A data assimilative, coupled physical–biological model for the Coastal Gulf of Alaska     

Jerome Fiechter  Gregoire Broquet  Andrew M. Moore  Hernan G. Arango 《Dynamics of Atmospheres and Oceans》2011,51(3):75-98

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Optimal tuning of a GCM using modern and glacial constraints     

Lauren J. Gregoire  Paul J. Valdes  Antony J. Payne  Ron Kahana 《Climate Dynamics》2011,37(3-4):705-719

In climate models, many parameters used to resolve subgrid scale processes can be adjusted through a tuning exercise to fit the model??s output to target climatologies. We present an objective tuning of a low resolution Atmosphere?COcean General Circulation Model (GCM) called FAMOUS where ten model parameters are varied together using a Latin hypercube sampling method to create an ensemble of 100 models. The target of the tuning consists of a wide range of modern climate diagnostics and also includes glacial tropical sea surface temperature. The ensemble of models created is compared to the target using an Arcsin Mielke score. We investigate how the tuning method used and the addition of glacial constraints impact on the present day and glacial climates of the chosen models. Rather than selecting a single configuration which optimises the metric in all the diagnostics, we obtain a subset of nine ??good?? models which display great differences in their climate but which, in some sense, are all better than the original configuration. In those simulations, the global temperature response to last glacial maximum forcings is enhanced compared to the control simulation and the glacial Atlantic Ocean circulation is more in agreement with observations. Our study demonstrates that selecting a single ??optimal?? configuration, relying only on present day constraints may lead to misrepresenting climates different to that of today.  相似文献   

Stable isotope and mineralogical investigation of the genesis of amethyst geodes in the Los Catalanes gemological district,Uruguay, southernmost Paraná volcanic province     

Lauren C. Duarte  Leo A. Hartmann  Luiz H. Ronchi  Zsolt Berner  Thomas Theye  Hans J. Massonne 《Mineralium Deposita》2011,46(3):239-255

Stable isotopes (C, O, S) and mineralogical studies of the world-class amethyst-geode deposits of the Los Catalanes gemological district, Uruguay, constrain processes operative during mineral deposition. The mineralized basaltic andesites from the Cretaceous Paraná volcanic province are intensely altered to zeolites (clinoptilolite) and clay minerals. Variations in the δ¹⁸O values of silica minerals in geodes (chalcedony, quartz, and amethyst) are much larger and the values generally somewhat lower (21.2–31.5‰) in the Uruguayan deposits than in the Ametista do Sul area of southern Brazil. The range of δ³⁴S values (−15.0 to −0.3‰) of altered basaltic rocks requires (in addition to sulfur of magmatic origin) the involvement of ³⁴S-depleted sedimentary sulfur from bacterial sulfate reduction. The results delimit the mineralizing processes to a post-eruption environment characterized by low temperature and strong interaction of the lava flows with meteoric water.  相似文献   

Time Domain Electromagnetic Soundings for Mapping Sea-Water Intrusion in Monterey County, California   总被引：1，自引：0，他引：1  

Theodore Mills  Pieter Hoekstra  Mark Blohm  Lauren Evans 《Ground water》1988,26(6):771-782

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A geospatial search engine for discovering multi-format geospatial data across the web     

Christopher Bone  Alan Ager  Ken Bunzel  Lauren Tierney 《International Journal of Digital Earth》2016,9(1):47-62

The volume of publically available geospatial data on the web is rapidly increasing due to advances in server-based technologies and the ease at which data can now be created. However, challenges remain with connecting individuals searching for geospatial data with servers and websites where such data exist. The objective of this paper is to present a publically available Geospatial Search Engine (GSE) that utilizes a web crawler built on top of the Google search engine in order to search the web for geospatial data. The crawler seeding mechanism combines search terms entered by users with predefined keywords that identify geospatial data services. A procedure runs daily to update map server layers and metadata, and to eliminate servers that go offline. The GSE supports Web Map Services, ArcGIS services, and websites that have geospatial data for download. We applied the GSE to search for all available geospatial services under these formats and provide search results including the spatial distribution of all obtained services. While enhancements to our GSE and to web crawler technology in general lie ahead, our work represents an important step toward realizing the potential of a publically accessible tool for discovering the global availability of geospatial data.  相似文献   

Diatom assemblages in a reservoir sediment core track land-use changes in the watershed     

Lauren A. Schroeder  Scott C. Martin  G. Jay Kerns  Colleen E. McLean 《Journal of Paleolimnology》2016,55(1):17-33

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Tsunami coastal hazard along the US East Coast from coseismic sources in the Açores convergence zone and the Caribbean arc areas     

Grilli  Stéphan T.  Mohammadpour  Maryam  Schambach  Lauren  Grilli  Annette R. 《Natural Hazards》2022,111(2):1431-1478

Natural Hazards - Tsunami coastal hazard is modeled along the US East Coast (USEC), at a coarse regional (450 m) resolution, from coseismic sources located in the Açores Convergence Zone (ACZ)...  相似文献   

The Effects of Quality Control on Decreasing Error Propagation in the LandScan USA Population Distribution Model: A Case Study of Philadelphia County     

Lauren Patterson  Marie Urban  Aaron Myers  Budhendra Bhaduri  Eddie Bright  Phillip Coleman 《Transactions in GIS》2009,13(2):215-228

LandScan USA is a 90 m population distribution model that is used for a variety of applications, including emergency management. Models should have a measure of accuracy; however, the accuracy of population distribution models is difficult to determine due to the inclusion of multiple input datasets and the lack of quantifiable, observable (validated) data to confirm model output. Validated data enables quantification of: (1) overall model accuracy and (2) changes in model output at different levels of quality control. This article examines the effect of quality control for two national school datasets incorporated as input in LandScan USA for Philadelphia County, Pennsylvania; which had a local, validated school dataset available. The effect of each stage of quality control efforts utilized throughout the LandScan USA process were assessed to determine what level of quality control was required to have a statistically significant change of the model's population distribution. The typical level of quality control for LandScan USA resulted in 36% of schools being moved to the correct location and 20% of missing student enrollments were found, compared to 87% and 98% respectively for the validated dataset. The costs of increasing quality control resulted in a six-fold increase in labor time; however, the additional quality control did not produce statistically significant improvements in the LandScan USA model. Thus, typical quality control efforts for schools in LandScan USA produced a population distribution similar to the validated level of quality control, and can be applied with confidence for policy, planning, and emergency situations.  相似文献   

Diagenetic evolution of lower Jurassic platform carbonates flanking the Tazoult salt wall (Central High Atlas,Morocco)     

Mar Moragas  Vinyet Baqués  Anna Travé  Juan Diego Martín-Martín  Eduard Saura  Gregoire Messager  David Hunt  Jaume Vergés 《Basin Research》2020,32(3):546-566

Platform carbonates diagenesis in salt basins could be complex due to potential alterations of fluids related and non-related to diapirism. This paper presents the diagenetic history of the Hettangian to Pliensbachian platform carbonates from the Tazoult salt wall area (central High Atlas, Morocco). Low structural relief and outcrop conditions allowed to define the entire diagenetic evolution occurred in the High Atlas diapiric basins since early stages of the diapiric activity up to their tectonic inversion. Precipitation of dolomite and calcite from both warmed marine-derived and meteoric fluids characterised diagenetic stages during Pliensbachian, when the carbonate platforms were exposed and karstified. Burial diagenesis occurred from Toarcian to Middle Jurassic, due to changes of salt-induced dynamic related to increase in siliciclastic input, fast diapir rise and rapid burial of Pliensbachian platforms. During this stage, the diapir acted as a physical barrier for fluid circulation between the core and the flanking sediments. In the carbonates and breccias flanking the structures, dolomite and calcite precipitated from basinal brines, whereas carbonate slivers located in the core of the structure, were affected by the circulation of Mn-rich fluids. The final diagenetic event is characterised by the income of meteoric fluids into the system during uplift caused by Alpine orogeny. These results highlight the relevant influence of diapirism on the diagenetic modifications in salt-related basins in terms of diagenetic events and involved fluids.  相似文献   

Effects of gradient,distance, curvature and aspect on steep burned and unburned hillslope soil erosion and deposition   总被引：1，自引：0，他引：1       下载免费PDF全文

Lauren M. Perreault  Elowyn M. Yager  Rolf Aalto 《地球表面变化过程与地形》2017,42(7):1033-1048

Wildfire denudes vegetation and impacts chemical and physical soil properties, which can alter hillslope erosion rates. Post‐wildfire erosion can also contribute disproportionately to long‐term erosion rates and landscape evolution. Post‐fire hillslope erosion rates remain difficult to predict and document at the hillslope scale. Here we use ²¹⁰Pb_aex (lead‐210 mineral‐adsorbed excess) inventories to describe net sediment erosion on steep, convex hillslopes in three basins (unburned, moderately and severely burned) in mountainous central Idaho. We analyzed nearly 300 soil samples for ²¹⁰Pb_aex content with alpha spectrometry and related net sediment erosion to burn severity, aspect, gradient, curvature and distance from ridgetop. We also tested our data against models for advective, linear and non‐linear diffusive erosion. Statistically lower net soil losses on north‐ versus south‐facing unburned hillslopes suggest that greater vegetative cover and soil cohesion on north‐facing slopes decrease erosion. On burned hillslopes, erosion differences between aspects were less apparent and net erosion was more variable, indicating that vegetation influences erosion magnitude and fire drives erosion variability. We estimated net soil losses throughout the length of unburned hillslopes, including through a footslope transition to concave form. In contrast, on burned hillslopes, the subtle shift from convex to concave form was associated with deposition of a post‐fire erosion pulse. Such overall patterns of erosion and deposition are consistent with predictions from a non‐linear diffusion equation. This finding also suggests that concave sections of overall convex hillslopes affect post‐disturbance soil erosion and deposition. Despite these patterns, no strong relationships were evident between local net soil losses and gradient, curvature, distance from ridgetop, or erosion predicted with advection or diffusion equations. The observed relationship between gradient and erosion is therefore likely more complex or stochastic than often described theoretically, especially over relatively short timescales (60–100 years). Copyright © 2016 John Wiley & Sons, Ltd.  相似文献