1,720,990 research outputs found
CLOUD ANALYSIS FROM GMS INFRARED IMAGERY DATA
No full textA new method is developed to estimate the total cloud amount from GMS imagery databy the Two-Threshold-Method (TTM) taking account of the spectral peaks due to the groundsurface and of the pixels totally covered by cloud. The approximate agreement is obtainedbetween the estimated values and the ground-observed cloud amounts over an area of about10 4 km2. The possibility of classification of cloud types from GMS IR data into low, middle, high and convective clouds is studied and found that they can be distinguished from each otherby TBB spectral parameters except the middle and convective clouds.A new method is developed to estimate the total cloud amount from GMS imagery databy the Two-Threshold-Method (TTM) taking account of the spectral peaks due to the groundsurface and of the pixels totally covered by cloud. The approximate agreement is obtainedbetween the estimated values and the ground-observed cloud amounts over an area of about10 4 km2. The possibility of classification of cloud types from GMS IR data into low, middle,high and convective clouds is studied and found that they can be distinguished from each otherby TBB spectral parameters except the middle and convective clouds
RAINFALL DISTRIBUTION OF BAIU FRONT SURROUNDING JAPANESE ISLANDS DURING JUNE 1989
No full textThe method developed for estimating rainfall over several sample areas over the main islands of Japan from IR imagery data of GMS is extended to estimate rainfall over a wider region including the Japanese islands and their adjacent ocean.In extended method, the proportional coefficients between rainfall and cold cloud fractional coverage, FC are assumed to be linear functions of latitudes and calculated for the 3 types of rainy clouds by using IR and rainfall data of AIP/1. The extended method gives a relatively good estimation of rainfall in applying to the whole AIP/1 data, with relative errors of 73% and 17% for daily and monthly estimation, respectively. Rainfall features of the Baiu season are then investigated through IR estimation for June 1989.The total monthly rainfall for the period is distributed in a band-like shape exteding from west to east, showing its maximum on 35ﾟN in the latitudinal section and a sudden decrease to the west of 130ﾟE in the longitudinal section. The latitudinal distributions of rainfall relative to the Baiu front show almost the same shape with their maximam at 1.25ﾟ north of the front at the surface over both land and ocean, but the peak amount is larger over the island than that over the ocean.The method developed for estimating rainfall over several sample areas over the main islands of Japan from IR imagery data of GMS is extended to estimate rainfall over a wider region including the Japanese islands and their adjacent ocean.In extended method, the proportional coefficients between rainfall and cold cloud fractional coverage, FC are assumed to be linear functions of latitudes and calculated for the 3 types of rainy clouds by using IR and rainfall data of AIP/1. The extended method gives a relatively good estimation of rainfall in applying to the whole AIP/1 data, with relative errors of 73% and 17% for daily and monthly estimation, respectively. Rainfall features of the Baiu season are then investigated through IR estimation for June 1989.The total monthly rainfall for the period is distributed in a band-like shape exteding from west to east, showing its maximum on 35ﾟN in the latitudinal section and a sudden decrease to the west of 130ﾟE in the longitudinal section. The latitudinal distributions of rainfall relative to the Baiu front show almost the same shape with their maximam at 1.25ﾟ north of the front at the surface over both land and ocean, but the peak amount is larger over the island than that over the ocean
RAINFALL ESTIMATION FROM GMS INFRARED IMAGERY DATA
No full textA new method is proposed for estimation of rainfall in mid-latitudinal area from GMS infrared imagery data. This method is developed by using the satellite and gage data in 5 areas of about 10^4 km^2 with similar meteorological conditions in Japan, taking account of the different features of rainfall from various types of clouds. In this method, cloud is classified by IR-parameters into six types, S(Clear Sky), F(Fine), A(cumulus), B(Cumulonimbus), C(Middle Clouds) and D(High Clouds), by using the discriminate analysis technique. The cloud types, S, F and D are assumed to be no-rain cases. In the case of A, B and C, the rainfall is assumed to be proportional to the cold cloud fractional coverage (FC), for which the proportional constant is determined by the regressional equation between FC and 3-hr rainfall, where the threshold value to define FC are determined to give the highest correlation between them. This method gives a good rainfall estimation for 24-hr rainfall with the correlation coefficient of 0.65 and relative root mean square error of 0.94. An application of this method to Hokkaido area also gives a good estimation of 24-hr rainfall if an adjustment factor is introduced, suggesting a possible application of this mothod to areas with different meteorological conditions.A new method is proposed for estimation of rainfall in mid-latitudinal area from GMS infrared imagery data. This method is developed by using the satellite and gage data in 5 areas of about 10^4 km^2 with similar meteorological conditions in Japan, taking account of the different features of rainfall from various types of clouds. In this method, cloud is classified by IR-parameters into six types, S(Clear Sky), F(Fine), A(cumulus), B(Cumulonimbus), C(Middle Clouds) and D(High Clouds), by using the discriminate analysis technique. The cloud types, S, F and D are assumed to be no-rain cases. In the case of A, B and C, the rainfall is assumed to be proportional to the cold cloud fractional coverage (FC), for which the proportional constant is determined by the regressional equation between FC and 3-hr rainfall, where the threshold value to define FC are determined to give the highest correlation between them. This method gives a good rainfall estimation for 24-hr rainfall with the correlation coefficient of 0.65 and relative root mean square error of 0.94. An application of this method to Hokkaido area also gives a good estimation of 24-hr rainfall if an adjustment factor is introduced, suggesting a possible application of this mothod to areas with different meteorological conditions
NIGHT OBSERVATION OF CLOUD AMOUNT AND TYPE FROM GMS INFRARED IMAGE
No full textMethods for estimating cloud amount and type from GMS IR imaegry data developed forthe daytime are applied to nighttime data. Cloud amount is estimated by a Two ThresholdMethod (TTM) which takes account of the ground related spectral peak and of the partiallycloud-covered pixels. Cloud type is classified by a discriminant analysis technique. The resultsshow a correlation coefficient of 0.659 and correctness ratio of 47.7% with comparison to theground observations. These values are a little worse than those in daytime (0.869 and 52.9%respectively), but suggesting the possibility to applying to all data. The methods are applied toproduce the time series of cloud amounts and types for the period from 3 to 11 Sept. 1980. Thevariation trend of satellite derived cloud appeared to reflect the change of weather systems andto agree with the surface cloud observation comparatively well.Methods for estimating cloud amount and type from GMS IR imaegry data developed forthe daytime are applied to nighttime data. Cloud amount is estimated by a Two ThresholdMethod (TTM) which takes account of the ground related spectral peak and of the partiallycloud-covered pixels. Cloud type is classified by a discriminant analysis technique. The resultsshow a correlation coefficient of 0.659 and correctness ratio of 47.7% with comparison to theground observations. These values are a little worse than those in daytime (0.869 and 52.9%respectively), but suggesting the possibility to applying to all data. The methods are applied toproduce the time series of cloud amounts and types for the period from 3 to 11 Sept. 1980. Thevariation trend of satellite derived cloud appeared to reflect the change of weather systems andto agree with the surface cloud observation comparatively well
RAINFALL ESTIMATION FROM GMS INFRARED AND VISIBLE IMAGERY DATA
No full textRainfall estimation in midlatitude by the use of geostationary meteorological satellite (GMS)infrared and visible imagery data was studied. A preliminary study of the relationship betweenground observed cloudiness and rainfall reveals that the upper layer cloud like cirrus causes norain and that rainfall by convective cloud is roughly proportional to the cloud amount. The rela-tion between types of clouds and IR-VIS 2-dimensional frequency distributions shows that upperlayer cloud can be identified by the peak with an albedo less than 0.4, and that the groundobserved cloud amount is well proportional to the fractional coverage of the satellite data. Basedupon these results, a twe-step rain estimation method is developed; determination of rain/no-rainby peak position, followed by calculation of the rainfall with regression equation using the frac-tional coverage.Rainfall estimation in midlatitude by the use of geostationary meteorological satellite (GMS)infrared and visible imagery data was studied. A preliminary study of the relationship betweenground observed cloudiness and rainfall reveals that the upper layer cloud like cirrus causes norain and that rainfall by convective cloud is roughly proportional to the cloud amount. The rela-tion between types of clouds and IR-VIS 2-dimensional frequency distributions shows that upperlayer cloud can be identified by the peak with an albedo less than 0.4, and that the groundobserved cloud amount is well proportional to the fractional coverage of the satellite data. Basedupon these results, a twe-step rain estimation method is developed; determination of rain/no-rainby peak position, followed by calculation of the rainfall with regression equation using the frac-tional coverage
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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