1,720,979 research outputs found
Potential Sites for Future Lake Formation in Glaciers of Chandra Basin, Western Himalayas, India
No full textThe disappearance of mountain glaciers and the formation or expansion of glacial lakes are amongst the most distinguishable and dynamic impacts of climate warming in the Himalayas. The given dataset provides the potential sites for future lake formation over 65 study glaciers in the Chandra basin of the western Himalayas
Modified-INSAT Multi-Spectral Rainfall Algorithm (M-IMSRA) at climate region scale: Development and validation
No full textThe present article reports an improvement in the INSAT Multispectral Rainfall Algorithm which is currently operational in the Indian Meteorological Department (IMD). The proposed Modified-IMSRA (M-IMSRA) algorithm deviates from original IMSRA in two ways: first is by improvement in rain/no-rain area detection scheme using a Multi Index Rain Detection (MIRD) index; second is based on the climate region-wise correction through Least Absolute Shrinkage and Selection Operator (LASSO) models developed for each climate regions using rainfall (obtained based on first improvement) and static topographic variables extracted from Digital Elevation Model (DEM). The overall results indicate that the M-IMSRA is performing better than the IMSRA in all climatic regions when compared with the IMD gridded gauge data. However, the improvement is not uniform in all the regions. The inclusion of the MIRD index led to considerable improvement in M-IMSRA-based rainfall estimates mainly in the arid regions. Likewise, the results obtained after the LASSO regression corrections indicate that they are necessary only for the orographic regions where significant improvements are observed in the rainfall estimates. Finally, the inter-comparison of the simple hybrid M-IMSRA estimates with Tropical Rainfall Measuring Mission (TRMM) 3B42 V7 and TRMM 3B42-RT V7 illustrates that the M-IMSRA performs nearly as well as even better (except in terms of Correlation Coefficient) than the complex multi-satellite-based rainfall estimates in all the climate regions of India. Considering the above results, it can be said that the performance of simple hybrid algorithms such as IMSRA can be improved to match the quality or even outperform complex multi-satellite rainfall estimates by incorporating appropriate corrections. (C) 2016 Elsevier Inc. All rights reserved
Error modelling for modified-INSAT multi-spectral rainfall algorithm
No full textConsidering the importance of the error estimates for satellite rainfall products in various applications, the present article deals with the development of an Error Model for Modified-INSAT Multi-Spectral Rainfall Algorithm (M-IMSRA) Estimates (EMME), a recently developed climate region scale rainfall algorithm across India. A non-parametric framework has been adopted to model all the four error components: Correct No-Rain Detection, Miss Rain, False Rain, and Hit Rain in M-IMSRA estimates at climate region scale. The developed error model generated convincing realization of reference rainfall for the estimated rainfall from M-IMSRA algorithm across all the climate regions of India. Exceptions are the high intensity hit rain events across arid Thar Desert and arid Himalayan regions and miss rain events across arid Himalayan region. Overall, the developed error model showed promising results in modelling hit, miss, and false error components of daily M-IMSRA estimates and thus can be associated with the M-IMSRA estimates
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
Generation and Validation of the Interferometric SAR DEMs from TanDEM-X data for Gangotri and Hamtah Glaciers of Indian Himalayas
No full textAbstractTanDEM-X SAR mission was launched in June, 2010 with an aim to generate high resolution global DEMs of HRTI-3 specification. Considering this, it is very important to evaluate the accuracy of the DEM generated using TanDEM-X InSAR data over the rugged terrains of Indian Himalayas. This paper presents the results of an evaluation study of the DEMs generated through interferometric technique using TanDEM-X data over two Indian Himalayan glaciers viz. Hamtah and Gangotri. The two generated DEMs have been compared with the corresponding accurate Differential Global Positioning System (DGPS) values. On the basis of comparison of the elevation values between TanDEM-X DEM and DGPS data, it is observed that the Hamtah and Gangotri glacier DEMs show RMSE values 7.0 m and 8.2 m respectively. To evaluate the performance between TanDEM-X DEM and SRTM DEM, the SRTM DEM of the Hamtah glacier has also been compared with the DPGS points of Hamtah glacier and found to have a RMSE of 13.5m. Overall, the obtained results indicate that the generated TanDEM-X DEMs are of superior quality
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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Dual correction of rainfall and root zone soil moisture estimates for improving streamflow simulations
Full text linkSatellite-based precipitation and soil moisture products are often associated with significant uncertainties, rendering them less reliable for hydrological applications. The present study proposes a dual correction scheme employing satellite-based soil moisture estimates to update satellite-based rainfall and modelled soil moisture states. First, the artificial neural network (ANN) was utilised to correct TRMM 3B42RT rain rate estimates using ASCAT soil moisture observations. Subsequently, the ASCAT surface soil moisture observations were scaled to root-zone level using the Soil Moisture Analytical Relationship and assimilated into the Soil and Water Assessment Tool model through the ensemble Kalman filter (EnKF) technique. The correction to the 3B42RT rainfall was evaluated using observed rainfall data, whereas the modelled streamflow was assessed under three correction schemes: sole rainfall correction (forcing correction), sole soil moisture assimilation (state correction), and combined forcing and state correction (dual correction). The results demonstrated that the artificial neural network-based rainfall correction technique improved the 3B42RT rainfall, with an average reduction in RMSE of 7.5 mm and a 10% improvement in NSE. The streamflow evaluation revealed that the forcing correction primarily enhanced the quick-flow component of simulated streamflow, with an assimilation efficiency of 17.3%, whereas the state correction scheme improved the base-flow component (assimilation efficiency of 21.9%). The dual correction combined the benefits of both schemes to achieve an assimilation efficiency of 28.9%. The forecasting performance indicated that the dual correction strategy provided maximum improvement of up to two lead days in the selected catchment. Overall, the dual correction strategy based on ANN and the EnKF promotes the use of satellite-based rainfall and soil moisture data for hydrological applications
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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