The national forests (NFs) in the United States are protected areas managed for multiple purposes, and therefore are subject to both natural and anthropogenic disturbances. Monitoring forest changes arising from such disturbances and the post-disturbance recovery processes is essential for assessing the conditions of the NFs and the effectiveness of management approaches. In this study, we used time series stacks of Landsat images (LTSS) to evaluate the dynamics of seven NFs in eastern United States, including the De Soto NF, the Talladega NF, the Francis Marion NF, and the Uwharrie NF in southeastern U.S., and the Chequamegon NF, the Hiawatha NF, and the Superior NF in northern U.S. Each LTSS consisted of 12–14 Landsat images acquired for the same location, spanning from 1984 to 2006 with a nominal interval of one image every 2 years. Each LTSS was analyzed using a vegetation change tracker (VCT) algorithm to map forest disturbance. Accuracy assessments of the derived disturbance maps revealed that they had overall accuracy values of about 80%, with most of the disturbance classes having user's accuracies ranging from 70% to 95%. The producer's accuracies were generally lower, with the majority being in the range between 50% and 70%. While this may suggest that the disturbance maps could slightly underestimate disturbances, a more detailed assessment of the omission errors revealed that the majority of the disagreements were due to minor disturbances like thinning or storm damages that were identified by the image analysts but were not captured by the VCT algorithm.
The derived disturbance year maps revealed that while each of the seven NFs consisted of 90% or more forest land, significant portions of the forests were disturbed since 1984. Mapped disturbances accounted for about 30%–45% of total land area in the four NFs in southeastern U.S. and about 10%–20% in the three NFs in northern U.S. The disturbance rates were generally higher in the buffer zones surrounding each NF, and varied considerably over time. The time series approach employed in this study represents a new approach for monitoring forest resources using the Landsat or similar satellite data records. The disturbance products derived using this approach were spatially explicit and contained much more temporal details than conventional bi-temporal change products, and likely will be found more useful by many users including ecologists and resources managers. The high disturbance rates found in the southeastern U.S. suggest that this region may have a more significant role in modulating the atmospheric carbon budget than currently recognized.
","language":"English","publisher":"Elsevier","doi":"10.1016/j.rse.2008.06.016","issn":"00344257","usgsCitation":"Huang, C., Goward, S., Schleeweis, K., Thomas, N., Masek, J.G., and Zhu, Z., 2009, Dynamics of national forests assessed using the Landsat record: Case studies in eastern United States: Remote Sensing of Environment, v. 113, no. 7, p. 1430-1442, https://doi.org/10.1016/j.rse.2008.06.016.","productDescription":"13 p.","startPage":"1430","endPage":"1442","numberOfPages":"13","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":245679,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":217718,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.rse.2008.06.016"}],"volume":"113","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0434e4b0c8380cd50855","contributors":{"authors":[{"text":"Huang, C.","contributorId":65255,"corporation":false,"usgs":true,"family":"Huang","given":"C.","email":"","affiliations":[],"preferred":false,"id":458182,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Goward, S.N.","contributorId":94514,"corporation":false,"usgs":true,"family":"Goward","given":"S.N.","affiliations":[],"preferred":false,"id":458184,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Schleeweis, K.","contributorId":10258,"corporation":false,"usgs":true,"family":"Schleeweis","given":"K.","affiliations":[],"preferred":false,"id":458180,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Thomas, N.","contributorId":72490,"corporation":false,"usgs":true,"family":"Thomas","given":"N.","email":"","affiliations":[],"preferred":false,"id":458183,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Masek, J. G.","contributorId":105883,"corporation":false,"usgs":true,"family":"Masek","given":"J.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":458185,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Zhu, Z.","contributorId":10898,"corporation":false,"usgs":true,"family":"Zhu","given":"Z.","email":"","affiliations":[],"preferred":false,"id":458181,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70036862,"text":"70036862 - 2009 - THEMIS high-resolution digital terrain: Topographic and thermophysical mapping of Gusev Crater, Mars","interactions":[],"lastModifiedDate":"2012-03-12T17:21:59","indexId":"70036862","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2317,"text":"Journal of Geophysical Research E: Planets","active":true,"publicationSubtype":{"id":10}},"title":"THEMIS high-resolution digital terrain: Topographic and thermophysical mapping of Gusev Crater, Mars","docAbstract":"We discuss a new technique to generate high-resolution digital terrain models (DTMs) and to quantitatively derive and map slope-corrected thermophysical properties such as albedo, thermal inertia, and surface temperatures. This investigation is a continuation of work started by Kirk et al. (2005), who empirically deconvolved Thermal Emission Imaging System (THEMIS) visible and thermal infrared data of this area, isolating topographic information that produced an accurate DTM. Surface temperatures change as a function of many variables such as slope, albedo, thermal inertia, time, season, and atmospheric opacity. We constrain each of these variables to construct a DTM and maps of slope-corrected albedo, slope- and albedo-corrected thermal inertia, and surface temperatures across the scene for any time of day or year and at any atmospheric opacity. DTMs greatly facilitate analyses of the Martian surface, and the MOLA global data set is not finely scaled enough (128 pixels per degree, ???0.5 km per pixel near the equator) to be combined with newer data sets (e.g., High Resolution Imaging Science Experiment, Context Camera, and Compact Reconnaissance Imaging Spectrometer for Mars at ???0.25, ???6, and ???20 m per pixel, respectively), so new techniques to derive high-resolution DTMs are always being explored. This paper discusses our technique of combining a set of THEMIS visible and thermal infrared observations such that albedo and thermal inertia variations within the scene are eliminated and only topographic variations remain. This enables us to produce a high-resolution DTM via photoclinometry techniques that are largely free of albedo-induced errors. With this DTM, THEMIS observations, and a subsurface thermal diffusion model, we generate slope-corrected maps of albedo, thermal inertia, and surface temperatures. In addition to greater accuracy, these products allow thermophysical properties to be directly compared with topography.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Geophysical Research E: Planets","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1029/2008JE003292","issn":"01480227","usgsCitation":"Cushing, G., Titus, T., Soderblom, L., and Kirk, R.L., 2009, THEMIS high-resolution digital terrain: Topographic and thermophysical mapping of Gusev Crater, Mars: Journal of Geophysical Research E: Planets, v. 114, no. 7, https://doi.org/10.1029/2008JE003292.","costCenters":[],"links":[{"id":217687,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1029/2008JE003292"},{"id":245647,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"114","issue":"7","noUsgsAuthors":false,"publicationDate":"2009-07-15","publicationStatus":"PW","scienceBaseUri":"505ba383e4b08c986b31fd2c","contributors":{"authors":[{"text":"Cushing, G.E.","contributorId":56778,"corporation":false,"usgs":true,"family":"Cushing","given":"G.E.","email":"","affiliations":[],"preferred":false,"id":458177,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Titus, T.N.","contributorId":102615,"corporation":false,"usgs":true,"family":"Titus","given":"T.N.","email":"","affiliations":[],"preferred":false,"id":458179,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Soderblom, L.A. 0000-0002-0917-853X","orcid":"https://orcid.org/0000-0002-0917-853X","contributorId":6139,"corporation":false,"usgs":true,"family":"Soderblom","given":"L.A.","affiliations":[],"preferred":false,"id":458176,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kirk, R. L.","contributorId":94698,"corporation":false,"usgs":true,"family":"Kirk","given":"R.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":458178,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70036860,"text":"70036860 - 2009 - Co-seismic ruptures of the 12 May 2008, Ms 8.0 Wenchuan earthquake, Sichuan: East-west crustal shortening on oblique, parallel thrusts along the eastern edge of Tibet","interactions":[],"lastModifiedDate":"2012-03-12T17:21:59","indexId":"70036860","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1427,"text":"Earth and Planetary Science Letters","active":true,"publicationSubtype":{"id":10}},"title":"Co-seismic ruptures of the 12 May 2008, Ms 8.0 Wenchuan earthquake, Sichuan: East-west crustal shortening on oblique, parallel thrusts along the eastern edge of Tibet","docAbstract":"The Ms 8.0, Wenchuan earthquake, which devastated the mountainous western rim of the Sichuan basin in central China, produced a surface rupture over 200??km-long with oblique thrust/dextral slip and maximum scarp heights of ~ 10??m. It thus ranks as one of the world's largest continental mega-thrust events in the last 150??yrs. Field investigation shows clear surface breaks along two of the main branches of the NE-trending Longmen Shan thrust fault system. The principal rupture, on the NW-dipping Beichuan fault, displays nearly equal amounts of thrust and right-lateral slip. Basin-ward of this rupture, another continuous surface break is observed for over 70??km on the parallel, more shallowly NW-dipping Pengguan fault. Slip on this latter fault was pure thrusting, with a maximum scarp height of ~ 3.5??m. This is one of the very few reported instances of crustal-scale co-seismic slip partitioning on parallel thrusts. This out-of-sequence event, with distributed surface breaks on crustal mega-thrusts, highlights regional, ~ EW-directed, present day crustal shortening oblique to the Longmen Shan margin of Tibet. The long rupture and large offsets with strong horizontal shortening that characterize the Wenchuan earthquake herald a re-evaluation of tectonic models anticipating little or no active shortening of the upper crust along this edge of the plateau, and require a re-assessment of seismic hazard along potentially under-rated active faults across the densely populated western Sichuan basin and mountains. ?? 2009 Elsevier B.V.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Earth and Planetary Science Letters","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/j.epsl.2009.07.017","issn":"0012821X","usgsCitation":"Liu-Zeng, J., Zhang, Z., Wen, L., Tapponnier, P., Sun, J., Xing, X., Hu, G., Xu, Q., Zeng, L., Ding, L., Ji, C., Hudnut, K., and van der Woerd, J., 2009, Co-seismic ruptures of the 12 May 2008, Ms 8.0 Wenchuan earthquake, Sichuan: East-west crustal shortening on oblique, parallel thrusts along the eastern edge of Tibet: Earth and Planetary Science Letters, v. 286, no. 3-4, p. 355-370, https://doi.org/10.1016/j.epsl.2009.07.017.","startPage":"355","endPage":"370","numberOfPages":"16","costCenters":[],"links":[{"id":476250,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://doi.org/10.1016/j.epsl.2009.07.017","text":"External Repository"},{"id":245617,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":217660,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.epsl.2009.07.017"}],"volume":"286","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f67be4b0c8380cd4c7be","contributors":{"authors":[{"text":"Liu-Zeng, J.","contributorId":87397,"corporation":false,"usgs":true,"family":"Liu-Zeng","given":"J.","email":"","affiliations":[],"preferred":false,"id":458167,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Zhang, Z.","contributorId":47505,"corporation":false,"usgs":true,"family":"Zhang","given":"Z.","email":"","affiliations":[],"preferred":false,"id":458163,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wen, L.","contributorId":90142,"corporation":false,"usgs":true,"family":"Wen","given":"L.","email":"","affiliations":[],"preferred":false,"id":458168,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Tapponnier, P.","contributorId":47616,"corporation":false,"usgs":true,"family":"Tapponnier","given":"P.","email":"","affiliations":[],"preferred":false,"id":458164,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Sun, Jielun","contributorId":33443,"corporation":false,"usgs":true,"family":"Sun","given":"Jielun","email":"","affiliations":[],"preferred":false,"id":458161,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Xing, X.","contributorId":8704,"corporation":false,"usgs":true,"family":"Xing","given":"X.","email":"","affiliations":[],"preferred":false,"id":458157,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Hu, G.","contributorId":42465,"corporation":false,"usgs":true,"family":"Hu","given":"G.","email":"","affiliations":[],"preferred":false,"id":458162,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Xu, Q.","contributorId":92084,"corporation":false,"usgs":true,"family":"Xu","given":"Q.","email":"","affiliations":[],"preferred":false,"id":458169,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Zeng, L.","contributorId":56483,"corporation":false,"usgs":true,"family":"Zeng","given":"L.","email":"","affiliations":[],"preferred":false,"id":458165,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Ding, L.","contributorId":61674,"corporation":false,"usgs":true,"family":"Ding","given":"L.","email":"","affiliations":[],"preferred":false,"id":458166,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Ji, C.","contributorId":31093,"corporation":false,"usgs":true,"family":"Ji","given":"C.","email":"","affiliations":[],"preferred":false,"id":458160,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Hudnut, K.W.","contributorId":25179,"corporation":false,"usgs":true,"family":"Hudnut","given":"K.W.","email":"","affiliations":[],"preferred":false,"id":458159,"contributorType":{"id":1,"text":"Authors"},"rank":12},{"text":"van der Woerd, J.","contributorId":25017,"corporation":false,"usgs":true,"family":"van der Woerd","given":"J.","email":"","affiliations":[],"preferred":false,"id":458158,"contributorType":{"id":1,"text":"Authors"},"rank":13}]}} ,{"id":70036859,"text":"70036859 - 2009 - Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: Modeling groundwater flow in the Shenandoah Valley (USA)","interactions":[],"lastModifiedDate":"2018-10-12T10:22:32","indexId":"70036859","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1923,"text":"Hydrogeology Journal","active":true,"publicationSubtype":{"id":10}},"title":"Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: Modeling groundwater flow in the Shenandoah Valley (USA)","docAbstract":"A numerical representation that explicitly represents the generalized three-dimensional anisotropy of folded fractured-sedimentary rocks in a groundwater model best reproduces the salient features of the flow system in the Shenandoah Valley, USA. This conclusion results from a comparison of four alternative representations of anisotropy in which the hydraulic-conductivity tensor represents the bedrock structure as (model A) anisotropic with variable strikes and dips, (model B) horizontally anisotropic with a uniform strike, (model C) horizontally anisotropic with variable strikes, and (model D) isotropic. Simulations using the US Geological Survey groundwater flow and transport model SUTRA are based on a representation of hydraulic conductivity that conforms to bedding planes in a three-dimensional structural model of the valley that duplicates the pattern of folded sedimentary rocks. In the most general representation, (model A), the directions of maximum and medium hydraulic conductivity conform to the strike and dip of bedding, respectively, while the minimum hydraulic-conductivity direction is perpendicular to bedding. Model A produced a physically realistic flow system that reflects the underlying bedrock structure, with a flow field that is significantly different from those produced by the other three models.
The reactive transport of U(VI) in a well-characterized shallow alluvial aquifer at a former U(VI) mill located near Naturita, CO, was predicted for comparative purposes using a surface complexation model (SCM) and a constant K d approach to simulate U(VI) adsorption. The ground water at the site had U(VI) concentrations that ranged from 0.01 to 20 µM, alkalinities that ranged from 2.5 to 18 meq/L, and a nearly constant pH of 7.1. The SCM used to simulate U(VI) adsorption was previously determined independently using laboratory batch adsorption experiments. Simulations obtained using the SCM approach were compared with simulations that used a constant K d approach to simulate adsorption using previously determined site-specific K d values. In both cases, the ground water flow and transport models used a conceptual model that was previously calibrated to a chloride plume present at the site. Simulations with the SCM approach demonstrated that the retardation factor varied temporally and spatially because of the differential transport of alkalinity and dissolved U(VI) and the nonlinearity of the U(VI) adsorption. The SCM model also simulated a prolonged slow decline in U(VI) concentration, which was not simulated using a constant K d model. Simulations using the SCM approach and the constant K d approach were similar after 20 years of transport but diverged significantly after 60 years. The simulations demonstrate the need for site-specific geochemical information on U(VI) adsorption to produce credible simulations of future transport.
","language":"English","publisher":"Springer","doi":"10.1007/s10230-009-0064-x","issn":"10259112","usgsCitation":"Curtis, G., Kohler, M., and Davis, J., 2009, Comparing approaches for simulating the reactive transport of U(VI) in ground water: Mine Water and the Environment, v. 28, no. 2, p. 84-93, https://doi.org/10.1007/s10230-009-0064-x.","productDescription":"10 p.","startPage":"84","endPage":"93","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":216793,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s10230-009-0064-x"},{"id":244685,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"28","issue":"2","noUsgsAuthors":false,"publicationDate":"2009-02-20","publicationStatus":"PW","scienceBaseUri":"5059f831e4b0c8380cd4cf2a","contributors":{"authors":[{"text":"Curtis, G.P.","contributorId":65619,"corporation":false,"usgs":true,"family":"Curtis","given":"G.P.","email":"","affiliations":[],"preferred":false,"id":445117,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kohler, M.","contributorId":32694,"corporation":false,"usgs":true,"family":"Kohler","given":"M.","affiliations":[],"preferred":false,"id":445116,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Davis, J.A.","contributorId":71694,"corporation":false,"usgs":true,"family":"Davis","given":"J.A.","email":"","affiliations":[],"preferred":false,"id":445118,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70034289,"text":"70034289 - 2009 - Ecology and the ratchet of events: Climate variability, niche dimensions, and species distributions","interactions":[],"lastModifiedDate":"2012-03-12T17:21:46","indexId":"70034289","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"Ecology and the ratchet of events: Climate variability, niche dimensions, and species distributions","docAbstract":"Climate change in the coming centuries will be characterized by interannual, decadal, and multidecadal fluctuations superimposed on anthropogenic trends. Predicting ecological and biogeographic responses to these changes constitutes an immense challenge for ecologists. Perspectives from climatic and ecological history indicate that responses will be laden with contingencies, resulting from episodic climatic events interacting with demographic and colonization events. This effect is compounded by the dependency of environmental sensitivity upon life-stage for many species. Climate variables often used in empirical niche models may become decoupled from the proximal variables that directly influence individuals and populations. Greater predictive capacity, and morefundamental ecological and biogeographic understanding, will come from integration of correlational niche modeling with mechanistic niche modeling, dynamic ecological modeling, targeted experiments, and systematic observations of past and present patterns and dynamics.","largerWorkTitle":"Proceedings of the National Academy of Sciences of the United States of America","language":"English","doi":"10.1073/pnas.0901644106","issn":"00278424","usgsCitation":"Jackson, S., Betancourt, J., Booth, R., and Gray, S., 2009, Ecology and the ratchet of events: Climate variability, niche dimensions, and species distributions, in Proceedings of the National Academy of Sciences of the United States of America, v. 106, no. SUPPL. 2, p. 19685-19692, https://doi.org/10.1073/pnas.0901644106.","startPage":"19685","endPage":"19692","numberOfPages":"8","costCenters":[],"links":[{"id":476235,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/2780932","text":"External Repository"},{"id":216734,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1073/pnas.0901644106"},{"id":244620,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"106","issue":"SUPPL. 2","noUsgsAuthors":false,"publicationDate":"2009-11-17","publicationStatus":"PW","scienceBaseUri":"505a056ce4b0c8380cd50dc5","contributors":{"authors":[{"text":"Jackson, S.T.","contributorId":90072,"corporation":false,"usgs":true,"family":"Jackson","given":"S.T.","email":"","affiliations":[],"preferred":false,"id":445102,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Betancourt, J.L. 0000-0002-7165-0743","orcid":"https://orcid.org/0000-0002-7165-0743","contributorId":87505,"corporation":false,"usgs":true,"family":"Betancourt","given":"J.L.","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":445101,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Booth, R.K.","contributorId":47122,"corporation":false,"usgs":true,"family":"Booth","given":"R.K.","email":"","affiliations":[],"preferred":false,"id":445100,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Gray, S.T.","contributorId":19680,"corporation":false,"usgs":true,"family":"Gray","given":"S.T.","email":"","affiliations":[],"preferred":false,"id":445099,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70035657,"text":"70035657 - 2009 - Effects of experimental water table and temperature manipulations on ecosystem CO2 fluxes in an Alaskan rich fen","interactions":[],"lastModifiedDate":"2012-03-12T17:21:52","indexId":"70035657","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1478,"text":"Ecosystems","active":true,"publicationSubtype":{"id":10}},"title":"Effects of experimental water table and temperature manipulations on ecosystem CO2 fluxes in an Alaskan rich fen","docAbstract":"Peatlands store 30% of the world's terrestrial soil carbon (C) and those located at northern latitudes are expected to experience rapid climate warming. We monitored growing season carbon dioxide (CO2) fluxes across a factorial design of in situ water table (control, drought, and flooded plots) and soil warming (control vs. warming via open top chambers) treatments for 2 years in a rich fen located just outside the Bonanza Creek Experimental Forest in interior Alaska. The drought (lowered water table position) treatment was a weak sink or small source of atmospheric CO2 compared to the moderate atmospheric CO2 sink at our control. This change in net ecosystem exchange was due to lower gross primary production and light-saturated photosynthesis rather than increased ecosystem respiration. The flooded (raised water table position) treatment was a greater CO2 sink in 2006 due largely to increased early season gross primary production and higher light-saturated photosynthesis. Although flooding did not have substantial effects on rates of ecosystem respiration, this water table treatment had lower maximum respiration rates and a higher temperature sensitivity of ecosystem respiration than the control plot. Surface soil warming increased both ecosystem respiration and gross primary production by approximately 16% compared to control (ambient temperature) plots, with no net effect on net ecosystem exchange. Results from this rich fen manipulation suggest that fast responses to drought will include reduced ecosystem C storage driven by plant stress, whereas inundation will increase ecosystem C storage by stimulating plant growth. ?? 2009 Springer Science+Business Media, LLC.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Ecosystems","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1007/s10021-009-9292-y","issn":"14329840","usgsCitation":"Chivers, M., Turetsky, M., Waddington, J., Harden, J., and McGuire, A., 2009, Effects of experimental water table and temperature manipulations on ecosystem CO2 fluxes in an Alaskan rich fen: Ecosystems, v. 12, no. 8, p. 1329-1342, https://doi.org/10.1007/s10021-009-9292-y.","startPage":"1329","endPage":"1342","numberOfPages":"14","costCenters":[],"links":[{"id":216071,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s10021-009-9292-y"},{"id":243913,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"12","issue":"8","noUsgsAuthors":false,"publicationDate":"2009-10-31","publicationStatus":"PW","scienceBaseUri":"505a06e7e4b0c8380cd5148a","contributors":{"authors":[{"text":"Chivers, M.R.","contributorId":96505,"corporation":false,"usgs":true,"family":"Chivers","given":"M.R.","email":"","affiliations":[],"preferred":false,"id":451702,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Turetsky, M.R.","contributorId":107470,"corporation":false,"usgs":true,"family":"Turetsky","given":"M.R.","email":"","affiliations":[],"preferred":false,"id":451704,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Waddington, J. M.","contributorId":105938,"corporation":false,"usgs":false,"family":"Waddington","given":"J. M.","affiliations":[],"preferred":false,"id":451703,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Harden, J.W. 0000-0002-6570-8259","orcid":"https://orcid.org/0000-0002-6570-8259","contributorId":38585,"corporation":false,"usgs":true,"family":"Harden","given":"J.W.","affiliations":[],"preferred":false,"id":451701,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"McGuire, A. D.","contributorId":16552,"corporation":false,"usgs":true,"family":"McGuire","given":"A. D.","affiliations":[],"preferred":false,"id":451700,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70035971,"text":"70035971 - 2009 - Predicting the biological condition of streams: Use of geospatial indicators of natural and anthropogenic characteristics of watersheds","interactions":[],"lastModifiedDate":"2012-03-12T17:21:50","indexId":"70035971","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1552,"text":"Environmental Monitoring and Assessment","onlineIssn":"1573-2959","printIssn":"0167-6369","active":true,"publicationSubtype":{"id":10}},"title":"Predicting the biological condition of streams: Use of geospatial indicators of natural and anthropogenic characteristics of watersheds","docAbstract":"We developed and evaluated empirical models to predict biological condition of wadeable streams in a large portion of the eastern USA, with the ultimate goal of prediction for unsampled basins. Previous work had classified (i.e., altered vs. unaltered) the biological condition of 920 streams based on a biological assessment of macroinvertebrate assemblages. Predictor variables were limited to widely available geospatial data, which included land cover, topography, climate, soils, societal infrastructure, and potential hydrologic modification. We compared the accuracy of predictions of biological condition class based on models with continuous and binary responses. We also evaluated the relative importance of specific groups and individual predictor variables, as well as the relationships between the most important predictors and biological condition. Prediction accuracy and the relative importance of predictor variables were different for two subregions for which models were created. Predictive accuracy in the highlands region improved by including predictors that represented both natural and human activities. Riparian land cover and road-stream intersections were the most important predictors. In contrast, predictive accuracy in the lowlands region was best for models limited to predictors representing natural factors, including basin topography and soil properties. Partial dependence plots revealed complex and nonlinear relationships between specific predictors and the probability of biological alteration. We demonstrate a potential application of the model by predicting biological condition in 552 unsampled basins across an ecoregion in southeastern Wisconsin (USA). Estimates of the likelihood of biological condition of unsampled streams could be a valuable tool for screening large numbers of basins to focus targeted monitoring of potentially unaltered or altered stream segments. ?? Springer Science+Business Media B.V. 2008.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Environmental Monitoring and Assessment","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1007/s10661-008-0256-z","issn":"01676369","usgsCitation":"Carlisle, D., Falcone, J., and Meador, M.R., 2009, Predicting the biological condition of streams: Use of geospatial indicators of natural and anthropogenic characteristics of watersheds: Environmental Monitoring and Assessment, v. 151, no. 1-4, p. 143-160, https://doi.org/10.1007/s10661-008-0256-z.","startPage":"143","endPage":"160","numberOfPages":"18","costCenters":[],"links":[{"id":216148,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s10661-008-0256-z"},{"id":243997,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"151","issue":"1-4","noUsgsAuthors":false,"publicationDate":"2008-05-21","publicationStatus":"PW","scienceBaseUri":"505a81cde4b0c8380cd7b738","contributors":{"authors":[{"text":"Carlisle, D.M.","contributorId":81059,"corporation":false,"usgs":true,"family":"Carlisle","given":"D.M.","email":"","affiliations":[],"preferred":false,"id":453403,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Falcone, J.","contributorId":20548,"corporation":false,"usgs":true,"family":"Falcone","given":"J.","email":"","affiliations":[],"preferred":false,"id":453401,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Meador, M. R.","contributorId":74400,"corporation":false,"usgs":true,"family":"Meador","given":"M.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":453402,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70036576,"text":"70036576 - 2009 - Detection and attribution of streamflow timing changes to climate change in the Western United States","interactions":[],"lastModifiedDate":"2012-03-12T17:22:01","indexId":"70036576","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2216,"text":"Journal of Climate","active":true,"publicationSubtype":{"id":10}},"title":"Detection and attribution of streamflow timing changes to climate change in the Western United States","docAbstract":"This article applies formal detection and attribution techniques to investigate the nature of observed shifts in the timing of streamflow in the western United States. Previous studies have shown that the snow hydrology of the western United States has changed in the second half of the twentieth century. Such changes manifest themselves in the form of more rain and less snow, in reductions in the snow water contents, and in earlier snowmelt and associated advances in streamflow \"center\" timing (the day in the \"water-year\" on average when half the water-year flow at a point has passed). However, with one exception over a more limited domain, no other study has attempted to formally attribute these changes to anthropogenic increases of greenhouse gases in the atmosphere. Using the observations together with a set of global climate model simulations and a hydrologic model (applied to three major hydrological regions of the western United States_the California region, the upper Colorado River basin, and the Columbia River basin), it is found that the observed trends toward earlier \"center\" timing of snowmelt-driven streamflows in the western United States since 1950 are detectably different from natural variability (significant at the p < 0.05 level). Furthermore, the nonnatural parts of these changes can be attributed confidently to climate changes induced by anthropogenic greenhouse gases, aerosols, ozone, and land use. The signal from the Columbia dominates the analysis, and it is the only basin that showed a detectable signal when the analysis was performed on individual basins. It should be noted that although climate change is an important signal, other climatic processes have also contributed to the hydrologic variability of large basins in the western United States. ?? 2009 American Meteorological Society.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Climate","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1175/2009JCLI2470.1","issn":"08948755","usgsCitation":"Hidalgo, H., Das, T., Dettinger, M.D., Cayan, D., Pierce, D., Barnett, T., Bala, G., Mirin, A., Wood, A., Bonfils, C., Santer, B., and Nozawa, T., 2009, Detection and attribution of streamflow timing changes to climate change in the Western United States: Journal of Climate, v. 22, no. 13, p. 3838-3855, https://doi.org/10.1175/2009JCLI2470.1.","startPage":"3838","endPage":"3855","numberOfPages":"18","costCenters":[],"links":[{"id":476205,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1175/2009jcli2470.1","text":"Publisher Index Page"},{"id":217524,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1175/2009JCLI2470.1"},{"id":245477,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"13","noUsgsAuthors":false,"publicationDate":"2009-07-01","publicationStatus":"PW","scienceBaseUri":"5059ff65e4b0c8380cd4f179","contributors":{"authors":[{"text":"Hidalgo, H.G.","contributorId":81229,"corporation":false,"usgs":true,"family":"Hidalgo","given":"H.G.","email":"","affiliations":[],"preferred":false,"id":456818,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Das, T.","contributorId":99383,"corporation":false,"usgs":true,"family":"Das","given":"T.","email":"","affiliations":[],"preferred":false,"id":456823,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Dettinger, M. D. 0000-0002-7509-7332","orcid":"https://orcid.org/0000-0002-7509-7332","contributorId":93069,"corporation":false,"usgs":false,"family":"Dettinger","given":"M.","middleInitial":"D.","affiliations":[{"id":16196,"text":"Scripps Institution of Oceanography, La Jolla, CA","active":true,"usgs":false}],"preferred":false,"id":456821,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Cayan, D.R.","contributorId":25961,"corporation":false,"usgs":false,"family":"Cayan","given":"D.R.","email":"","affiliations":[{"id":16196,"text":"Scripps Institution of Oceanography, La Jolla, CA","active":true,"usgs":false}],"preferred":false,"id":456814,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Pierce, D.W.","contributorId":23342,"corporation":false,"usgs":true,"family":"Pierce","given":"D.W.","email":"","affiliations":[],"preferred":false,"id":456813,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Barnett, T.P.","contributorId":54763,"corporation":false,"usgs":true,"family":"Barnett","given":"T.P.","email":"","affiliations":[],"preferred":false,"id":456817,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Bala, G.","contributorId":86983,"corporation":false,"usgs":true,"family":"Bala","given":"G.","email":"","affiliations":[],"preferred":false,"id":456820,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Mirin, A.","contributorId":104294,"corporation":false,"usgs":true,"family":"Mirin","given":"A.","affiliations":[],"preferred":false,"id":456824,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Wood, A.W.","contributorId":43542,"corporation":false,"usgs":true,"family":"Wood","given":"A.W.","email":"","affiliations":[],"preferred":false,"id":456815,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Bonfils, Celine","contributorId":51542,"corporation":false,"usgs":true,"family":"Bonfils","given":"Celine","email":"","affiliations":[],"preferred":false,"id":456816,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Santer, B.D.","contributorId":95702,"corporation":false,"usgs":true,"family":"Santer","given":"B.D.","email":"","affiliations":[],"preferred":false,"id":456822,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Nozawa, T.","contributorId":83345,"corporation":false,"usgs":true,"family":"Nozawa","given":"T.","email":"","affiliations":[],"preferred":false,"id":456819,"contributorType":{"id":1,"text":"Authors"},"rank":12}]}} ,{"id":70034264,"text":"70034264 - 2009 - Halogen degassing during ascent and eruption of water-poor basaltic magma","interactions":[],"lastModifiedDate":"2017-10-25T12:21:50","indexId":"70034264","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Halogen degassing during ascent and eruption of water-poor basaltic magma","docAbstract":"A study of volcanic gas composition and matrix glass volatile concentrations has allowed a model for halogen degassing to be formulated for K??lauea Volcano, Hawai'i. Volcanic gases emitted during 2004-2005 were characterised by a molar SO2/HCl of 10-64, with a mean of 33; and a molar HF/HCl of 0-5, with a mean of 1.0 (from approximately 2500 measurements). The HF/HCl ratio was more variable than the SO2/HCl ratio, and the two correlate weakly. Variations in ratio took place over rapid timescales (seconds). Matrix glasses of Pele's tears erupted in 2006 have a mean S, Cl and F content of 67, 85 and 173??ppm respectively, but are associated with a large range in S/F. A model is developed that describes the open system degassing of halogens from parental magmas, using the glass data from this study, previously published results and parameterisation of sulphur degassing from previous work. The results illustrate that halogen degassing takes place at pressures of < 1??MPa, equivalent to < ~ 35??m in the conduit. Fluid-melt partition coefficients for Cl and F are low (< 1.5); F only degasses appreciably at < 0.1??MPa above atmospheric pressure, virtually at the top of the magma column. This model reproduces the volcanic gas data and other observations of volcanic activity well and is consistent with other studies of halogen degassing from basaltic magmas. The model suggests that variation in volcanic gas halogen ratios is caused by exsolution and gas-melt separation at low pressures in the conduit. There is no evidence that either diffusive fractionation or near-vent chemical reactions involving halogens is important in the system, although these processes cannot be ruled out. The fluxes of HCl and HF from K??lauea during 2004-5 were ~ 25 and 12??t/d respectively. ?? 2008 Elsevier B.V.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/j.chemgeo.2008.09.022","issn":"00092541","usgsCitation":"Edmonds, M., Gerlach, T., and Herd, R.A., 2009, Halogen degassing during ascent and eruption of water-poor basaltic magma: Chemical Geology, v. 263, no. 1-4, p. 122-130, https://doi.org/10.1016/j.chemgeo.2008.09.022.","productDescription":"9 p.","startPage":"122","endPage":"130","numberOfPages":"9","ipdsId":"IP-012286","costCenters":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"links":[{"id":244746,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":216850,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.chemgeo.2008.09.022"}],"volume":"263","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a2f5ce4b0c8380cd5cd15","contributors":{"authors":[{"text":"Edmonds, M.","contributorId":43547,"corporation":false,"usgs":true,"family":"Edmonds","given":"M.","email":"","affiliations":[],"preferred":false,"id":444981,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gerlach, T.M.","contributorId":38713,"corporation":false,"usgs":true,"family":"Gerlach","given":"T.M.","email":"","affiliations":[],"preferred":false,"id":444980,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Herd, Richard A.","contributorId":95663,"corporation":false,"usgs":true,"family":"Herd","given":"Richard","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":444982,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70035658,"text":"70035658 - 2009 - Seasonal shifts in shelter and microhabitat use of drymarchon couperi (eastern indigo snake) in Georgia","interactions":[],"lastModifiedDate":"2012-03-12T17:21:48","indexId":"70035658","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1337,"text":"Copeia","active":true,"publicationSubtype":{"id":10}},"title":"Seasonal shifts in shelter and microhabitat use of drymarchon couperi (eastern indigo snake) in Georgia","docAbstract":"Drymarchon couperi (Eastern Indigo Snake), a threatened species of the southeastern Coastal Plain of the United States, has experienced population declines because of extensive habitat loss and degradation across its range. In Georgia and northern Florida, the species is associated with longleaf pine habitats that support Gopherus polyphemus (Gopher Tortoise) populations, the burrows of which D. couperi uses for shelter. The extent that D. couperi uses these burrows, in addition to the use of other underground shelters and the microhabitat features associated with these structures is largely unknown. From 2003 through 2004, we conducted a radiotelemetry study of D. couperi (n = 32) to examine use of shelters and microhabitat in Georgia. We used repeated measures regression on a candidate set of models created from a priori hypotheses using principal component scores, derived from analysis of microhabitat data to examine microhabitat use at underground shelters. Proportion of locations recorded underground did not differ seasonally or between sexes. In winter, we recorded >0.90 of underground locations at tortoise burrows. Use of these burrows was less pronounced in spring for males. Females used abandoned tortoise burrows more frequently than males year-round and used them on approximately 0.60 of their underground locations during spring. Microhabitat use at underground shelters was most influenced by season compared to sex, site, or body size. Females in spring and summer used more open microhabitat compared to males, potentially in response to gestation. Our results suggest that the availability of suitable underground shelters, especially G. polyphemus burrows, may be a limiting factor in the northern range of D. couperi, with important implications for its conservation. ?? 2009 by the American Society of Ichthyologists and Herpetologists.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Copeia","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1643/CH-07-171","issn":"00458511","usgsCitation":"Hyslop, N., Cooper, R., and Meyers, J., 2009, Seasonal shifts in shelter and microhabitat use of drymarchon couperi (eastern indigo snake) in Georgia: Copeia, v. 2009, no. 3, p. 458-464, https://doi.org/10.1643/CH-07-171.","startPage":"458","endPage":"464","numberOfPages":"7","costCenters":[],"links":[{"id":243914,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":216072,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1643/CH-07-171"}],"volume":"2009","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b88d7e4b08c986b316bcd","contributors":{"authors":[{"text":"Hyslop, N.L.","contributorId":22066,"corporation":false,"usgs":true,"family":"Hyslop","given":"N.L.","email":"","affiliations":[],"preferred":false,"id":451705,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cooper, R.J.","contributorId":89077,"corporation":false,"usgs":true,"family":"Cooper","given":"R.J.","email":"","affiliations":[],"preferred":false,"id":451707,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Meyers, J.M.","contributorId":54307,"corporation":false,"usgs":true,"family":"Meyers","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":451706,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70036637,"text":"70036637 - 2009 - A revised burial dose estimation procedure for optical dating of youngand modern-age sediments","interactions":[],"lastModifiedDate":"2012-03-12T17:22:01","indexId":"70036637","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3216,"text":"Quaternary Geochronology","active":true,"publicationSubtype":{"id":10}},"title":"A revised burial dose estimation procedure for optical dating of youngand modern-age sediments","docAbstract":"The presence of genuinely zero-age or near-zero-age grains in modern-age and very young samples poses a problem for many existing burial dose estimation procedures used in optical (optically stimulated luminescence, OSL) dating. This difficulty currently necessitates consideration of relatively simplistic and statistically inferior age models. In this study, we investigate the potential for using modified versions of the statistical age models of Galbraith et??al. [Galbraith, R.F., Roberts, R.G., Laslett, G.M., Yoshida, H., Olley, J.M., 1999. Optical dating of single and multiple grains of quartz from Jinmium rock shelter, northern Australia: Part I, experimental design and statistical models. Archaeometry 41, 339-364.] to provide reliable equivalent dose (De) estimates for young and modern-age samples that display negative, zero or near-zero De estimates. For this purpose, we have revised the original versions of the central and minimum age models, which are based on log-transformed De values, so that they can be applied to un-logged De estimates and their associated absolute standard errors. The suitability of these 'un-logged' age models is tested using a series of known-age fluvial samples deposited within two arroyo systems from the American Southwest. The un-logged age models provide accurate burial doses and final OSL ages for roughly three-quarters of the total number of samples considered in this study. Sensitivity tests reveal that the un-logged versions of the central and minimum age models are capable of producing accurate burial dose estimates for modern-age and very young (<350??yr) fluvial samples that contain (i) more than 20% of well-bleached grains in their De distributions, or (ii) smaller sub-populations of well-bleached grains for which the De values are known with high precision. Our results indicate that the original (log-transformed) versions of the central and minimum age models are still preferable for most routine dating applications, since these age models are better suited to the statistical properties of typical single-grain and multi-grain single-aliquot De datasets. However, the unique error properties of modern-age samples, combined with the problems of calculating natural logarithms of negative or zero-Gy De values, mean that the un-logged versions of the central and minimum age models currently offer the most suitable means of deriving accurate burial dose estimates for very young and modern-age samples. ?? 2009 Elsevier Ltd. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Quaternary Geochronology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/j.quageo.2009.02.017","issn":"18711014","usgsCitation":"Arnold, L., Roberts, R., Galbraith, R., and DeLong, S., 2009, A revised burial dose estimation procedure for optical dating of youngand modern-age sediments: Quaternary Geochronology, v. 4, no. 4, p. 306-325, https://doi.org/10.1016/j.quageo.2009.02.017.","startPage":"306","endPage":"325","numberOfPages":"20","costCenters":[],"links":[{"id":217527,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.quageo.2009.02.017"},{"id":245480,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"4","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e561e4b0c8380cd46d0b","contributors":{"authors":[{"text":"Arnold, L.J.","contributorId":99381,"corporation":false,"usgs":true,"family":"Arnold","given":"L.J.","email":"","affiliations":[],"preferred":false,"id":457094,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Roberts, R.G.","contributorId":103905,"corporation":false,"usgs":true,"family":"Roberts","given":"R.G.","email":"","affiliations":[],"preferred":false,"id":457095,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Galbraith, R.F.","contributorId":61272,"corporation":false,"usgs":true,"family":"Galbraith","given":"R.F.","email":"","affiliations":[],"preferred":false,"id":457093,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"DeLong, S.B.","contributorId":29646,"corporation":false,"usgs":true,"family":"DeLong","given":"S.B.","email":"","affiliations":[],"preferred":false,"id":457092,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70036653,"text":"70036653 - 2009 - The morphology and distribution of submerged reefs in the Maui-Nui Complex, Hawaii: New insights into their evolution since the Early Pleistocene","interactions":[],"lastModifiedDate":"2019-04-11T11:55:35","indexId":"70036653","displayToPublicDate":"2009-01-01T00:00:00","publicationYear":"2009","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2667,"text":"Marine Geology","active":true,"publicationSubtype":{"id":10}},"title":"The morphology and distribution of submerged reefs in the Maui-Nui Complex, Hawaii: New insights into their evolution since the Early Pleistocene","docAbstract":"Reef drowning and backstepping have long been recognised as reef responses to sea-level rise on subsiding margins. During the Late Pleistocene (~500–14 ka) Hawaiian reefs grew in response to rapid subsidence and 120 m 100 kyr sea-level cycles, with recent work on the submerged drowned reefs around the big island of Hawaii, and in other locations from the last deglacial, providing insight into reef development under these conditions. In contrast, reefs of the Early Pleistocene (~1.8–0.8 Ma) remain largely unexplored despite developing in response to significantly different 60–70 m 41 kyr sea-level cycles. The Maui-Nui Complex (MNC — forming the islands of Maui, Molokai, Lanai and Kahoolawe), provides a natural laboratory to study reef evolution throughout this time period as recent data indicate the reefs grew from 1.1 to 0.5 Ma. We use new high resolution bathymetric and backscatter data as well as sub-bottom profiling seismic data and field observations from ROV and submersible dives to make a detailed analysis of reef morphology and structure around the MNC. We focus specifically on the south-central region of the complex that provides the best reef exposure and find that the morphology of the reefs varies both regionally and temporally within this region. Barrier and pinnacle features dominate the steeper margins in the north of the study area whilst broad backstepping of the reefs is observed in the south. Within the Au'au channel in the central region between the islands, closely spaced reef and karst morphology indicates repeated subaerial exposure. We propose that this variation in the morphology and structure of the reefs within the MNC has been controlled by three main factors; the subsidence rate of the complex, the amplitude and period of eustatic sea-level cycles, and the slope and continuity of the basement substrate. We provide a model of reef development within the MNC over the last 1.2 Ma highlighting the effect that the interaction of these factors had on reef morphology.
\n\n