was performed in the phase of rice earing by an authorized laboratory associated to the Executive Environment Agency at the Ministry of Waters and Environment by means of methods specified by the Ministry. The concentrations of damaging substances were automatically measured at every 60 min for SO2, NO2, NO, and at every 30 min for H2S, CH4, NMHC, CO, and NH3. The obtained results prove that the concentrations of NO, H2S, CH4 and NMHC exceed all limits. The quantity of gases is influenced by the variety peculiarities of the culture (the roots mass, the total bio-mass and the running metabolic processes).
18
Spiro, Peter J. "The Possibilities of Global Migration Law." AJIL Unbound 111 (2017): 3–7. http://dx.doi.org/10.1017/aju.2017.10.
Full textAbstract:
When I started teaching international law more than twenty years ago, it was still possible to be an international law generalist. In the U.S. legal academy, the likes of Henkin, Schachter, Franck, and McDougal covered the full range of public international law subjects. (Some even managed to stay on top of private international law, too.) Today, being an international law generalist is impractical; it's simply too difficult to keep current with the breadth of international law. From the scholar's perspective, it's a case of “be careful what you wish for.” A generalist international law orientation used to be possible because there was so little of it, both on the ground and in the scholarship. Those mid-century saplings—the various distinctive fields within international law—have grown to mature oaks, and expert knowledge of their many crevices and branches is beyond the capacity of any single observer. Not only does international law defy individual mastery, but the level of specialization now makes it difficult to talk across these different areas. My colleague in international criminal law might as well be a domestic family law person for purposes of professional points of connection. We both attend the ASIL Annual Meeting, but we no longer really speak the same language.
19
Immel, T. J., H. U. Frey, S. B. Mende, and E. Sagawa. "Global observations of the zonal drift speed of equatorial ionospheric plasma bubbles." Annales Geophysicae 22, no. 9 (September 23, 2004): 3099–107. http://dx.doi.org/10.5194/angeo-22-3099-2004.
Full textAbstract:
Abstract. Space-based measurements from an imager aboard the high-apogee NASA-IMAGE satellite allows for global-scale observations of nightside ionospheric densities and structure. Such a view cannot be provided by imagers in near-Earth orbit or based on the ground. The IMAGE Spectroscopic Imager (SI) isolates the Far-ultraviolet (FUV) O I 135.6nm emission which is produced through radiative recombination of O+. These observations clearly show the distribution of FUV emissions of the equatorial airglow bands over the range of local times between the evening terminator to points well after midnight. Determination of plasma drift speeds in these local time sectors is performed by identification and subsequent tracking of localized depressions in the FUV emissions. This determination is made for nearly 200 plasma bubbles in the March-May period of 2002. Important findings of this study include (1) an unambiguous association between Dst and zonal plasma drift speeds, and (2) a longitudinal dependence of the zonal plasma drift speeds, with a peak around the Indian sector. The first effect is attributed to penetrating ring current electric fields, while the second is apparently due to a longitudinal variability in the vertical polarization electric fields that directly affects the zonal plasma drift speeds.
20
Farolfi, Gregorio, Aldo Piombino, and Filippo Catani. "Fusion of GNSS and Satellite Radar Interferometry: Determination of 3D Fine-Scale Map of Present-Day Surface Displacements in Italy as Expressions of Geodynamic Processes." Remote Sensing 11, no. 4 (February 15, 2019): 394. http://dx.doi.org/10.3390/rs11040394.
Full textAbstract:
We present a detailed map of ground movement in Italy derived from the combination of the Global Navigation Satellite System (GNSS) and Satellite Synthetic Aperture Radar (SAR) interferometry. These techniques are two of the most used space geodetic techniques to study Earth surface deformation. The above techniques provide displacements with respect to different components of the ground point position; GNSSs use the geocentric International Terrestrial Reference System 1989 (ITRS89), whereas the satellite SAR interferometry components are identified by the Lines of Sight (LOSs) between a satellite and ground points. Moreover, SAR interferometry is a differential technique, and for that reason, displacements have no absolute reference datum. We performed datum alignment of InSAR products using precise velocity fields derived from GNSS permanent stations. The result is a coherent ground velocity field with detailed boundaries of velocity patterns that provide new information about the complex geodynamics involved on the Italian peninsula and about local movements.
21
Beaudot, W. H. A. "A Neuromorphic Recurrent Model for Figure-Ground Segregation of Coherent Motion." Perception 26, no. 1_suppl (August 1997): 84. http://dx.doi.org/10.1068/v970195.
Full textAbstract:
A neuromorphic model of the retino-cortical motion processing stream is proposed which incorporates both feedforward and feedback mechanisms. The feedforward stream consists of motion integration from the retina to the MT area. Retinal spatiotemporal filtering provides X-like and Y-like visual inputs with band-pass characteristics to the V1 area (Beaudot, 1996 Perception25 Supplement, 30 – 31). V1 direction-selective cells respond to local motion resulting from nonlinear interactions between retinal inputs. MT direction-selective cells respond to global motion resulting from spatial convergence and temporal integration of V1 signals. This feedforward stream provides a fine representation of local motion in V1 and a coarse representation of global motion in MT. However, it is unable to deal with the aperture problem. Solving this problem requires the adjunction of local constraints related to both smoothness and discontinuity of coherent motion, as well as some minimisation techniques to obtain the optimal solution. We propose a plausible neural substrate for this computation by incorporating excitatory intracortical feedbacks in V1 and their modulation by reciprocal connections from MT. The underlying enhancement or depression of V1 responses according to the strength of MT responses reflects changes in the spatiotemporal properties of the V1 receptive fields. This mechanism induces a dynamic competition between local and global motion representations in V1. On convergence of these dynamics, responses of V1 direction-selective cells provide a fine representation of ‘true’ motion, thus solving the aperture problem and allowing a figure - ground segregation based on coherent motion. The model is compatible with recent anatomical, physiological, and psychophysical evidence [Bullier et al, 1996 Journal de Physiologie (Paris)90 217 – 220].
22
Goodbrake, Christian, Alain Goriely, and Arash Yavari. "The mathematical foundations of anelasticity: existence of smooth global intermediate configurations." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 477, no. 2245 (January 2021): 20200462. http://dx.doi.org/10.1098/rspa.2020.0462.
Full textAbstract:
A central tool of nonlinear anelasticity is the multiplicative decomposition of the deformation tensor that assumes that the deformation gradient can be decomposed as a product of an elastic and an anelastic tensor. It is usually justified by the existence of an intermediate configuration. Yet, this configuration cannot exist in Euclidean space, in general, and the mathematical basis for this assumption is on unsatisfactory ground. Here, we derive a sufficient condition for the existence of global intermediate configurations, starting from a multiplicative decomposition of the deformation gradient. We show that these global configurations are unique up to isometry. We examine the result of isometrically embedding these configurations in higher-dimensional Euclidean space, and construct multiplicative decompositions of the deformation gradient reflecting these embeddings. As an example, for a family of radially symmetric deformations, we construct isometric embeddings of the resulting intermediate configurations, and compute the residual stress fields explicitly.
23
Khorramdel, Surur, Javad Shabahang, Raheleh Ahmadzadeh Ghavidel, and Abdollah Mollafilabi. "Evaluation of Carbon Sequestration and Global Warming Potential of Wheat in Khorasan-Razavi province." agriTECH 38, no. 3 (March 12, 2019): 330. http://dx.doi.org/10.22146/agritech.28430.
Full textAbstract:
In order to determine soil characteristics and above-ground and below-ground carbon sequestration potential of wheat, a systematic random sampling method was employed to select 5 samples from 50 fields situated in Khorasan-Razavi Province, Iran during 2015. The experimental design was a completely randomized design with three replications. The ash method was used to determine the carbon sequestration conversion coefficients in spikes, stems, leaves and roots. Then, greenhouse gases (such as CO2, N2O and CH4) emission were calculated using emission coefficients. The average organic carbon, total nitrogen, available phosphorus, available potassium, soil bulk density, pH and electrical conductivity were found to be 0.98%, 0.02%, 27.07 ppm, 341.32 ppm, 1.37 g.cm-3, 7.81 and 1.42 dS.m-1, respectively. The maximum (52.0%) and minimum (31.99%) conversion coefficients were related to spikes (seeds included) and roots, respectively. In addition, the total carbon sequestration was 8.25 t.ha-1 so that the maximum (4.28 t.ha-1) and minimum (0.35 t.ha-1) values were found in stems and roots, respectively. The total global warming potential (GWP) of wheat was recorded as 2377.86 kg CO2 –equiv. per ton of seed. The first contributing factor was nitrogen fertilizers, accounting for 1331.30 kg CO2 –equiv. per ton of seed.
24
Rayner, Nick A., Renate Auchmann, Janette Bessembinder, Stefan Brönnimann, Yuri Brugnara, Francesco Capponi, Laura Carrea, et al. "The EUSTACE Project: Delivering Global, Daily Information on Surface Air Temperature." Bulletin of the American Meteorological Society 101, no. 11 (November 1, 2020): E1924—E1947. http://dx.doi.org/10.1175/bams-d-19-0095.1.
Full textAbstract:
AbstractDay-to-day variations in surface air temperature affect society in many ways, but daily surface air temperature measurements are not available everywhere. Therefore, a global daily picture cannot be achieved with measurements made in situ alone and needs to incorporate estimates from satellite retrievals. This article presents the science developed in the EU Horizon 2020–funded EUSTACE project (2015–19, www.eustaceproject.org) to produce global and European multidecadal ensembles of daily analyses of surface air temperature complementary to those from dynamical reanalyses, integrating different ground-based and satellite-borne data types. Relationships between surface air temperature measurements and satellite-based estimates of surface skin temperature over all surfaces of Earth (land, ocean, ice, and lakes) are quantified. Information contained in the satellite retrievals then helps to estimate air temperature and create global fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place; this needs efficient statistical analysis methods to cope with the considerable data volumes. Daily fields are presented as ensembles to enable propagation of uncertainties through applications. Estimated temperatures and their uncertainties are evaluated against independent measurements and other surface temperature datasets. Achievements in the EUSTACE project have also included fundamental preparatory work useful to others, for example, gathering user requirements, identifying inhomogeneities in daily surface air temperature measurement series from weather stations, carefully quantifying uncertainties in satellite skin and air temperature estimates, exploring the interaction between air temperature and lakes, developing statistical models relevant to non-Gaussian variables, and methods for efficient computation.
25
Del Soldato, Matteo, Pierluigi Confuorto, Silvia Bianchini, Paolo Sbarra, and Nicola Casagli. "Review of Works Combining GNSS and InSAR in Europe." Remote Sensing 13, no. 9 (April 27, 2021): 1684. http://dx.doi.org/10.3390/rs13091684.
Full textAbstract:
The Global Navigation Satellite System (GNSS) and Synthetic Aperture Radar Interferometry (InSAR) can be combined to achieve different goals, owing to their main principles. Both enable the collection of information about ground deformation due to the differences of two consequent acquisitions. Their variable applications, even if strictly related to ground deformation and water vapor determination, have encouraged the scientific community to combine GNSS and InSAR data and their derivable products. In this work, more than 190 scientific contributions were collected spanning the whole European continent. The spatial and temporal distribution of such studies, as well as the distinction in different fields of application, were analyzed. Research in Italy, as the most represented nation, with 47 scientific contributions, has been dedicated to the spatial and temporal distribution of its studied phenomena. The state-of-the-art of the various applications of these two combined techniques can improve the knowledge of the scientific community and help in the further development of new approaches or additional applications in different fields. The demonstrated usefulness and versability of the combination of GNSS and InSAR remote sensing techniques for different purposes, as well as the availability of free data, EUREF and GMS (Ground Motion Service), and the possibility of overcoming some limitations of these techniques through their combination suggest an increasingly widespread approach.
26
Kobea, A. T., C. Amory-Mazaudier, J. M. Do, H. Lühr, E. Houngninou, J. Vassal, E. Blanc, and J. J. Curto. "Equatorial electrojet as part of the global circuit: a case-study from the IEEY." Annales Geophysicae 16, no. 6 (June 30, 1998): 698–710. http://dx.doi.org/10.1007/s00585-998-0698-1.
Full textAbstract:
Abstract. Geomagnetic storm-time variations often occur coherently at high latitude and the day-side dip equator where they affect the normal eastward Sq field. This paper presents an analysis of ground magnetic field and ionospheric electrodynamic data related to the geomagnetic storm which occured on 27 May 1993 during the International Equatorial Electrojet Year (IEEY) experiment. This storm-signature analysis on the auroral, mid-latitude and equatorial ground field and ionospheric electrodynamic data leads to the identification of a sensitive response of the equatorial electrojet (EEJ) to large-scale auroral return current: this response consists in a change of the eastward electric field during the pre-sunrise hours (0400-0600 UT) coherently to the high-, mid-, and equatorial-latitude H decrease and the disappearance of the EEJ irregularities between the time-interval 0800-0950 UT. Subsequent to the change in h'F during pre-sunrise hours, the observed foF2 increase revealed an enhancement of the equatorial ionization anomaly (EIA) caused by the high-latitude penetrating electric field. The strengthening of these irregularities attested by the Doppler frequency increase tracks the H component at the equator which undergoes a rapid increase around 0800 UT. The ∆H variations observed at the equator are the sum of the following components: SR, DP, DR, DCF and DT.Keywords. Equatorial electrojet · Magnetosphere-ionosphere interactions · Electric fields and currents · Auroral ionosphere · Ionospheric disturbances
27
Bedding, Timothy R., Allan S. Brun, Jørgen Christensen-Dalsgaard, Ashley Crouch, Peter De Cat, Raphael A. García, Laurent Gizon, et al. "Joint Discussion 17 Highlights of recent progress in the seismology of the Sun and Sun-like stars." Proceedings of the International Astronomical Union 2, no. 14 (August 2006): 491–516. http://dx.doi.org/10.1017/s1743921307011635.
Full textAbstract:
AbstractThe seismology and physics of localized structures beneath the surface of the Sun takes on a special significance with the completion in 2006 of a solar cycle of observations by the ground-based Global Oscillation Network Group (GONG) and by the instruments on board theSolar and Heliospheric Observatory(SOHO). Of course, the spatially unresolved Birmingham Solar Oscillation Network (BiSON) has been observing for even longer. At the same time, the testing of models of stellar structure moves into high gear with the extension of deep probes from the Sun to other solar-like stars and other multi-mode pulsators, with ever-improving observations made from the ground, the success of theMOSTsatellite, and the recently launchedCoRoTsatellite. Here we report the current state of the two closely related and rapidly developing fields of helio- and asteroseimology.
28
Wolford, Wendy. "From Pangaea to Partnership." Sociology of Development 1, no. 2 (2015): 2–24. http://dx.doi.org/10.1525/sod.2015.1.2.2.
Full textAbstract:
Over the past decade, the rise of what has been called the Global Land Grab suggests the return of rural development as a privileged (if problematic) site for accumulation, modernization, and growth. In this paper, I analyze a set of rural development efforts in Mozambique, a country seen by many as the potential heart of a new African food regime. I build a framework for understanding contemporary dynamics by drawing on the triple metaphor of fields: first, I build on the sociological concept of field as strategic social space; second, I bring together disparate disciplinary fields, including political economy, development, science and technology studies, and agrarian studies; and third, I situate the paper on fields as cultivated ground, the literal arena in and on which rural development takes place. The paper is narrated through four stories that illuminate the relationships and dynamics within and across different “strategic action fields.” These stories highlight the role of knowledge and power within distinct but related arenas of rural development and suggest the importance of seeing fields as in contestation even when they are not necessarily in conversation.
29
Wolford, Wendy. "From Pangaea to Partnership." Sociology of Development 1, no. 2 (2015): 210–32. http://dx.doi.org/10.1525/sod.2015.1.2.210.
Full textAbstract:
Over the past decade, the rise of what has been called the Global Land Grab suggests the return of rural development as a privileged (if problematic) site for accumulation, modernization, and growth. In this paper, I analyze a set of rural development efforts in Mozambique, a country seen by many as the potential heart of a new African food regime. I build a framework for understanding contemporary dynamics by drawing on the triple metaphor of fields: first, I build on the sociological concept of field as strategic social space; second, I bring together disparate disciplinary fields, including political economy, development, science and technology studies, and agrarian studies; and third, I situate the paper on fields as cultivated ground, the literal arena in and on which rural development takes place. The paper is narrated through four stories that illuminate the relationships and dynamics within and across different “strategic action fields.” These stories highlight the role of knowledge and power within distinct but related fields of rural development and suggest the importance of seeing them as in contestation even when they are not necessarily in conversation.
30
Broxton, Patrick D., Xubin Zeng, William Scheftic, and Peter A. Troch. "A MODIS-Based Global 1-km Maximum Green Vegetation Fraction Dataset." Journal of Applied Meteorology and Climatology 53, no. 8 (August 2014): 1996–2004. http://dx.doi.org/10.1175/jamc-d-13-0356.1.
Full textAbstract:
AbstractGlobal land-cover data are widely used in regional and global models because land cover influences land–atmosphere exchanges of water, energy, momentum, and carbon. Many models use data of maximum green vegetation fraction (MGVF) to describe vegetation abundance. MGVF products have been created in the past using different methods, but their validation with ground sites is difficult. Furthermore, uncertainty is introduced because many products use a single year of satellite data. In this study, a global 1-km MGVF product is developed on the basis of a “climatology” of data of Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index and land-cover type, which removes biases associated with unusual greenness and inaccurate land-cover classification for individual years. MGVF shows maximum annual variability from 2001 to 2012 for intermediate values of average MGVF, and the standard deviation of MGVF normalized by its mean value decreases nearly monotonically as MGVF increases. In addition, there are substantial differences between this climatology and MGVF data from the MODIS Continuous Fields (CF) Collection 3, which is currently used in the Community Land Model. Although the CF data only use 2001 MODIS data, many of these differences cannot be explained by usage of different years of data. In particular, MGVF as based on CF data is usually higher than that based on the MODIS climatology from this paper. It is difficult to judge which product is more realistic because of a lack of ground truth, but this new MGVF product is more consistent than the CF data with the MODIS leaf area index product (which is also used to describe vegetation abundance in models).
31
Greenslade, Diana J. M., and Ian R. Young. "The Impact of Altimeter Sampling Patterns on Estimates of Background Errors in a Global Wave Model." Journal of Atmospheric and Oceanic Technology 22, no. 12 (December 1, 2005): 1895–917. http://dx.doi.org/10.1175/jtech1811.1.
Full textAbstract:
Abstract One of the main limitations to current wave data assimilation systems is the lack of an accurate representation of the structure of the background errors. One method that may be used to determine background errors is the observational method of Hollingsworth and Lönnberg. The observational method considers correlations of the differences between observations and the background. For the case of significant wave height (SWH), potential observations come from satellite altimeters. In this work, the effect of the irregular sampling pattern of the satellite on estimates of background errors is examined. This is achieved by using anomalies from a 3-month mean as a proxy for model errors. A set of anomaly correlations is constructed from modeled wave fields. The isotropic length scales of the anomaly correlations are found to vary considerably over the globe. In addition, the anomaly correlations are found to be significantly anisotropic. The modeled wave fields are then sampled at simulated altimeter observation locations, and the anomaly correlations are recalculated from the simulated altimeter data. The results are compared to the original anomaly correlations. It is found that, in general, the simulated altimeter data can capture most of the geographic and seasonal variability in the isotropic anomaly correlation length scale. The best estimates of the isotropic length scales come from a method in which correlations are calculated between pairs of observations from prior and subsequent ground tracks, in addition to along-track pairs of observations. This method was found to underestimate the isotropic anomaly correlation length scale by approximately 10%. The simulated altimeter data were not so successful in producing realistic anisotropic correlation functions. This is because of the lack of information in the zonal direction in the simulated altimeter data. However, examination of correlations along ascending and descending ground tracks separately can provide some indication of the areas on the globe for which the anomaly correlations are more anisotropic than others.
32
Kountouriotis, Georgios K., Callum D. Mole, Natasha Merat, and Richard M. Wilkie. "The need for speed: global optic flow speed influences steering." Royal Society Open Science 3, no. 5 (May 2016): 160096. http://dx.doi.org/10.1098/rsos.160096.
Full textAbstract:
How do animals follow demarcated paths? Different species are sensitive to optic flow and one control solution is to maintain the balance of flow symmetry across visual fields; however, it is unclear whether animals are sensitive to changes in asymmetries when steering along curved paths. Flow asymmetries can alter the global properties of flow (i.e. flow speed) which may also influence steering control. We tested humans steering curved paths in a virtual environment. The scene was manipulated so that the ground plane to either side of the demarcated path produced larger or smaller asymmetries in optic flow. Independent of asymmetries and the locomotor speed, the scene properties were altered to produce either faster or slower globally averaged flow speeds. Results showed that rather than being influenced by changes in flow asymmetry, steering responded to global flow speed. We conclude that the human brain performs global averaging of flow speed from across the scene and uses this signal as an input for steering control. This finding is surprising since the demarcated path provided sufficient information to steer, whereas global flow speed (by itself) did not. To explain these findings, existing models of steering must be modified to include a new perceptual variable: namely global optic flow speed.
33
Bonnavion, Guillaume, and Olivier Cadot. "Unstable wake dynamics of rectangular flat-backed bluff bodies with inclination and ground proximity." Journal of Fluid Mechanics 854 (September 6, 2018): 196–232. http://dx.doi.org/10.1017/jfm.2018.630.
Full textAbstract:
The paper investigates experimentally the global wake dynamics of a simplified three-dimensional ground vehicle at a Reynolds number of $Re\simeq 4.0\times 10^{5}$. The after-body has a blunt rectangular trailing edge leading to a massive flow separation. Both the inclination (yaw and pitch angles) and the distance to the ground (ground clearance) are accurately adjustable. Two different aspect ratios of the rectangular base are considered; wider than it is tall (minor axis perpendicular to the ground) and taller than it is wide (major axis perpendicular to the ground). Measurements of the spatial distribution of the pressure at the base and velocity fields in the wake are used as topological indicators of the flow. Sensitivity analyses of the base pressure gradient expressed in polar form (modulus and phase) varying ground clearance, yaw and pitch are performed. Above a critical ground clearance and whatever the inclination is, the modulus is always found to be large due to the permanent static symmetry-breaking instability, and slightly smaller when aligned with the minor axis of the base rather than when aligned with the major axis. The instability can be characterized with a unique wake mode, quantified by this modulus (asymmetry strength) and a phase (wake orientation) which is the key ingredient of the global wake dynamics. An additional deep rear cavity that suppresses the static instability allows a basic flow to be characterized. It is shown that both the inclination and the ground clearance constrain the phase dynamics of the unstable wake in such way that the component of the pressure gradient aligned with the minor axis of the rectangular base equals that of the basic flow. Meanwhile, the other component related to the major axis adjusts to preserve the large modulus imposed by the instability. In most cases, the dynamics explores only two possible opposite values of the component along the major axis. Their respective probability depends on the geometrical environment of the wake: base shape, body inclination, ground proximity and body supports. An expression for the lateral force coefficients taking into account the wake instability is proposed.
34
Liu, Lou, Zhang, Huang, Zhou, and Zhang. "On the Study of Influences of Different Factors on the Rapid Tropospheric Tomography." Remote Sensing 11, no. 13 (June 28, 2019): 1545. http://dx.doi.org/10.3390/rs11131545.
Full textAbstract:
A rapid tropospheric tomography system was developed by using algebraicreconstruction technique. Influences of different factors on the tomographic results, including theground meteorological data, the multi-Global Navigation Satellite System (GNSS) observations, theground station distribution and the tomographic horizontal resolution, were systematicallyinvestigated. In order to exclude the impacts from discrepancies of water vapor informationbetween input observations and references on the tomographic results, the latest reanalysisproducts, ERA5, which were taken as references for result evaluations, were used to simulate slantwet delay (SWD) observations at GNSS stations. Besides, the slant delays derived from GNSSprocessing were also used to evaluate the reliability of simulated observations. Tomography resultsshow that the input both SWD and ground meteorological data could improve the tomographicresults where SWD mainly improve the results at middle layers (500 to 5000m, namely 2 to 16 layer)and ground meteorological data could improve the humidity fields at bottom layers further (0 to500m, namely 0 to 2 layer). Compared to the usage of Global Positioning System (GPS) only SWD,the inclusion of multi-GNSS SWD does not significantly improve the tomographic results at alllayers due to the almost unchanged dispersion of puncture points of GNSS signals. However,increases in the ground GNSS stations can benefit the tomography, with improvements of morethan 10% at bottom and middle layers. Higher tomographic horizontal resolution can furtherslightly improve the tomographic results (about 3-6% from 0.5 to 0.25 degrees), which, however,will also increase the computational burden at the same time.
35
Konecky, Bronwen L., Nicholas P. McKay, Olga V. Churakova (Sidorova), Laia Comas-Bru, Emilie P. Dassié, Kristine L. DeLong, Georgina M. Falster, et al. "The Iso2k database: a global compilation of paleo-<i>δ</i><sup>18</sup>O and <i>δ</i><sup>2</sup>H records to aid understanding of Common Era climate." Earth System Science Data 12, no. 3 (September 23, 2020): 2261–88. http://dx.doi.org/10.5194/essd-12-2261-2020.
Full textAbstract:
Abstract. Reconstructions of global hydroclimate during the Common Era (CE; the past ∼2000 years) are important for providing context for current and future global environmental change. Stable isotope ratios in water are quantitative indicators of hydroclimate on regional to global scales, and these signals are encoded in a wide range of natural geologic archives. Here we present the Iso2k database, a global compilation of previously published datasets from a variety of natural archives that record the stable oxygen (δ18O) or hydrogen (δ2H) isotopic compositions of environmental waters, which reflect hydroclimate changes over the CE. The Iso2k database contains 759 isotope records from the terrestrial and marine realms, including glacier and ground ice (210); speleothems (68); corals, sclerosponges, and mollusks (143); wood (81); lake sediments and other terrestrial sediments (e.g., loess) (158); and marine sediments (99). Individual datasets have temporal resolutions ranging from sub-annual to centennial and include chronological data where available. A fundamental feature of the database is its comprehensive metadata, which will assist both experts and nonexperts in the interpretation of each record and in data synthesis. Key metadata fields have standardized vocabularies to facilitate comparisons across diverse archives and with climate-model-simulated fields. This is the first global-scale collection of water isotope proxy records from multiple types of geological and biological archives. It is suitable for evaluating hydroclimate processes through time and space using large-scale synthesis, model–data intercomparison and (paleo)data assimilation. The Iso2k database is available for download at https://doi.org/10.25921/57j8-vs18 (Konecky and McKay, 2020) and is also accessible via the NOAA/WDS Paleo Data landing page: https://www.ncdc.noaa.gov/paleo/study/29593 (last access: 30 July 2020).
36
Newman, Lena. "Nicholas S. Paliewicz and Marouf Hasian Jr. The Securitization of Memorial Space: Rhetoric and Public Memory." RBM: A Journal of Rare Books, Manuscripts, and Cultural Heritage 21, no. 1 (May 29, 2020): 42. http://dx.doi.org/10.5860/rbm.21.1.42.
Full textAbstract:
In The Securitization of Memorial Space: Rhetoric and Public Memory, Nicholas S. Paliewicz and Marouf Hasian Jr. train a darkly analytical lens on New York City’s Ground Zero in the aftermath of September 11, 2001 terrorist attacks on the World Trade Center, and the debate around how to memorialize the events of that day. The authors explore how various objects at Ground Zero were infused with political meaning and deployed like weapons by myriad actors in both the smaller battle for control of the National September 11 Memorial and Museum and the larger Global War on Terror. Hasian and Paliewicz are writing from backgrounds in rhetorical and critical security studies, and at times their writing can be a little opaque to those not fluent in the vocabulary of those fields. The authors also describe their approach as “object oriented,” a methodology that should sound familiar to anyone working in special collections today (23).
37
Barton, Ian J. "Comparison of In Situ and Satellite-Derived Sea Surface Temperatures in the Gulf of Carpentaria." Journal of Atmospheric and Oceanic Technology 24, no. 10 (October 1, 2007): 1773–84. http://dx.doi.org/10.1175/jtech2084.1.
Full textAbstract:
Abstract During 30 days in May and June 2003, the R/V Southern Surveyor was operating in the Gulf of Carpentaria, northern Australia. Measurements of sea surface temperature (SST) were made with an accurate single-channel infrared radiometer as well as with the ship’s thermosalinograph. These ship-based measurements have been used to assess the quality of the SST derived from nine satellite-borne instruments. The satellite dataset compiled during this period also allows the intercomparison of satellite-derived SST fields in areas not covered by the ship’s track. An assessment of the SST quality from each satellite instrument is presented, and suggestions for blending ground and satellite measurements into a single product are made. These suggestions are directly applicable to the international Global Ocean Data Assimilation Experiment (GODAE) High Resolution SST Pilot Project (GHRSST-PP) that is currently developing an operational system to provide 6-hourly global fields of SST at a spatial resolution close to 10 km. The paper demonstrates how the Diagnostic Datasets (DDSs) and Matchup Database (MDB) of the GHRSST-PP can be used to monitor the quality of individual and blended SST datasets. Recommendations for future satellite missions that are critical to the long-term generation of accurate blended SST datasets are included.
38
McGrath, Justin M., Amy M. Betzelberger, Shaowen Wang, Eric Shook, Xin-Guang Zhu, Stephen P. Long, and Elizabeth A. Ainsworth. "An analysis of ozone damage to historical maize and soybean yields in the United States." Proceedings of the National Academy of Sciences 112, no. 46 (November 2, 2015): 14390–95. http://dx.doi.org/10.1073/pnas.1509777112.
Full textAbstract:
Numerous controlled experiments find that elevated ground-level ozone concentrations ([O3]) damage crops and reduce yield. There have been no estimates of the actual yield losses in the field in the United States from [O3], even though such estimates would be valuable for projections of future food production and for cost–benefit analyses of reducing ground-level [O3]. Regression analysis of historical yield, climate, and [O3] data for the United States were used to determine the loss of production due to O3 for maize (Zea mays) and soybean (Glycine max) from 1980 to 2011, showing that over that period production of rain-fed fields of soybean and maize were reduced by roughly 5% and 10%, respectively, costing approximately $9 billion annually. Maize, thought to be inherently resistant to O3, was at least as sensitive as soybean to O3 damage. Overcoming this yield loss with improved emission controls or more tolerant germplasm could substantially increase world food and feed supply at a time when a global yield jump is urgently needed.
39
Margulis, Steven A., Dara Entekhabi, and Dennis McLaughlin. "Spatiotemporal Disaggregation of Remotely Sensed Precipitation for Ensemble Hydrologic Modeling and Data Assimilation." Journal of Hydrometeorology 7, no. 3 (June 1, 2006): 511–33. http://dx.doi.org/10.1175/jhm492.1.
Full textAbstract:
Abstract Historically, estimates of precipitation for hydrologic applications have largely been obtained using ground-based rain gauges despite the fact that they can contain significant measurement and sampling errors. Remotely sensed precipitation products provide the ability to overcome spatial coverage limitations, but the direct use of these products generally suffers from their relatively coarse spatial and temporal resolution and inherent retrieval errors. A simple ensemble-based disaggregation scheme is proposed as a general framework for using remotely sensed precipitation data in hydrologic applications. The scheme generates fine-scale precipitation realizations that are conditioned on large-scale precipitation measurements. The ensemble approach allows for uncertainty related to the complex error characteristics of the remotely sensed precipitation (undetected events, nonzero false alarm rate, etc.) to be taken into account. The methodology is applied through several synthetic experiments over the southern Great Plains using the Global Precipitation Climatology Project 1° daily (GPCP-1DD) product. The scheme is shown to reasonably capture the land-surface-forcing variability and propagate this uncertainty to the estimation of soil moisture and land surface flux fields at fine scales. The ensemble results outperform a case using sparse ground-based forcing. Additionally, the ensemble nature of the framework allows for simply merging the open-loop soil moisture estimation scheme with modern data assimilation techniques like the ensemble Kalman filter. Results show that estimation of the soil moisture and surface flux fields are further improved through the assimilation of coarse-scale microwave radiobrightness observations.
40
Gómez-Enri, J., C. P. Gommenginger, M. A. Srokosz, P. G. Challenor, and J. Benveniste. "Measuring Global Ocean Wave Skewness by Retracking RA-2 Envisat Waveforms." Journal of Atmospheric and Oceanic Technology 24, no. 6 (June 2007): 1102–16. http://dx.doi.org/10.1175/jtech2014.1.
Full textAbstract:
For early satellite altimeters, the retrieval of geophysical information (e.g., range, significant wave height) from altimeter ocean waveforms was performed on board the satellite, but this was restricted by computational constraints that limited how much processing could be performed. Today, ground-based retracking of averaged waveforms transmitted to the earth is less restrictive, especially with respect to assumptions about the statistics of ocean waves. In this paper, a theoretical maximum likelihood estimation (MLE) ocean waveform retracker is applied tothe Envisat Radar Altimeter system (RA-2) 18-Hz averaged waveforms under both linear (Gaussian) and nonlinear ocean wave statistics assumptions, to determine whether ocean wave skewness can be sensibly retrieved from Envisat RA-2 waveforms. Results from the MLE retracker used in nonlinear mode provide the first estimates of global ocean wave skewness based on RA-2 Envisat averaged waveforms. These results show for the first time geographically coherent skewness fields and confirm the notion that large values of skewness occur primarily in regions of large significant wave height. Results from the MLE retracker run in linear and nonlinear modes are compared with each other and with the RA-2 Level 2 Sensor Geophysical Data Records (SGDR) products to evaluate the impact of retrieving skewness on other geophysical parameters. Good agreement is obtained between the linear and nonlinear MLE results for both significant wave height and epoch (range), except in areas of high-wave-height conditions.
41
Roustan, Y., and M. Bocquet. "Inverse modelling for mercury over Europe." Atmospheric Chemistry and Physics 6, no. 10 (July 24, 2006): 3085–98. http://dx.doi.org/10.5194/acp-6-3085-2006.
Full textAbstract:
Abstract. The fate and transport of mercury over Europe is studied using a regional Eulerian transport model. Because gaseous elemental mercury is a long-lived species in the atmosphere, boundary conditions must be properly taken into account. Ground measurements of gaseous mercury are very sensitive to the uncertainties attached to those forcing conditions. Inverse modelling can help to constrain the forcing fields and help to improve the predicted mercury concentrations. More generally, it allows to reduce the weaknesses of a regional model against a global or hemispherical model for such diffuse trace constituent. Adjoint techniques are employed to relate rigorously and explicitly the measurements to the forcing fields. This way, the inverse problem is clearly defined. Using EMEP measurements of gaseous mercury and performing the inversions, it is shown that boundary conditions can be improved significantly as well as the forecast concentrations. Using inverse modelling to improve the emission inventory is however much more difficult. Indeed, there are currently not enough mercury monitoring stations, and they are located far away from the center of Europe.
42
Roustan, Y., and M. Bocquet. "Inverse modelling for mercury over Europe." Atmospheric Chemistry and Physics Discussions 6, no. 1 (January 30, 2006): 795–838. http://dx.doi.org/10.5194/acpd-6-795-2006.
Full textAbstract:
Abstract. The fate and transport of mercury over Europe is studied using a regional Eulerian transport model. Because gaseous elemental mercury is a long-lived species in the atmosphere, boundary conditions must be properly taken into account. Ground measurements of gaseous mercury are very sensitive to the uncertainties attached to those forcing conditions. Inverse modelling can help to constrain the forcing fields and help to improve the predicted mercury concentrations. More generally, it allows to reduce the weaknesses of a regional model against a global or hemispherical model for such diffuse trace constituent. Adjoint techniques are employed to relate rigorously and explicitly the measurements to the forcing fields. This way, the inverse problem is clearly defined. Using EMEP measurements of gaseous mercury and performing the inversions, it is shown that boundary conditions can be improved significantly as well as the forecast concentrations. Using inverse modelling to improve the emission inventory is however much more difficult since there are currently not enough mercury monitoring stations, and their location far from Europe centre.
43
Bogart, R. S., L. A. Discher De Sá, I. González Hernández, J. Patrón Recio, D. A. Haber, J. Toomre, F. Hill, E. J. Rhodes, and Y. Xue. "Plane-wave analysis of SOI data." Symposium - International Astronomical Union 181 (1997): 111–18. http://dx.doi.org/10.1017/s0074180900061076.
Full textAbstract:
The unprecedented combination of spatial resolution and stability achieved by the Solar Oscillations Investigation/Michelson Doppler Imager on SOHO has opened up new opportunities for the analysis of solar surface oscillations of high spatial frequencies. In this regime the oscillations are essentially plane waves, amenable to the techniques of ring-diagram analysis of their three-dimensional power spectra. This approach holds the promise of measuring fluid motions and possibly magnetic fields in spatially-resolved structures within the uppermost levels of the convective envelope, a region unresolved by the global modes. Atmospheric g-modes trapped above the photosphere may also be detectable. We review the first results of plane-wave analysis of various types of SOI data and comparisons with the analyses of comparable ground-based datasets.
44
Allred, Barry, DeBonne Wishart, Luis Martinez, Harry Schomberg, Steven Mirsky, George Meyers, John Elliott, and Christine Charyton. "Delineation of Agricultural Drainage Pipe Patterns Using Ground Penetrating Radar Integrated with a Real-Time Kinematic Global Navigation Satellite System." Agriculture 8, no. 11 (October 24, 2018): 167. http://dx.doi.org/10.3390/agriculture8110167.
Full textAbstract:
Better methods are needed for mapping agricultural drainage pipe systems. Prior research on small test plots indicates that ground penetrating radar (GPR) is oftentimes capable of detecting buried drainage pipes; however, the feasibility of employing this geophysical technique in larger field areas has not been adequately evaluated. Ground penetrating radar integrated with a Real-Time Kinematic (RTK) Global Navigation Satellite System (GNSS) may be an effective and efficient means of mapping drain lines within agricultural fields. Therefore, GPR-RTK/GNSS was tested in three agricultural settings; with Site 1 and Site 2 located in Beltsville, MD, USA and Site 3 near Columbus, OH, USA. Soils at the three sites ranged from silty clay loam to loamy sand. A GPR unit with 250 MHz antennas was used to detect drainage pipes, and at Sites 1 and 2, a physical GNSS base station was utilized, while a virtual base station was employed at Site 3. The GPR-RTK/GNSS configurations used in this study delineated a complex rectangular drainage pipe system at Site 1, with one set of drainage pipes oriented southwest-northeast and a second oriented southeast-northwest. At Site 2, a herringbone drain line pattern was outlined, and at Site 3, random drain lines were found. When integrated with RTK/GNSS, spiral or serpentine GPR transects (or spiral/serpentine segments of a GPR transects) were utilized to provide insight on drain line directional trends. Consequently, given suitable field conditions, GPR integrated with RTK/GNSS can be a valuable tool for farmers and drainage contractors needing to map subsurface drainage systems.
45
Trebs, I., B. Bohn, C. Ammann, U. Rummel, M. Blumthaler, R. Koenigstedt, F. X. Meixner, S. Fan, and M. O. Andreae. "Relationship between the NO<sub>2</sub> photolysis frequency and the solar global irradiance." Atmospheric Measurement Techniques Discussions 2, no. 4 (July 13, 2009): 1537–73. http://dx.doi.org/10.5194/amtd-2-1537-2009.
Full textAbstract:
Abstract. Representative values of the atmospheric NO2 photolysis frequency, (j(NO2)), are required for the adequate calculation and interpretation of NO and NO2 concentrations and exchange fluxes near the surface. Direct measurements of j(NO2) at ground level are often not available in field studies. In most cases, modeling approaches involving complex radiative transfer calculations are used to estimate j(NO2) and other photolysis frequencies for air chemistry studies. However, important input parameters for accurate modeling are often missing, most importantly with regard to the radiative effects of clouds. On the other hand, solar global irradiance ("global radiation", G) is nowadays measured as a standard parameter in most field experiments and in many meteorological observation networks around the world. A linear relationship between j(NO2) and G was reported in previous studies and has been used to estimate j(NO2) from G in the past 30 years. We have measured j(NO2) using spectro- or filter radiometers and G using pyranometers side-by-side at several field sites. Our results cover a solar zenith angle range of 0–90°, and are based on nine field campaigns in temperate, subtropical and tropical environments during the period 1994–2008. We show that a second-order polynomial function (intercept=0): j(NO2)=(1+α)×(B1×G+B2×G2), with α defined as the site-dependent UV-A surface albedo and the polynomial coefficients (including uncertainty ranges): B1=(1.47±0.03)×10−5 W−1 m2 s−1 and B2=(−4.84±0.31)×10−9 W−2 m4 s−1 can be used to estimate ground-level j(NO2) directly from G, independent of solar zenith angle under all atmospheric conditions. The absolute j(NO2)↓ residual of the empirical function is ±6×10−4 s−1 (95.45% confidence level). The relationship is valid for sites below 800 m a.s.l. and under low background albedo conditions. It is not valid in alpine regions, above snow or ice and sandy or dry soil surfaces. Our function can be applied to estimate chemical life times of the NO2 molecule with respect to photolysis, and is useful for surface-atmosphere exchange and photochemistry studies close to the ground, e.g., above fields with short vegetation and above forest canopies.
46
Langley, Paul. "The folds of social finance: Making markets, remaking the social." Environment and Planning A: Economy and Space 52, no. 1 (January 16, 2018): 130–47. http://dx.doi.org/10.1177/0308518x17752682.
Full textAbstract:
The global financial crisis acted as a spur to ‘social finance’, a loose grouping of markets demarcated on the grounds of their ostensible social purpose. This article’s critical analysis of social finance contributes to cultural economy research into marketization processes in economic geography and allied fields. First, responding to calls for greater attention to be given to heterogeneous and variegated market-making processes ‘on the ground’, social finance is analysed as a relatively discrete and hybrid modality of marketization that makes possible the valuation and capitalization of the social economy to address collective social problems. Second, moving beyond topographical accounts that understand geographies of marketization as ‘taking place’ through the outward expansion of the market’s imagined boundaries, Gilles Deleuze’s concept of ‘the fold’ is elaborated upon to develop a topological analysis of the spatial constitution of social finance markets. The folds of social finance are seams of inflection, entanglements where the social utility typically lacking from mainstream finance is variously spliced and stitched into marketization processes. In social finance markets-in-the-making, ‘the social’ is also shown to be remade as an array of thoroughly liberal associations and subjectivities that are, at once, pluralist, ethical and entrepreneurial.
47
Vontrat-Reberac, A., J. C. Cerisier, N. Sato, and M. Lester. "Noon ionospheric signatures of a sudden commencement following a solar wind pressure pulse." Annales Geophysicae 20, no. 5 (May 31, 2002): 639–45. http://dx.doi.org/10.5194/angeo-20-639-2002.
Full textAbstract:
Abstract. Using experimental data from the Cutlass Super-DARN HF radars and from a subset of ground magnetometers of the IMAGE Scandinavian chain, the response of the ionosphere in the noon sector to a solar wind pressure increase is studied. The emphasis is on the signature of the convection vortices and of the Hall currents that are associated with the pair of opposite parallel currents flowing along the morning and afternoon high-latitude magnetic field lines. We show that the sudden commencement is characterised by an equatorward convection, immediately followed (within less than 3 min) by a strong poleward plasma motion. These results are shown to agree qualitatively with the global model of sudden commencement of Araki (1994).Key words. Ionosphere (plasma convection; electric fields and currents) – Magnetospheric physics (solar wind-magnetosphere interactions)
48
Ménégoz, M., D. Salas y Melia, M. Legrand, H. Teyssèdre, M. Michou, V.-H. Peuch, M. Martet, B. Josse, and I. Dombrowski-Etchevers. "Equilibrium of sinks and sources of sulphate over Europe: comparison between a six-year simulation and EMEP observations." Atmospheric Chemistry and Physics Discussions 9, no. 1 (February 12, 2009): 4381–415. http://dx.doi.org/10.5194/acpd-9-4381-2009.
Full textAbstract:
Abstract. Sulphate distributions were simulated with a global chemistry transport model. A chemical scheme describing the sulphur cycle and the parameterisations of the main sinks for sulphate aerosols were included in the model. A six-year simulation was conducted from the years 2000 to 2005, driven by the ECMWF operational analyses. Emissions come from an inventory representative of the year 2000. This paper focuses on the analysis of the sulphate sinks and sources over Europe for the entire period of simulation. The Sulphate burden shows a marked annual cycle, which is the result of the annual variations of the aqueous and gaseous chemistry. Sulphate columns can vary regionally by 100% between different years, due to meteorological conditions, driving chemistry, transport and wet deposition of sulphate aerosols. Sulphate ground concentrations, scavenging fluxes and precipitation modelled were compared with observations. The model represents quite well sulphate fields over Europe, but has a general tendency to overestimate sulphate ground concentrations, in particular over Northern Europe. We assume that it is linked to the representation of the scavenging fluxes, which are underestimated. We suggest that uncertainties in modelled precipitation explain only partially the underestimation of the scavenging fluxes in the model.
49
Douglass, Anne R., Susan E. Strahan, Luke D. Oman, and Richard S. Stolarski. "Multi-decadal records of stratospheric composition and their relationship to stratospheric circulation change." Atmospheric Chemistry and Physics 17, no. 19 (October 12, 2017): 12081–96. http://dx.doi.org/10.5194/acp-17-12081-2017.
Full textAbstract:
Abstract. Constituent evolution for 1990–2015 simulated using the Global Modeling Initiative chemistry and transport model driven by meteorological fields from the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) is compared with three sources of observations: ground-based column measurements of HNO3 and HCl from two stations in the Network for the Detection of Atmospheric Composition Change (NDACC, ∼ 1990–ongoing), profiles of CH4 from the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS, 1992–2005), and profiles of N2O from the Microwave Limb Sounder on the Earth Observing System satellite Aura (2005–ongoing). The differences between observed and simulated values are shown to be time dependent, with better agreement after ∼ 2000 compared with the prior decade. Furthermore, the differences between observed and simulated HNO3 and HCl columns are shown to be correlated with each other, suggesting that issues with the simulated transport and mixing cause the differences during the 1990s and that these issues are less important during the later years. Because the simulated fields are related to mean age in the lower stratosphere, we use these comparisons to evaluate the time dependence of mean age. The ongoing NDACC column observations provide critical information necessary to substantiate trends in mean age obtained using fields from MERRA-2 or any other reanalysis products.
50
Murray, Jessica R., Noel Bartlow, Yehuda Bock, Benjamin A. Brooks, James Foster, Jeffrey Freymueller, William C. Hammond, et al. "Regional Global Navigation Satellite System Networks for Crustal Deformation Monitoring." Seismological Research Letters 91, no. 2A (March 1, 2019): 552–72. http://dx.doi.org/10.1785/0220190113.
Full textAbstract:
Abstract Regional networks of Global Navigation Satellite System (GNSS) stations cover seismically and volcanically active areas throughout the United States. Data from these networks have been used to produce high-precision, three-component velocity fields covering broad geographic regions as well as position time series that track time-varying crustal deformation. This information has contributed to assessing interseismic strain accumulation and related seismic hazard, revealed previously unknown occurrences of aseismic fault slip, constrained coseismic slip estimates, and enabled monitoring of volcanic unrest and postseismic deformation. In addition, real-time GNSS data are now widely available. Such observations proved invaluable for tracking the rapidly evolving eruption of Kīlauea in 2018. Real-time earthquake source modeling using GNSS data is being incorporated into tsunami warning systems, and a vigorous research effort is focused on quantifying the contribution that real-time GNSS can make to improve earthquake early warnings as part of the Advanced National Seismic System ShakeAlert system. Real-time GNSS data can also aid in the tracking of ionospheric disturbances and precipitable water vapor for weather forecasting. Although regional GNSS and seismic networks generally have been established independently, their spatial footprints often overlap, and in some cases the same institution operates both types of networks. Further integration of GNSS and seismic networks would promote joint use of the two data types to better characterize earthquake sources and ground motion as well as offer opportunities for more efficient network operations. Looking ahead, upgrading network stations to leverage new GNSS technology could enable more precise positioning and robust real-time operations. New computational approaches such as machine learning have the potential to enable full utilization of the large amounts of data generated by continuous GNSS networks. Development of seafloor Global Positioning System-acoustic networks would provide unique information for fundamental and applied research on subduction zone seismic hazard and, potentially, monitoring.