124,612 research outputs found
Coupled land surface and radiative transfer models for the analysis of passive microwave satellite observations
No full textSoil moisture is one of the key variables controlling the water and energy exchanges between
Earth’s surface and the atmosphere. Therefore, remote sensing based soil moisture
information has potential applications in many disciplines. Besides numerical weather
forecasting and climate research these include agriculture and hydrologic applications like
flood and drought forecasting.
The first satellite specifically designed to deliver operational soil moisture products, SMOS
(Soil Moisture and Ocean Salinity), was launched 2009 by the European Space Agency
(ESA). SMOS is a passive microwave radiometer working in the L-band of the microwave
domain, corresponding to a frequency of roughly 1.4 GHz and relies on a new concept. The
microwave radiation emitted by the Earth’s surface is measured as brightness temperatures in
several look angles. A radiative transfer model is used in an inversion algorithm to retrieve
soil moisture and vegetation optical depth, a measure for the vegetation attenuation of the
soil’s microwave emission.
For the application of passive microwave remote sensing products a proper validation and
uncertainty assessment is essential. As these sensors have typical spatial resolutions in the
order of 40 – 50 km, a validation that relies solely on ground measurements is costly and
labour intensive. Here, environmental modelling can make a valuable contribution.
Therefore the present thesis concentrates on the question which contribution coupled land
surface and radiative transfer models can make to the validation and analysis of passive
microwave remote sensing products. The objective is to study whether it is possible to explain
known problems in the SMOS soil moisture products and to identify potential approaches to
improve the data quality.
The land surface model PROMET (PRocesses Of Mass and Energy Transfer) and the
radiative transfer model L-MEB (L-band microwave emission of the Biosphere) are coupled
to simulate land surface states, e.g. temperatures and soil moisture, and the resulting
microwave emission. L-MEB is also used in the SMOS soil moisture processor to retrieve soil
moisture and vegetation optical depth simultaneously from the measured microwave
emission. The study area of this work is the Upper Danube Catchment, located mostly in
Southern Germany.
Since model validation is essential if model data are to be used as reference, both models are
validated on different spatial scales with measurements. The uncertainties of the models are
quantified. The root mean squared error between modelled and measured soil moisture at
several measuring stations on the point scale is 0.065 m3/m3. On the SMOS scale it is 0.039
m3/m3. The correlation coefficient on the point scale is 0.84.
As it is essential for the soil moisture retrieval from passive microwave data that the radiative
transfer modelling works under local conditions, the coupled models are used to assess the
radiative transfer modelling with L-MEB on the local and SMOS scales in the Upper Danube
Catchment. In doing so, the emission characteristics of rape are described for the first time
and the soil moisture retrieval abilities of L-MEB are assessed with a newly developed LMEB
parameterization. The results show that the radiative transfer modelling works well
under most conditions in the study area. The root mean squared error between modelled and
airborne measured brightness temperatures on the SMOS scale is less than 6 – 9 K for the
different look angles.
The coupled models are used to analyse SMOS brightness temperatures and vegetation optical
depth data in the Upper Danube Catchment in Southern Germany. Since the SMOS soil
moisture products are degraded in Southern Germany and in different other parts of the world
these analyses are used to narrow down possible reasons for this.
The thorough analysis of SMOS brightness temperatures for the year 2011 reveals that the
quality of the measurements is degraded like in the SMOS soil moisture product. This points
towards radio frequency interference problems (RFI), that are known, but have not yet been
studied thoroughly. This is consistent with the characteristics of the problems observed in the
SMOS soil moisture products. In addition to that it is observed that the brightness
temperatures in the lower look angles are less reliable. This finding could be used to improve
the brightness temperature filtering before the soil moisture retrieval.
An analysis of SMOS optical depth data in 2011 reveals that this parameter does not contain
valuable information about vegetation. Instead, an unexpected correlation with SMOS soil
moisture is found. This points towards problems with the SMOS soil moisture retrieval,
possibly under the influence of RFI.
The present thesis demonstrates that coupled land surface and radiative transfer models can
make a valuable contribution to the validation and analysis of passive microwave remote
sensing products. The unique approach of this work incorporates modelling with a high
spatial and temporal resolution on different scales. This makes detailed process studies on the
local scale as well as analyses of satellite data on the SMOS scale possible. This could be
exploited for the validation of future satellite missions, e.g. SMAP (Soil Moisture Active and
Passive) which is currently being prepared by NASA (National Aeronautics and Space
Administration). Since RFI seems to have a considerable influence on the SMOS data due to
the gained insights and the quality of the SMOS products is very good in other parts of the
world, the RFI containment and mitigation efforts carried out since the launch of SMOS
should be continued
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
From remote to urbanized: dispersal of antibiotic-resistant bacteria under the aspect of anthropogenic influence
No full textAntibiotic resistance is a growing global concern, but our understanding of the spread of resistant bacteria in remote regions remains limited. While some level of intrinsic resistance likely contributes to reduced susceptibility to antimicrobials in the environment, it is evident that human actions, particularly the (mis)use of antibiotics, play a significant role in shaping the environmental resistome, even in seemingly distant habitats like glacier ice sheets. Our research aims to bridge this knowledge gap by investigating the direct influence of human activities on the presence of antibiotic-resistant bacteria in various habitats. To achieve a comprehensive assessment of anthropogenic impact across diverse and seemingly isolated sampling sites, we developed an innovative approach utilizing Corine Land Cover data and heatmaps generated from sports activity trackers. This method allowed us to make meaningful comparisons across relatively pristine environments. Our findings indicate a noteworthy increase in culturable antibiotic-resistant bacteria with heightened human influence, as evidenced by our analysis of glacier, snow, and lake water samples. Notably, the most significant concentrations of antibiotic-resistant and multidrug-resistant microorganisms were discovered in two highly impacted sampling locations, namely the Tux Glacier and Gas Station Ellma
"Acquiferi virtuali" come strumento per la valutazione quantitativa dell'influenza dell'errore di campionamento sulla qualità della caratterizzazione di una falda inquinata
No full textPragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Dr. Edwin Wright Collection: Author Unknown
No full textNotes - The author relates several short stories about his neighbours including Alex McDonell, homesteading and life around Meanook and Athabasca (1 page
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
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