1,720,958 research outputs found
Transferring remotely sensed predictions of drought events on Bornean rainforests
No full textIn order to inform the development of a remote sensing drought monitoring system
over Sabah, Borneo, this paper explored how a relationship between remotely
sensed data and rainfall developed at one site in Sabah transferred to four other sites in Sabah. By way of developing relationships between rainfall statistics collected at
five Sabah rainforest sites and remotely sensed data (acquired by NOAA AVHRR)
processed to MIR reflectance, the VI3 index, the Ts/NDVI index and Ts/VI3 index,
two points were concluded. The first was that the relationship between remotely
sensed data and rainfall is non-stationary across Sabah during the 1997/1998 ENSO
and the second was that the index Ts/VI3 is an effective means of using the remotely
sensed data available
Dynamics of ENSO drought events on Sabah rainforests observed by NOAA AVHRR
No full textDrought, associated with the El Nin˜o Southern Oscillation (ENSO), can have
considerable impact on tropical rainforests. Concern over drought, particularly
given the possibility of an increase in its occurrence and intensity, has fostered a
desire for an increased understanding of drought events and their impact to
inform the development of a drought monitoring system. This paper investigates
the use of National Oceanic and Atmospheric Administration (NOAA)
Advanced Very High Resolution Radiometer (AVHRR) data in a drought
monitoring system for the rainforests of Sabah, Borneo. These rainforests are
dynamic with respect to their coupling with ENSO processes and in their
biophysical properties, and such dynamism may have implications for how
NOAA AVHRR data may be used. In particular, this paper explores the
transferability of relationships between a drought indicator (rainfall) and the
response of the rainforest, as measured by four NOAA AVHRR variables
(middle infrared reflectance; VI3; Ts/VI3 and Ts/NDVI), under particular site
conditions. It was found that both spatial variability in forest biophysical
properties and geographical variability in drought impact had implications for
the transferability of relationships developed under local conditions across Sabah
rainforests within a drought monitoring system. Suggestions are presented for
how NOAA AVHRR data could be used, with a new drought monitoring index –
the Ts/VI3 – recommended
Spatio-temporal response of extreme events on Bornean rainforests
No full textThe relationship between middle infrared reflectance and various scenarios of preceeding rainfall for a range of tropical forest types is investigated. Statistically significant correlations for the relationship were generally observed when the rainfall data were acquired over a period of about a month with a short time lag before image acquisition
Remote monitoring of impacts of ENSO related drought areas on Sabah rainforests
No full textThe performance of the NOAA AVHRR derived V13 vegetation index, relative to the NDVI, for monitoring impacts of the 1997-1998 ENSO related drought stress on Sabah rainforests was explored. Results demonstrated that the V13 index, which incorporates MIR reflectance, was more strongly correlated to rainfall values of this ENSO event than the more widely used NDVI. Moreover, maximum correlation was achieved at a longer lag period using the V13 than the NDVI, demonstrating its possible utility in a forecasting and monitoring system of ENSO related drought impacts on Sabah rainforest
Exploring the utility of NOAA AVHRR middle infrared reflectance to monitor the impacts of ENSO-induced drought stress on Sabah rainforests
No full textThe ever-wet tropics are under threat from ENSO events and there is a need for a monitoring system to analyse and describe their responses to such events. This letter explores the relative value of using NOAA AVHRR middle infrared (MIR) reflectance data and NDVI data for the monitoring of ENSO-related drought stress of a tropical forest ecosystem in Sabah, Malaysia. Relationships between rainfall and MIR reflectance were examined. Correlation coefficients are generally large and significant (at 0.1 level) while those between rainfall and NDVI were small and insignificant. This letter concludes that there is potential in using MIR reflectance for monitoring the effects of ENSO-induced drought stress on these forests and this has a bearing on how NOAA AVHRR data may be used to further our knowledge on the impacts of ENSO events on tropical forest environments
Remote monitoring of the impact of ENSO-related drought on Sabah rainforests using NOAA AVHRR middle infrared reflectance: exploring emissivity uncertainty
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
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