The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Kimiaki Saito - One of the best experts on this subject based on the ideXlab platform.
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Spatial properties of soil analyses and Airborne measurements for reconnaissance of soil contamination by 137 Cs after Fukushima nuclear accident in 2011
Journal of Environmental Radioactivity, 2019Co-Authors: Pedram Masoudi, Mathieu Le Coz, Charlotte Cazala, Kimiaki SaitoAbstract:HIGHLIGHTS-Soil analyses and Airborne measurements are compared to each other.-In 47% of cases, both the datasets are compatible in small-and large-dimension variations.-Despite the general consistency of data, soil analyses are more heterogeneous.-Spatial-correlation within the variable could be a witness of hotspots in low-contaminated zones. ABSTRACT Following Fukushima nuclear disaster, several data gathering campaigns Surveyed the radionuclide propagation in the environment. However, the acquired datasets do not have the same sampling dimension. For example, the Airborne measurements are some sort of averaging over a circular field of view, beneath the sensor; while the soil analyses are much more punctual. The objective of this work is to compare the soil samples and an Airborne Survey to investigate whether these two datasets reflect the same spatial patterns or not. This is prerequisite for combining the multiresolution data to create and update the contamination map in a post-accidental situation. The analyses were performed on square tiles of 20 km side to study large-and small-dimension variations in 137 Cs concentration. The former was modelled by fitting a plane (called trend) to the georeferenced data points; and the latter was modelled by computing the difference (called residual) between the trend and the initial data. Dip direction and dip angle of trends as well as minimum spatial correlation distance and anisotropy of residuals were computed for both the soil and Airborne datasets and compared. Dip directions are compatible in 73% of the tiles and dip angles are generally close. Anisotropy directions are compatible in 49% of the tiles and minimum spatial correlation distances are significantly more marked for the Airborne dataset. The soil samples and Airborne measurements are therefore more in agreement in large-dimension (trend) rather than in small-dimension (residual) variations. More generally, both the datasets allow highlighting the main contamination plumes distinguishable because of high concentration values. The Airborne dataset yet appears to be more powerful to quantify spatial correlations, which could be linked to the contamination mechanisms.
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Spatial properties of soil analyses and Airborne measurements for reconnaissance of soil contamination by 137Cs after Fukushima nuclear accident in 2011
Journal of Environmental Radioactivity, 2019Co-Authors: Pedram Masoudi, Mathieu Le Coz, Charlotte Cazala, Kimiaki SaitoAbstract:Following Fukushima nuclear disaster, several data gathering campaigns Surveyed the radionuclide propagation in the environment. However, the acquired datasets do not have the same sampling dimension. For example, the Airborne measurements are some sort of averaging over a circular field of view, beneath the sensor; while the soil analyses are much more punctual. The objective of this work is to compare the soil samples and an Airborne Survey to investigate whether these two datasets reflect the same spatial patterns or not. This is prerequisite for combining the multiresolution data to create and update the contamination map in a post-accidental situation. The analyses were performed on square tiles of 20 km side to study large- and small-dimension variations in 137Cs concentration. The former was modelled by fitting a plane (called trend) to the georeferenced data points; and the latter was modelled by computing the difference (called residual) between the trend and the initial data. Dip direction and dip angle of trends as well as minimum spatial correlation distance and anisotropy of residuals were computed for both the soil and Airborne datasets and compared. Dip directions are compatible in 73% of the tiles and dip angles are generally close. Anisotropy directions are compatible in 49% of the tiles and minimum spatial correlation distances are significantly more marked for the Airborne dataset. The soil samples and Airborne measurements are therefore more in agreement in large-dimension (trend) rather than in small-dimension (residual) variations. More generally, both the datasets allow highlighting the main contamination plumes distinguishable because of high concentration values. The Airborne dataset yet appears to be more powerful to quantify spatial correlations, which could be linked to the contamination mechanisms.
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A Multiscale Bayesian Data Integration Approach for Mapping Radionuclide Contamination
Resilience: A New Paradigm of Nuclear Safety, 2017Co-Authors: Haruko M. Wainwright, Masahiko Okumura, Kimiaki SaitoAbstract:This chapter presents a multiscale data fusion method to estimate the spatial distribution of radiation dose rates at regional scale around the Fukushima Daiichi nuclear power plant. We integrate various types of radiation measurements, such as ground-based hand-held monitors, car-borne Surveys, and Airborne Surveys, all of which have different resolutions, spatial coverage, and accuracy. This method is based on geostatistics to represent spatial heterogeneous structures, and also on Bayesian hierarchical models to integrate multiscale, multitype datasets in a consistent manner. Although this approach is primarily data-driven, it has great flexibility, enabling it to include mechanistic models for representing radiation transport or other complex processes and correlations. As a first demonstration, we show a simple case study in which we integrate two datasets over Fukushima City, Japan: (1) coarse-resolution Airborne Survey data covering the entire city and (2) high-resolution ground-based car-borne data along major roads. Results show that the method can successfully integrate two datasets in a consistent manner and generate an integrated map of air dose rates over the domain in high resolution. A further advantage of this method is that it can quantify estimation errors and estimate confidence intervals, which are necessary for modeling and for robust policy planning. In addition, evaluating correlations among different datasets provides us with various insights into the characteristics of each dataset, as well as radionuclide transport and distribution. The resulted maps have started being used by local governments to plan the residents’ return, and they are expected to be used for additional policy decisions in the future such as decontamination planning.
Yoh Tanimoto - One of the best experts on this subject based on the ideXlab platform.
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Further comments on "Individual external dose monitoring of all citizens of Date City by passive dosimeter 5 to 51 months after the Fukushima NPP accident (series): 1." : Inconsistencies in Table 1 2014 Q3 and Figure 4f
arXiv: Medical Physics, 2020Co-Authors: Shin-ichi Kurokawa, Yutaka Hamaoka, Kyo Kageura, Jun Makino, Masaki Oshikawa, Yoh TanimotoAbstract:We point out serious inconsistencies of the first paper of the series, written by Makoto Miyazaki and Ryugo Hayano, which discusses the correlation between the personal doses of the citizens of Date City measured by glass badges with the ambient dose rates measured by six Airborne Surveys. The last of the six Airborne Survey was made in the period of 2014 Q3 (from October 2014 to December 2014). The real number of participants of the period is about 14,500; however, in Table 1 2014 Q3 it is written that the number of participants is 21,080 and in Fig. 4f 21,052. We conclude that the analysis of the paper with respect to Table 1 2014 Q3 and Fig. 4f are done without using real correct data and we cannot obtain any meaningful information from the table and figure. Since the period 2014 Q3 is also included in Fig. 5 of the second paper of the series, it is quite possible that Fig. 5 of the second paper is made on the basis of, at least partially, false data and is not reliable.
Pedram Masoudi - One of the best experts on this subject based on the ideXlab platform.
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Spatial properties of soil analyses and Airborne measurements for reconnaissance of soil contamination by 137Cs after Fukushima nuclear accident in 2011
Journal of Environmental Radioactivity, 2019Co-Authors: Pedram Masoudi, Mathieu Le Coz, Charlotte Cazala, Kimiaki SaitoAbstract:Following Fukushima nuclear disaster, several data gathering campaigns Surveyed the radionuclide propagation in the environment. However, the acquired datasets do not have the same sampling dimension. For example, the Airborne measurements are some sort of averaging over a circular field of view, beneath the sensor; while the soil analyses are much more punctual. The objective of this work is to compare the soil samples and an Airborne Survey to investigate whether these two datasets reflect the same spatial patterns or not. This is prerequisite for combining the multiresolution data to create and update the contamination map in a post-accidental situation. The analyses were performed on square tiles of 20 km side to study large- and small-dimension variations in 137Cs concentration. The former was modelled by fitting a plane (called trend) to the georeferenced data points; and the latter was modelled by computing the difference (called residual) between the trend and the initial data. Dip direction and dip angle of trends as well as minimum spatial correlation distance and anisotropy of residuals were computed for both the soil and Airborne datasets and compared. Dip directions are compatible in 73% of the tiles and dip angles are generally close. Anisotropy directions are compatible in 49% of the tiles and minimum spatial correlation distances are significantly more marked for the Airborne dataset. The soil samples and Airborne measurements are therefore more in agreement in large-dimension (trend) rather than in small-dimension (residual) variations. More generally, both the datasets allow highlighting the main contamination plumes distinguishable because of high concentration values. The Airborne dataset yet appears to be more powerful to quantify spatial correlations, which could be linked to the contamination mechanisms.
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Spatial properties of soil analyses and Airborne measurements for reconnaissance of soil contamination by 137 Cs after Fukushima nuclear accident in 2011
Journal of Environmental Radioactivity, 2019Co-Authors: Pedram Masoudi, Mathieu Le Coz, Charlotte Cazala, Kimiaki SaitoAbstract:HIGHLIGHTS-Soil analyses and Airborne measurements are compared to each other.-In 47% of cases, both the datasets are compatible in small-and large-dimension variations.-Despite the general consistency of data, soil analyses are more heterogeneous.-Spatial-correlation within the variable could be a witness of hotspots in low-contaminated zones. ABSTRACT Following Fukushima nuclear disaster, several data gathering campaigns Surveyed the radionuclide propagation in the environment. However, the acquired datasets do not have the same sampling dimension. For example, the Airborne measurements are some sort of averaging over a circular field of view, beneath the sensor; while the soil analyses are much more punctual. The objective of this work is to compare the soil samples and an Airborne Survey to investigate whether these two datasets reflect the same spatial patterns or not. This is prerequisite for combining the multiresolution data to create and update the contamination map in a post-accidental situation. The analyses were performed on square tiles of 20 km side to study large-and small-dimension variations in 137 Cs concentration. The former was modelled by fitting a plane (called trend) to the georeferenced data points; and the latter was modelled by computing the difference (called residual) between the trend and the initial data. Dip direction and dip angle of trends as well as minimum spatial correlation distance and anisotropy of residuals were computed for both the soil and Airborne datasets and compared. Dip directions are compatible in 73% of the tiles and dip angles are generally close. Anisotropy directions are compatible in 49% of the tiles and minimum spatial correlation distances are significantly more marked for the Airborne dataset. The soil samples and Airborne measurements are therefore more in agreement in large-dimension (trend) rather than in small-dimension (residual) variations. More generally, both the datasets allow highlighting the main contamination plumes distinguishable because of high concentration values. The Airborne dataset yet appears to be more powerful to quantify spatial correlations, which could be linked to the contamination mechanisms.
Shin-ichi Kurokawa - One of the best experts on this subject based on the ideXlab platform.
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Further comments on "Individual external dose monitoring of all citizens of Date City by passive dosimeter 5 to 51 months after the Fukushima NPP accident (series): 1." : Inconsistencies in Table 1 2014 Q3 and Figure 4f
arXiv: Medical Physics, 2020Co-Authors: Shin-ichi Kurokawa, Yutaka Hamaoka, Kyo Kageura, Jun Makino, Masaki Oshikawa, Yoh TanimotoAbstract:We point out serious inconsistencies of the first paper of the series, written by Makoto Miyazaki and Ryugo Hayano, which discusses the correlation between the personal doses of the citizens of Date City measured by glass badges with the ambient dose rates measured by six Airborne Surveys. The last of the six Airborne Survey was made in the period of 2014 Q3 (from October 2014 to December 2014). The real number of participants of the period is about 14,500; however, in Table 1 2014 Q3 it is written that the number of participants is 21,080 and in Fig. 4f 21,052. We conclude that the analysis of the paper with respect to Table 1 2014 Q3 and Fig. 4f are done without using real correct data and we cannot obtain any meaningful information from the table and figure. Since the period 2014 Q3 is also included in Fig. 5 of the second paper of the series, it is quite possible that Fig. 5 of the second paper is made on the basis of, at least partially, false data and is not reliable.
Jorg M. Hacker - One of the best experts on this subject based on the ideXlab platform.
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Ultrafine particles over Eastern Australia: an Airborne Survey
Tellus B: Chemical and Physical Meteorology, 2015Co-Authors: Wolfgang Junkermann, Jorg M. HackerAbstract:Ultrafine particles (UFP) in the atmosphere may have significant impacts on the regional water and radiation budgets through secondary effects on cloud microphysics. Yet, as these particles are invisible for current remote sensing techniques, knowledge about their three-dimensional distribution, source strengths and budgets is limited. Building on a 40-yr-old Australia-wide Airborne Survey which provides a reference case study of aerosol sources and budgets, this study presents results from a new Airborne Survey over Eastern Australia, northern New South Wales and Queensland. Observations identified apparent changes in the number and distribution of major anthropogenic aerosol sources since the early 1970s, which might relate to the simultaneously observed changes in rainfall patterns over eastern Queensland. Coal-fired power stations in the inland areas between Brisbane and Rockhampton were clearly identified as the major sources for ultrafine particulate matter. Sugar mills, smelters and shipping along the coast close to the Ports of Townsville and Rockhampton were comparable minor sources. Airborne Lagrangian plume studies were applied to investigate source strength and ageing properties within power station plumes. Significant changes observed, compared to the measurements in the 1970s, included a significant increase in the number concentration of UFP related to coal-fired power station emissions in the sparsely populated Queensland hinterland coincident with the area with the most pronounced reduction in rainfall
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ultrafine particles over eastern australia an Airborne Survey
Tellus B, 2015Co-Authors: Wolfgang Junkermann, Jorg M. HackerAbstract:Ultrafine particles (UFP) in the atmosphere may have significant impacts on the regional water and radiation budgets through secondary effects on cloud microphysics. Yet, as these particles are invisible for current remote sensing techniques, knowledge about their three-dimensional distribution, source strengths and budgets is limited. Building on a 40-yr-old Australia-wide Airborne Survey which provides a reference case study of aerosol sources and budgets, this study presents results from a new Airborne Survey over Eastern Australia, northern New South Wales and Queensland. Observations identified apparent changes in the number and distribution of major anthropogenic aerosol sources since the early 1970s, which might relate to the simultaneously observed changes in rainfall patterns over eastern Queensland. Coal-fired power stations in the inland areas between Brisbane and Rockhampton were clearly identified as the major sources for ultrafine particulate matter. Sugar mills, smelters and shipping along the coast close to the Ports of Townsville and Rockhampton were comparable minor sources. Airborne Lagrangian plume studies were applied to investigate source strength and ageing properties within power station plumes. Significant changes observed, compared to the measurements in the 1970s, included a significant increase in the number concentration of UFP related to coal-fired power station emissions in the sparsely populated Queensland hinterland coincident with the area with the most pronounced reduction in rainfall. Keywords: power station, emission, coal, aerosol, precipitation, regional climate impact (Published: 27 April 2015) Citation: Tellus B 2015, 67, 25308, http://dx.doi.org/10.3402/tellusb.v67.25308
