13 results on '"Lipp, Alex G."'
Search Results
2. Using Convex Optimization to Efficiently Apportion Tracer and Pollutant Sources From Point Concentration Observations.
- Author
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Barnes, Richard and Lipp, Alex G.
- Subjects
DIRECTED acyclic graphs ,POLLUTANTS ,RIVER pollution ,RIVER sediments ,GEOCHEMISTRY - Abstract
Rivers transport elements, minerals, chemicals, and pollutants produced in their upstream basins. A sample from a river is a mixture of all of its upstream sources, making it challenging to pinpoint the contribution from each individual source. Here, we show how a nested sample design and convex optimization can be used to efficiently unmix downstream samples of a well‐mixed, conservative tracer in a steady state system into the contributions of their upstream sources. Our approach is significantly faster than previous methods. We represent the river's sub‐catchments, defined by sampling sites, using a directed acyclic graph. This graph is used to build a convex optimization problem which, thanks to its convexity, can be quickly solved to global optimality—in under a second on desktop hardware for data sets of ∼100 samples or fewer. Uncertainties in the upstream predictions can be generated using Monte Carlo resampling. We provide an open‐source implementation of this approach in Python. The inputs required are straightforward: a table containing sample locations and observed tracer concentrations, along with a D8 flow‐direction raster map. As a case study, we use this method to map the elemental geochemistry of sediment sources for rivers draining the Cairngorms mountains, UK. This method could be extended to non‐conservative and non‐steady state tracers. We also show, theoretically, how multiple tracers could be simultaneously inverted to recover upstream run‐off or erosion rates as well as source concentrations. Overall, this approach can provide valuable insights to researchers in various fields, including water quality, geochemical exploration, geochemistry, hydrology, and wastewater epidemiology. Plain Language Summary: Rivers transport solid and dissolved elements, chemicals, and pollutants from upstream to downstream. Knowing where these elements are coming from, and in what quantities, is useful in targeting environmental protection or learning about the geology and hydrology of an area. However, a single sample of a river can't provide much useful information because all of the different sources have been mixed together by the river. If multiple samples are taken upstream and downstream, we show that a computational technique called convex optimization can be used to "unmix" the river's waters or sediments revealing where the elements have come from. This approach is accurate and fast enough that we can run it thousands of times with small changes to the sampled values to get a sense of the uncertainty. Though we speak about our method in terms of rivers here, it could be useful in other contexts, such as determining where pollutants or tracers of disease outbreaks are entering sewage networks. Key Points: Unmixing sources and magnitudes of tracers from nested concentration measurements in a river basin is a convex optimisation problemWe provide new software that solves this problem very quickly given a D8 raster and some point observations of concentrationThis method can be used to apportion pollution in a river basin and in any geochemistry study that uses a nested sampling design [ABSTRACT FROM AUTHOR]
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- 2024
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3. Towards inverse modeling of landscapes using the Wasserstein distance
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Morris, Matthew J, primary, Lipp, Alex G, additional, and Roberts, Gareth G, additional
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- 2023
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4. Geochemical mapping by unmixing alluvial sediments: An example from northern Australia
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Lipp, Alex G., primary, de Caritat, Patrice, additional, and Roberts, Gareth G., additional
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- 2023
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5. Quantifying excess heavy metal concentrations in drainage basins using conservative mixing models
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Eschenfelder, Jonas, primary, Lipp, Alex G., additional, and Roberts, Gareth G., additional
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- 2023
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6. Towards inverse modeling of landscapes using the Wasserstein distance
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Morris, Matthew James, primary, Lipp, Alex G, additional, and Roberts, Gareth G, additional
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- 2023
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7. Source Region Geochemistry From Unmixing Downstream Sedimentary Elemental Compositions
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Lipp, Alex G., primary, Roberts, Gareth G., additional, Whittaker, Alexander C., additional, Gowing, Charles J. B., additional, and Fernandes, Victoria M., additional
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- 2021
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8. The Sedimentary Geochemistry and Paleoenvironments Project
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Farrell, Úna C., primary, Samawi, Rifaat, additional, Anjanappa, Savitha, additional, Klykov, Roman, additional, Adeboye, Oyeleye O., additional, Agic, Heda, additional, Ahm, Anne‐Sofie C., additional, Boag, Thomas H., additional, Bowyer, Fred, additional, Brocks, Jochen J., additional, Brunoir, Tessa N., additional, Canfield, Donald E., additional, Chen, Xiaoyan, additional, Cheng, Meng, additional, Clarkson, Matthew O., additional, Cole, Devon B., additional, Cordie, David R., additional, Crockford, Peter W., additional, Cui, Huan, additional, Dahl, Tais W., additional, Mouro, Lucas D., additional, Dewing, Keith, additional, Dornbos, Stephen Q., additional, Drabon, Nadja, additional, Dumoulin, Julie A., additional, Emmings, Joseph F., additional, Endriga, Cecilia R., additional, Fraser, Tiffani A., additional, Gaines, Robert R., additional, Gaschnig, Richard M., additional, Gibson, Timothy M., additional, Gilleaudeau, Geoffrey J., additional, Gill, Benjamin C., additional, Goldberg, Karin, additional, Guilbaud, Romain, additional, Halverson, Galen P., additional, Hammarlund, Emma U., additional, Hantsoo, Kalev G., additional, Henderson, Miles A., additional, Hodgskiss, Malcolm S.W., additional, Horner, Tristan J., additional, Husson, Jon M., additional, Johnson, Benjamin, additional, Kabanov, Pavel, additional, Brenhin Keller, C., additional, Kimmig, Julien, additional, Kipp, Michael A., additional, Knoll, Andrew H., additional, Kreitsmann, Timmu, additional, Kunzmann, Marcus, additional, Kurzweil, Florian, additional, LeRoy, Matthew A., additional, Li, Chao, additional, Lipp, Alex G., additional, Loydell, David K., additional, Lu, Xinze, additional, Macdonald, Francis A., additional, Magnall, Joseph M., additional, Mänd, Kaarel, additional, Mehra, Akshay, additional, Melchin, Michael J., additional, Miller, Austin J., additional, Mills, N. Tanner, additional, Mwinde, Chiza N., additional, O'Connell, Brennan, additional, Och, Lawrence M., additional, Ossa Ossa, Frantz, additional, Pagès, Anais, additional, Paiste, Kärt, additional, Partin, Camille A., additional, Peters, Shanan E., additional, Petrov, Peter, additional, Playter, Tiffany L., additional, Plaza‐Torres, Stephanie, additional, Porter, Susannah M., additional, Poulton, Simon W., additional, Pruss, Sara B., additional, Richoz, Sylvain, additional, Ritzer, Samantha R., additional, Rooney, Alan D., additional, Sahoo, Swapan K., additional, Schoepfer, Shane D., additional, Sclafani, Judith A., additional, Shen, Yanan, additional, Shorttle, Oliver, additional, Slotznick, Sarah P., additional, Smith, Emily F., additional, Spinks, Sam, additional, Stockey, Richard G., additional, Strauss, Justin V., additional, Stüeken, Eva E., additional, Tecklenburg, Sabrina, additional, Thomson, Danielle, additional, Tosca, Nicholas J., additional, Uhlein, Gabriel J., additional, Vizcaíno, Maoli N., additional, Wang, Huajian, additional, White, Tristan, additional, Wilby, Philip R., additional, Woltz, Christina R., additional, Wood, Rachel A., additional, Xiang, Lei, additional, Yurchenko, Inessa A., additional, Zhang, Tianran, additional, Planavsky, Noah J., additional, Lau, Kimberly V., additional, Johnston, David T., additional, and Sperling, Erik A., additional
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- 2021
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9. The Sedimentary Geochemistry and Paleoenvironments Project
- Author
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Farrell, Úna C., Samawi, Rifaat, Anjanappa, Savitha, Klykov, Roman, Adeboye, Oyeleye O., Agic, Heda, Ahm, Anne-Sofie C., Boag, Thomas H., Bowyer, Fred, Brocks, Jochen J., Brunoir, Tessa N., Canfield, Donald E., Chen, Xiaoyan, Cheng, Meng, Clarkson, Matthew O., Cole, Devon B., Cordie, David R., Crockford, Peter W., Cui, Huan, Dahl, Tais W., Mouro, Lucas D., Dewing, Keith, Dornbos, Stephen Q., Drabon, Nadja, Dumoulin, Julie A., Emmings, Joseph F., Endriga, Cecilia R., Fraser, Tiffani A., Gaines, Robert R., Gaschnig, Richard M., Gibson, Timothy M., Gilleaudeau, Geoffrey J., Gill, Benjamin C., Goldberg, Karin, Guilbaud, Romain, Halverson, Galen P., Hammarlund, Emma U., Hantsoo, Kalev G., Henderson, Miles A., Hodgskiss, Malcolm S. W., Horner, Tristan J., Husson, Jon M., Johnson, Benjamin, Kabanov, Pavel, Keller, C. Brenhin, Kimmig, Julien, Kipp, Michael A., Knoll, Andrew H., Kreitsmann, Timmu, Kunzmann, Marcus, Kurzweil, Florian, LeRoy, Matthew A., Li, Chao, Lipp, Alex G., Loydell, David K., Lu, Xinze, Macdonald, Francis A., Magnall, Joseph M., Mänd, Kaarel, Mehra, Akshay, Melchin, Michael J., Miller, Austin J., Mills, N. Tanner, Mwinde, Chiza N., O'Connell, Brennan, Och, Lawrence M., Ossa Ossa, Frantz, Pagès, Anais, Paiste, Kärt, Partin, Camille A., Peters, Shanan E., Petrov, Peter, Playter, Tiffany L., Plaza-Torres, Stephanie, Porter, Susannah M., Poulton, Simon W., Pruss, Sara, Richoz, Sylvain, Ritzer, Samantha R., Rooney, Alan D., Sahoo, Swapan K., Schoepfer, Shane D., Sclafani, Judith A., Shen, Yanan, Shorttle, Oliver, Slotznick, Sarah P., Smith, Emily F., Spinks, Sam, Stockey, Richard G., Strauss, Justin V., Stüeken, Eva E., Tecklenburg, Sabrina, Thomson, Danielle, Tosca, Nicholas J., Uhlein, Gabriel J., Vizcaíno, Maoli N., Wang, Huajian, White, Tristan, Wilby, Philip R., Woltz, Christina R., Wood, Rachel A., Xiang, Lei, Yurchenko, Inessa A., Zhang, Tianran, Planavsky, Noah J., Lau, Kimberly V., Johnston, David T., Sperling, Erik A., Farrell, Úna C., Samawi, Rifaat, Anjanappa, Savitha, Klykov, Roman, Adeboye, Oyeleye O., Agic, Heda, Ahm, Anne-Sofie C., Boag, Thomas H., Bowyer, Fred, Brocks, Jochen J., Brunoir, Tessa N., Canfield, Donald E., Chen, Xiaoyan, Cheng, Meng, Clarkson, Matthew O., Cole, Devon B., Cordie, David R., Crockford, Peter W., Cui, Huan, Dahl, Tais W., Mouro, Lucas D., Dewing, Keith, Dornbos, Stephen Q., Drabon, Nadja, Dumoulin, Julie A., Emmings, Joseph F., Endriga, Cecilia R., Fraser, Tiffani A., Gaines, Robert R., Gaschnig, Richard M., Gibson, Timothy M., Gilleaudeau, Geoffrey J., Gill, Benjamin C., Goldberg, Karin, Guilbaud, Romain, Halverson, Galen P., Hammarlund, Emma U., Hantsoo, Kalev G., Henderson, Miles A., Hodgskiss, Malcolm S. W., Horner, Tristan J., Husson, Jon M., Johnson, Benjamin, Kabanov, Pavel, Keller, C. Brenhin, Kimmig, Julien, Kipp, Michael A., Knoll, Andrew H., Kreitsmann, Timmu, Kunzmann, Marcus, Kurzweil, Florian, LeRoy, Matthew A., Li, Chao, Lipp, Alex G., Loydell, David K., Lu, Xinze, Macdonald, Francis A., Magnall, Joseph M., Mänd, Kaarel, Mehra, Akshay, Melchin, Michael J., Miller, Austin J., Mills, N. Tanner, Mwinde, Chiza N., O'Connell, Brennan, Och, Lawrence M., Ossa Ossa, Frantz, Pagès, Anais, Paiste, Kärt, Partin, Camille A., Peters, Shanan E., Petrov, Peter, Playter, Tiffany L., Plaza-Torres, Stephanie, Porter, Susannah M., Poulton, Simon W., Pruss, Sara, Richoz, Sylvain, Ritzer, Samantha R., Rooney, Alan D., Sahoo, Swapan K., Schoepfer, Shane D., Sclafani, Judith A., Shen, Yanan, Shorttle, Oliver, Slotznick, Sarah P., Smith, Emily F., Spinks, Sam, Stockey, Richard G., Strauss, Justin V., Stüeken, Eva E., Tecklenburg, Sabrina, Thomson, Danielle, Tosca, Nicholas J., Uhlein, Gabriel J., Vizcaíno, Maoli N., Wang, Huajian, White, Tristan, Wilby, Philip R., Woltz, Christina R., Wood, Rachel A., Xiang, Lei, Yurchenko, Inessa A., Zhang, Tianran, Planavsky, Noah J., Lau, Kimberly V., Johnston, David T., and Sperling, Erik A.
- Abstract
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Farrell, U. C., Samawi, R., Anjanappa, S., Klykov, R., Adeboye, O. O., Agic, H., Ahm, A.-S. C., Boag, T. H., Bowyer, F., Brocks, J. J., Brunoir, T. N., Canfield, D. E., Chen, X., Cheng, M., Clarkson, M. O., Cole, D. B., Cordie, D. R., Crockford, P. W., Cui, H., Dahl, T. W., Mouro, L. D., Dewing, K., Dornbos, S. Q., Drabon, N., Dumoulin, J. A., Emmings, J. F., Endriga, C. R., Fraser, T. A., Gaines, R. R., Gaschnig, R. M., Gibson, T. M., Gilleaudeau, G. J., Gill, B. C., Goldberg, K., Guilbaud, R., Halverson, G. P., Hammarlund, E. U., Hantsoo, K. G., Henderson, M. A., Hodgskiss, M. S. W., Horner, Tristan J., Husson, J. M., Johnson, B., Kabanov, P., Brenhin K. C., Kimmig, J., Kipp, M. A., Knoll, A. H., Kreitsmann, T., Kunzmann, M., Kurzweil, F., LeRoy, M. A., Li, C., Lipp, A. G., Loydell, D. K., Lu, X., Macdonald, F. A., Magnall, J. M., Mänd, K., Mehra, A., Melchin, M. J., Miller, A. J., Mills, N. T., Mwinde, C. N., O'Connell, B., Och, L. M., Ossa Ossa, F., Pagès, A., Paiste, K., Partin, C. A., Peters, S. E., Petrov, P., Playter, T. L., Plaza-Torres, S., Porter, Susannah M., Poulton, S. W., Pruss, S. B., Richoz, S., Ritzer, S. R., Rooney, A. D., Sahoo, S. K., Schoepfer, S. D., Sclafani, J. A., Shen, Y., Shorttle, O., Slotznick, S. P., Smith, E. F., Spinks, S., Stockey, R. G., Strauss, J. V., Stüeken, E. E., Tecklenburg, S., Thomson, D., Tosca, N. J., Uhlein, G. J., Vizcaíno, M. N., Wang, H., White, T., Wilby, P. R., Woltz, C. R., Wood, R. A., Xiang, L., Yurchenko, I. A., Zhang, T., Planavsky, N. J., Lau, K. V., Johnston, D. T., Sperling, E. A., The Sedimentary Geochemistry and Paleoenvironments Project. Geobiology. 00, (2021): 1– 12,https://doi.org/10.1111/gbi.12462., Geobiology explores how Earth's system has changed over the course of geologic history and how living organisms on this planet are impacted by or are indeed causing these changes. For decades, geologists, paleontologists, and geochemists have generated data to investigate these topics. Foundational efforts in sedimentary geochemistry utilized spreadsheets for data storage and analysis, suitable for several thousand samples, but not practical or scalable for larger, more complex datasets. As results have accumulated, researchers have increasingly gravitated toward larger compilations and statistical tools. New data frameworks have become necessary to handle larger sample sets and encourage more sophisticated or even standardized statistical analyses. In this paper, we describe the Sedimentary Geochemistry and Paleoenvironments Project (SGP; Figure 1), which is an open, community-oriented, database-driven research consortium. The goals of SGP are to (1) create a relational database tailored to the needs of the deep-time (millions to billions of years) sedimentary geochemical research community, including assembling and curating published and associated unpublished data; (2) create a website where data can be retrieved in a flexible way; and (3) build a collaborative consortium where researchers are incentivized to contribute data by giving them priority access and the opportunity to work on exciting questions in group papers. Finally, and more idealistically, the goal was to establish a culture of modern data management and data analysis in sedimentary geochemistry. Relative to many other fields, the main emphasis in our field has been on instrument measurement of sedimentary geochemical data rather than data analysis (compared with fields like ecology, for instance, where the post-experiment ANOVA (analysis of variance) is customary). Thus, the longer-term goal was to build a collaborative environment where geobiologists and geologists can work and learn together to, We thank the donors of The American Chemical Society Petroleum Research Fund for partial support of SGP website development (61017-ND2). EAS is funded by National Science Foundation grant (NSF) EAR-1922966. BGS authors (JE, PW) publish with permission of the Executive Director of the British Geological Survey, UKRI.
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- 2021
10. River Sediment Geochemistry as a Conservative Mixture of Source Regions: Observations and Predictions From the Cairngorms, UK
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Lipp, Alex G., Roberts, Gareth G., Whittaker, Alexander C., Gowing, Charles J.B., Fernandes, Victoria M., Lipp, Alex G., Roberts, Gareth G., Whittaker, Alexander C., Gowing, Charles J.B., and Fernandes, Victoria M.
- Abstract
The elemental composition of sediments in rivers is the product of physical and chemical erosion of rocks, which is then transported across drainage networks. A corollary is that fluvial sedimentary geochemistry can be used to understand geologic, climatic, and geomorphic processes. Here, we predict elemental compositions of river sediments using drainage networks extracted from digital elevation data and erosional models. The Geochemical Baseline Survey of the Environment was used to quantify substrate (i.e., source region) chemistry. Sedimentary compositions in rivers downstream are predicted by formally integrating eroding substrates with respect to distance downstream. Different erosional models, including the Stream Power model and uniform incision rates, are tested. Predictions are tested using a new suite of compositions obtained from fine grained (<150 μm) sediments at 67 sites along the Spey, Dee, Don, Deveron, and Tay rivers, Cairngorms, UK. Results show that sedimentary geochemistry can be predicted using simple models that include the topography of drainage networks and substrate compositions as input. The concentration of numerous elements including Magnesium, Rubidium, Uranium, Potassium, Calcium, Strontium, and Beryllium can be accurately predicted using this simple approach. Predictions are insensitive to the choice of erosional model, which we suggest is a consequence of broadly homogeneous rates of erosion throughout the study area. Principal component analysis of the river geochemical data suggests that the composition of most Cairngorms river sediments can be explained by mafic/felsic provenance and conservative mixing downstream. These results suggest that the elemental composition of river sediments can be accurately predicted using simple erosional models and digital elevation data.
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- 2020
11. Scale‐Dependent Flow Directions of Rivers and the Importance of Subplate Support
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Lipp, Alex G., primary and Roberts, Gareth G., additional
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- 2021
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12. River Sediment Geochemistry as a Conservative Mixture of Source Regions: Observations and Predictions From the Cairngorms, UK
- Author
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Lipp, Alex G., primary, Roberts, Gareth G., additional, Whittaker, Alexander C., additional, Gowing, Charles J. B., additional, and Fernandes, Victoria M., additional
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- 2020
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13. Major Element Composition of Sediments in Terms of Weathering and Provenance: Implications for Crustal Recycling
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Lipp, Alex G., primary, Shorttle, Oliver, additional, Syvret, Frank, additional, and Roberts, Gareth G., additional
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- 2020
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