The Experts below are selected from a list of 51 Experts worldwide ranked by ideXlab platform
Katalin Gillemot - One of the best experts on this subject based on the ideXlab platform.
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Measurement inter-comparison of bulk snow density and water equivalent of snow cover with snow Core Samplers
2020Co-Authors: Leena Leppänen, Juan Ignazio Lopez-moreno, Bartłomiej Luks, Ladislav Holko, Ghislain Picard, Alba Sanmiguel-vallelado, Esteban Alonso-gonzález, David Finger, Ali Nadir Arslan, Katalin GillemotAbstract:<p>Manually collected snow data can be considered as ground truth for many applications, such as climatological or hydrological studies. Water equivalent of snow cover (SWE) can be manually measured by using a snow tube or snow cylinder to extract a snow Core and measure the bulk density of the Core by weighing it. Different snow Core Samplers and scales are used, but they all use the same measurement principle. However, there are various sources of uncertainty that have not been quantified in detail. To increase the understanding of these errors, different manual SWE measurement devices used across Europe were evaluated within the framework of the COST Action ES1404 HarmoSnow. Two field campaigns were organized in different environments to quantify uncertainties when measuring snow depth, snow bulk density and SWE with Core Samplers. The 1<sup>st</sup> field campaign in 2017 in Iceland focused on measurement differences attributed to different instrumentation compared with the natural variability in the snowpack, and the 2<sup>nd</sup> field campaign in 2018 in Finland focused on device comparison and on the separation of the different sources of variability. To our knowledge, such a comparison has not previously been conducted in terms of the number of device and different environments.</p><p>During the 1<sup>st</sup> campaign, repeated measurements were taken along two 20 m long snow trenches to distinguish snow variability measured at the plot and at the point scale. The results revealed a much higher variability of SWE at the plot scale, resulting from both natural variability and instrument bias, compared to repeated measurements at the same spot, resulting mostly from error induced by observers or a high variability in the snow depth. Snow Micro Pen sampling showed that the snowpack was very homogeneous for the 2<sup>nd</sup> campaign, which allowed for the disregarding of the natural variability of the snowpack properties and the focus to be on separating between instrumental bias and error induced by observers. Results confirmed that instrumental bias exceeded both the natural variability and the error induced by observers, even when observers performed measurements with snow Core Samplers they were not formally trained on. Under such measurement conditions, the uncertainty in bulk snow density estimation is about 5% for an individual instrument and is close to 10% among different instruments. The results showed that the devices provided slightly different uncertainties since they were designed for different snow conditions. The aim of this comparison was not to provide a definitive estimation of uncertainty for manual SWE measurements, but to illustrate the role of the different uncertainty sources.</p>
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intercomparison of measurements of bulk snow density and water equivalent of snow cover with snow Core Samplers instrumental bias and variability induced by observers
Authorea Preprints, 2019Co-Authors: Ignacio Lopezmoreno, Leena Leppänen, Bartłomiej Luks, Ladislav Holko, Ghislain Picard, David Finger, Ali Nadir Arslan, Alba Sanmiguelvallelado, Esteban Alonsogonzalez, Katalin GillemotAbstract:Manually collected snow data are often considered as ground truth for many applications such as climatological or hydrological studies. However, there are many sources of uncertainty that are not quantified in detail. For the determination of water equivalent of snow cover (SWE), different snow Core Samplers and scales are used, but they are all based on the same measurement principle. We conducted two field campaigns with 9 Samplers commonly used in observational measurements and research in Europe and northern America to better quantify uncertainties when measuring depth, density and SWE with Core Samplers. During the first campaign, as a first approach to distinguish snow variability measured at the plot and at the point scale, repeated measurements were taken along two 20 m long snow pits. The results revealed a much higher variability of SWE at the plot scale (resulting from both natural variability and instrumental bias) compared to repeated measurements at the same spot (resulting mostly from error induced by observers or very small scale variability of snow depth). The exceptionally homogeneous snowpack found in the second campaign permitted to almost neglect the natural variability of the snowpack properties and focus on the separation between instrumental bias and error induced by observers. Under such measurement conditions, the uncertainty in bulk snow density estimation is about 5% for an individual instrument and is close to 10% among different instruments. Results confirmed that instrumental bias exceeded both the natural variability and the error induced by observers, even in the case when observers were not familiar with a given snow Core sampler.
R. J. Morrison - One of the best experts on this subject based on the ideXlab platform.
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Trace metals in sediments of four harbours in Guam
Marine Pollution Bulletin, 2005Co-Authors: G. R.w. Denton, Lucrina P. Concepcion, H.r. Wood, R. J. MorrisonAbstract:Harbours, because of the associated shipping activi-ties, are often sites of serious marine pollution. As a re-sult of the work of international (e.g., the International Maritime Organization and the United Nations Envi-ronment Program) and national agencies, there have been significant improvements recently in the operations and environments of many harbours, but historical activities have often left a pollution impact in the sedi-ments. Guam (13°28 0 N, 144°45 0 E) has been the major shipping centre in Micronesia for about 400 years, but there have been few studies of the impacts on the coastal environment of such activities. This paper reports the first major study of trace metals in sediments of four harbours in Guam. Users of GuamÕs harbours have included the military (since World War II), commercial shippers, commercial and recreational fishermen, tourist operators (dinner cruises, diving, jet-skiing, sailing, etc.), and the general public. All associated activities have the potential to im-pact on the local marine environment and only in the last 20–30 years have any controls on pollution been introduced. As a result, some contamination of sedi-ments is to be expected, but the extent was unknown be-fore this study. The four harbours (Fig. 1a) were selected on the following basis: Agana Boat Basin (major small boat harbour—5 sites); Outer Apra Harbour (heavily used commercial and military port—30 sites); Agat Marina (newly constructed small boat harbour—4 sites); and Merizo Pier (small boat harbour away from indus-trial activity—5 sites). Sediment samples were collected by scuba divers between May 16 and June 12, 1997. Site selection (Fig. 1b–e) was based primarily on proximity to poten-tial sources of contamination (e.g., storm water outlets, mooring sites, wharves, piers, fueling stations, electrical substations, etc.) along presumed concentration gradi-ents. Site locations were pinpointed using digital ortho-photo imagery maps with reference to prominent landmarks. Samples were collected at depths ranging from 0.5 to 17 m, using stainless steel Core Samplers (5 · 30 cm) fitted with pre-cleaned aluminium liners and Teflon lined plastic end-caps. A slide hammer was used to push each Corer 15–30 cm into the sediment depending on the nature of the underlying substrate. Three Cores were sampled within a 3 m diameter circle at each site, and each Core was analysed separately. Because of difficulties encountered in extracting the charged liners from the body of the Corers, the collected sediments were expelled into clean aluminium liners by inversion, wrapped in aluminium foil and stored on ice. In the laboratory, the entire contents of each liner were dislodged into a glass bowl and thoroughly mixed with a polyethylene spatula following the removal of large rocks, shells and other such bulky materials. Sub-samples for petrographic and particle size analysis were dried at room temperature, and sub-samples for metal analyses were placed in acid cleaned polyethylene vials and dried to constant weight at 60 °C. Residual sediment samples were stored in pre-cleaned glass jars at À20 °C for further analysis if necessary. Petrographic assessment (colour, sorting, dominant constituent identification and particle size) was made on the dried sediments. Sieve shaker analysis produced data on 4 size fractions: >2 mm (gravel); 1–2 mm (very coarse sand); 1 mm–63 lm (coarse to very fine sand);
Joseph F Rovani - One of the best experts on this subject based on the ideXlab platform.
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new soil voc Samplers en Core and accu Core sampling storage devices for voc analysis
2006Co-Authors: Susan S Sorini, John F Schabron, Joseph F RovaniAbstract:Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An ASTM International (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis and specifies sample storage in the En Core sampler at 4 {+-} 2 C for up to 48 hours; -7 to -21 C for up to 14 days; or 4 {+-} 2 C for up to 48 hours followed by storage at -7 to -21 C for up to five days. This report discusses activities performed during the past year to promote and continue acceptance of the En Core Samplers based on their performance to store soil samples for VOC analysis. The En Core sampler is designed to collect soil samples for VOC analysis at the soil surface. To date, a samplingmore » tool for collecting and storing subsurface soil samples for VOC analysis is not available. Development of a subsurface VOC sampling/storage device was initiated in 1999. This device, which is called the Accu Core{trademark} sampler, is designed so that a soil sample can be collected below the surface using a dual-tube penetrometer and transported to the laboratory for analysis in the same container. Laboratory testing of the current Accu Core design shows that the device holds low-level concentrations of VOCs in soil samples during 48-hour storage at 4 {+-} 2 C and that the device is ready for field evaluation to generate additional performance data. This report discusses a field validation exercise that was attempted in Pennsylvania in 2004 and activities being performed to plan and conduct a field validation study in 2006. A draft ASTM practice describing use of the Accu Core sampler is being prepared. An update on the status of the ASTM practice is given in this report.« less
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NEW SOIL VOC Samplers: EN Core AND ACCU Core SAMPLING/STORAGE DEVICES FOR VOC ANALYSIS
2006Co-Authors: Susan S Sorini, John F Schabron, Joseph F RovaniAbstract:Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An ASTM International (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis and specifies sample storage in the En Core sampler at 4 {+-} 2 C for up to 48 hours; -7 to -21 C for up to 14 days; or 4 {+-} 2 C for up to 48 hours followed by storage at -7 to -21 C for up to five days. This report discusses activities performed during the past year to promote and continue acceptance of the En Core Samplers based on their performance to store soil samples for VOC analysis. The En Core sampler is designed to collect soil samples for VOC analysis at the soil surface. To date, a samplingmore » tool for collecting and storing subsurface soil samples for VOC analysis is not available. Development of a subsurface VOC sampling/storage device was initiated in 1999. This device, which is called the Accu Core{trademark} sampler, is designed so that a soil sample can be collected below the surface using a dual-tube penetrometer and transported to the laboratory for analysis in the same container. Laboratory testing of the current Accu Core design shows that the device holds low-level concentrations of VOCs in soil samples during 48-hour storage at 4 {+-} 2 C and that the device is ready for field evaluation to generate additional performance data. This report discusses a field validation exercise that was attempted in Pennsylvania in 2004 and activities being performed to plan and conduct a field validation study in 2006. A draft ASTM practice describing use of the Accu Core sampler is being prepared. An update on the status of the ASTM practice is given in this report.« less
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Validation of a New Soil VOC Sampler: Revision of ASTM Practice D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, and Development of a Subsurface Sampling/Storage Device fo
2003Co-Authors: Susan S Sorini, John F Schabron, Joseph F RovaniAbstract:Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An American Society for Testing and Materials (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis. To support the ASTM practice, a study was performed to estimate the precision of the performance of the 5-gram and 25-gram En Core Samplers to store soil samples spiked with low concentrations of VOCs. This report discusses revision of ASTM Practice D 6418 to include information on the precision of the En Core devices and to reference an ASTM research report on the precision study. This report also discusses revision of the ASTM practice to list storage at -12 {+-} 2 C for up to 14 days and at 4 {+-} 2 C for up to 48 hours followed by storage at -12 {+-} 2C for up to 5 days as acceptable conditions for samples stored in the En Core devices. Data supporting use of these storage conditions are given in an appendix to the practice and are presented in the research report referenced for the precision study. Prior to this revision, storage in the device was specified at 4 {+-} 2 C for up to 48 hours. The En Core sampler is designed to collect soil samples for VOC analysis at the soil surface. To date, a sampling tool for collecting and storing subsurface soil samples for VOC analysis does not exist. Development of a subsurface VOC sampling/storage device was initiated in 1999. This device, which is called the Accu Core sampler, is designed so that a soil sample can be collected below the surface using a penetrometer and transported to the laboratory for analysis in the same container. During the past year, prototype devices have been tested for their performance in storing soil samples containing low concentrations of VOCs. The Accu Core sampler testing is also described in this report.
Leena Leppänen - One of the best experts on this subject based on the ideXlab platform.
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Measurement inter-comparison of bulk snow density and water equivalent of snow cover with snow Core Samplers
2020Co-Authors: Leena Leppänen, Juan Ignazio Lopez-moreno, Bartłomiej Luks, Ladislav Holko, Ghislain Picard, Alba Sanmiguel-vallelado, Esteban Alonso-gonzález, David Finger, Ali Nadir Arslan, Katalin GillemotAbstract:<p>Manually collected snow data can be considered as ground truth for many applications, such as climatological or hydrological studies. Water equivalent of snow cover (SWE) can be manually measured by using a snow tube or snow cylinder to extract a snow Core and measure the bulk density of the Core by weighing it. Different snow Core Samplers and scales are used, but they all use the same measurement principle. However, there are various sources of uncertainty that have not been quantified in detail. To increase the understanding of these errors, different manual SWE measurement devices used across Europe were evaluated within the framework of the COST Action ES1404 HarmoSnow. Two field campaigns were organized in different environments to quantify uncertainties when measuring snow depth, snow bulk density and SWE with Core Samplers. The 1<sup>st</sup> field campaign in 2017 in Iceland focused on measurement differences attributed to different instrumentation compared with the natural variability in the snowpack, and the 2<sup>nd</sup> field campaign in 2018 in Finland focused on device comparison and on the separation of the different sources of variability. To our knowledge, such a comparison has not previously been conducted in terms of the number of device and different environments.</p><p>During the 1<sup>st</sup> campaign, repeated measurements were taken along two 20 m long snow trenches to distinguish snow variability measured at the plot and at the point scale. The results revealed a much higher variability of SWE at the plot scale, resulting from both natural variability and instrument bias, compared to repeated measurements at the same spot, resulting mostly from error induced by observers or a high variability in the snow depth. Snow Micro Pen sampling showed that the snowpack was very homogeneous for the 2<sup>nd</sup> campaign, which allowed for the disregarding of the natural variability of the snowpack properties and the focus to be on separating between instrumental bias and error induced by observers. Results confirmed that instrumental bias exceeded both the natural variability and the error induced by observers, even when observers performed measurements with snow Core Samplers they were not formally trained on. Under such measurement conditions, the uncertainty in bulk snow density estimation is about 5% for an individual instrument and is close to 10% among different instruments. The results showed that the devices provided slightly different uncertainties since they were designed for different snow conditions. The aim of this comparison was not to provide a definitive estimation of uncertainty for manual SWE measurements, but to illustrate the role of the different uncertainty sources.</p>
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intercomparison of measurements of bulk snow density and water equivalent of snow cover with snow Core Samplers instrumental bias and variability induced by observers
Authorea Preprints, 2019Co-Authors: Ignacio Lopezmoreno, Leena Leppänen, Bartłomiej Luks, Ladislav Holko, Ghislain Picard, David Finger, Ali Nadir Arslan, Alba Sanmiguelvallelado, Esteban Alonsogonzalez, Katalin GillemotAbstract:Manually collected snow data are often considered as ground truth for many applications such as climatological or hydrological studies. However, there are many sources of uncertainty that are not quantified in detail. For the determination of water equivalent of snow cover (SWE), different snow Core Samplers and scales are used, but they are all based on the same measurement principle. We conducted two field campaigns with 9 Samplers commonly used in observational measurements and research in Europe and northern America to better quantify uncertainties when measuring depth, density and SWE with Core Samplers. During the first campaign, as a first approach to distinguish snow variability measured at the plot and at the point scale, repeated measurements were taken along two 20 m long snow pits. The results revealed a much higher variability of SWE at the plot scale (resulting from both natural variability and instrumental bias) compared to repeated measurements at the same spot (resulting mostly from error induced by observers or very small scale variability of snow depth). The exceptionally homogeneous snowpack found in the second campaign permitted to almost neglect the natural variability of the snowpack properties and focus on the separation between instrumental bias and error induced by observers. Under such measurement conditions, the uncertainty in bulk snow density estimation is about 5% for an individual instrument and is close to 10% among different instruments. Results confirmed that instrumental bias exceeded both the natural variability and the error induced by observers, even in the case when observers were not familiar with a given snow Core sampler.
G. R.w. Denton - One of the best experts on this subject based on the ideXlab platform.
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Trace metals in sediments of four harbours in Guam
Marine Pollution Bulletin, 2005Co-Authors: G. R.w. Denton, Lucrina P. Concepcion, H.r. Wood, R. J. MorrisonAbstract:Harbours, because of the associated shipping activi-ties, are often sites of serious marine pollution. As a re-sult of the work of international (e.g., the International Maritime Organization and the United Nations Envi-ronment Program) and national agencies, there have been significant improvements recently in the operations and environments of many harbours, but historical activities have often left a pollution impact in the sedi-ments. Guam (13°28 0 N, 144°45 0 E) has been the major shipping centre in Micronesia for about 400 years, but there have been few studies of the impacts on the coastal environment of such activities. This paper reports the first major study of trace metals in sediments of four harbours in Guam. Users of GuamÕs harbours have included the military (since World War II), commercial shippers, commercial and recreational fishermen, tourist operators (dinner cruises, diving, jet-skiing, sailing, etc.), and the general public. All associated activities have the potential to im-pact on the local marine environment and only in the last 20–30 years have any controls on pollution been introduced. As a result, some contamination of sedi-ments is to be expected, but the extent was unknown be-fore this study. The four harbours (Fig. 1a) were selected on the following basis: Agana Boat Basin (major small boat harbour—5 sites); Outer Apra Harbour (heavily used commercial and military port—30 sites); Agat Marina (newly constructed small boat harbour—4 sites); and Merizo Pier (small boat harbour away from indus-trial activity—5 sites). Sediment samples were collected by scuba divers between May 16 and June 12, 1997. Site selection (Fig. 1b–e) was based primarily on proximity to poten-tial sources of contamination (e.g., storm water outlets, mooring sites, wharves, piers, fueling stations, electrical substations, etc.) along presumed concentration gradi-ents. Site locations were pinpointed using digital ortho-photo imagery maps with reference to prominent landmarks. Samples were collected at depths ranging from 0.5 to 17 m, using stainless steel Core Samplers (5 · 30 cm) fitted with pre-cleaned aluminium liners and Teflon lined plastic end-caps. A slide hammer was used to push each Corer 15–30 cm into the sediment depending on the nature of the underlying substrate. Three Cores were sampled within a 3 m diameter circle at each site, and each Core was analysed separately. Because of difficulties encountered in extracting the charged liners from the body of the Corers, the collected sediments were expelled into clean aluminium liners by inversion, wrapped in aluminium foil and stored on ice. In the laboratory, the entire contents of each liner were dislodged into a glass bowl and thoroughly mixed with a polyethylene spatula following the removal of large rocks, shells and other such bulky materials. Sub-samples for petrographic and particle size analysis were dried at room temperature, and sub-samples for metal analyses were placed in acid cleaned polyethylene vials and dried to constant weight at 60 °C. Residual sediment samples were stored in pre-cleaned glass jars at À20 °C for further analysis if necessary. Petrographic assessment (colour, sorting, dominant constituent identification and particle size) was made on the dried sediments. Sieve shaker analysis produced data on 4 size fractions: >2 mm (gravel); 1–2 mm (very coarse sand); 1 mm–63 lm (coarse to very fine sand);