The Meteoritical Bulletin,No. 104          下载免费PDF全文

Audrey Bouvier  Jérôme Gattacceca  Carl Agee  Jeffrey Grossman  Knut Metzler 《Meteoritics & planetary science》2017,52(10):2284-2284

Meteoritical Bulletin 104 contains 2279 meteorites including 12 falls (Annama, Cartersville, Creston, Diepenveen, Famenin, Izarzar, Nkayi, Porangaba, San Juan de Ocotán, Trâpe?ng Rôno?s, Xinglongquan, ?d’ár nad Sázavou), with 1847 ordinary chondrites, 138 carbonaceous chondrites, 128 HED achondrites, 38 lunar meteorites, 24 ureilites, 22 Martian meteorites, 19 iron meteorites, 17 primitive achondrites, 14 enstatite chondrites, 10 mesosiderites, 9 Rumuruti chondrites, 5 pallasites, 4 ungrouped achondrites, 2 enstatite achondrites, 1 ungrouped chondrite, and 1 Kakangari chondrite, and with 996 from Antarctica, 790 from Africa, 337 from Asia, 111 from South America, 30 from North America, 11 from Oceania, and 4 from Europe. Note: 1 meteorite from Russia was counted as European.  相似文献   

An application of Boussinesq modeling to Hurricane wave overtopping and inundation     

Patrick J. Lynett  Jeffrey A. Melby 《Ocean Engineering》2010,37(1):135-344

Wave and combined wave-and-surge overtopping was significant across a large portion of the hurricane protection system of New Orleans during Hurricane Katrina. In particular, along the east-facing levees of the Mississippi River-Gulf Outlet (MRGO), the overtopping caused numerous levee breaches. This paper will focus on the MRGO levees, and will attempt to recreate the hydrodynamic conditions during Katrina to provide an estimate of the experienced overtopping rates. Due to the irregular beach profiles leading up to the levees and the general hydrodynamic complexity of the overtopping in this area, a Boussinesq wave model is employed. This model is shown to be accurate for the prediction of waves shoaling and breaking over irregular beach profiles, as well as for the overtopping of levees. With surge levels provided by ADCIRC and nearshore wave heights by STWAVE, the Boussinesq model is used to predict conditions at the MRGO levees for 10 h near the peak of Katrina. The peak simulated overtopping rates correlate well with expected levee damage thresholds and observations of damage in the levee system. Finally, the predicted overtopping rates are utilized to estimate a volumetric flooding rate as a function of time for the entire 20 km stretch of east-facing MRGO levees.  相似文献   

Semipermeable membrane devices link site-specific contaminants to effects: Part 1 - Induction of CYP1A in rainbow trout from contaminants in Prince William Sound, Alaska   总被引：1，自引：1，他引：0  

Springman KR  Short JW  Lindeberg MR  Maselko JM  Khan C  Hodson PV  Rice SD 《Marine environmental research》2008,66(5):477-486

Extracts from semi-permeable membrane devices (SPMDs) deployed on beaches in Prince William Sound (PWS), Alaska, were used to evaluate if complex contaminant mixtures from different sources can be distinguished by the resulting cytochrome P450 1A (CYP1A) activity in exposed test animals. Deployment sites included canneries, salmon hatcheries, and beaches where lingering oil remains from discharges during the 1964 earthquake or the 1989 Exxon Valdez oil spill. Other sites were selected at random to evaluate region-wide contaminant inputs or were located in salmon streams to evaluate contaminants carried and released by migrating salmon carcasses following reproduction. Following standard deployments of approximately 28 d, an aliquot of the accumulated contaminants was intraperitoneally injected without cleanup into juvenile rainbow trout (Oncorhynchus mykiss). After 2 d and 7 d, the activity of CYP1A was measured by the ethoxyresorufin-o-deethylase (EROD) assay. Exposure to extracts from the oiled sites and one hatchery site with numerous creosote pilings elicited strong EROD responses, whereas fish exposed to salmon stream extracts elicited weak but significant responses during late summer compared to late spring. Responses from the other sites were not significant, indicating contaminants from these sources are unlikely to cause CYP1A induction in resident biota. Rather than simply assessing extant contaminants, this method evaluates the potency of the different sites for bringing about aryl hydrocarbon receptor responses in resident biota.  相似文献   

Comparative biomass structure and estimated carbon flow in food webs in the deep Gulf of Mexico     

Gilbert T. Rowe  Chihlin Wei  Clifton Nunnally  Richard Haedrich  Paul Montagna  Jeffrey G. Baguley  Joan M. Bernhard  Mary Wicksten  Archie Ammons  Elva Escobar Briones  Yousra Soliman  Jody W. Deming 《Deep Sea Research Part II: Topical Studies in Oceanography》2008,55(24-26):2699

A budget of the standing stocks and cycling of organic carbon associated with the sea floor has been generated for seven sites across a 3-km depth gradient in the NE Gulf of Mexico, based on a series of reports by co-authors on specific biotic groups or processes. The standing stocks measured at each site were bacteria, Foraminifera, metazoan meiofauna, macrofauna, invertebrate megafauna, and demersal fishes. Sediment community oxygen consumption (SCOC) by the sediment-dwelling organisms was measured at each site using a remotely deployed benthic lander, profiles of oxygen concentration in the sediment pore water of recovered cores and ship-board core incubations. The long-term incorporation and burial of organic carbon into the sediments has been estimated using profiles of a combination of stable and radiocarbon isotopes. The total stock estimates, carbon burial, and the SCOC allowed estimates of living and detrital carbon residence time within the sediments, illustrating that the total biota turns over on time scales of months on the upper continental slope but this is extended to years on the abyssal plain at 3.6 km depth. The detrital carbon turnover is many times longer, however, over the same depths. A composite carbon budget illustrates that total carbon biomass and associated fluxes declined precipitously with increasing depth. Imbalances in the carbon budgets suggest that organic detritus is exported from the upper continental slope to greater depths offshore.The respiration of each individual “size” or functional group within the community has been estimated from allometric models, supplemented by direct measurements in the laboratory. The respiration and standing stocks were incorporated into budgets of carbon flow through and between the different size groups in hypothetical food webs. The decline in stocks and respiration with depth were more abrupt in the larger forms (fishes and megafauna), resulting in an increase in the relative predominance of smaller sizes (bacteria and meiofauna) at depth. Rates and stocks in the deep northern GoM appeared to be comparable to other continental margins where similar comparisons have been made.  相似文献   

On the use of leaf water to determine plant water source: A proof of concept     

Paolo Benettin  Magali F. Nehemy  Lucas A. Cernusak  Ansgar Kahmen  Jeffrey J. McDonnell 《水文研究》2021,35(3):e14073

Source water apportionment studies using the dual isotopes of oxygen and hydrogen have revolutionized our understanding of ecohydrology. But despite these developments—mostly over the past decade—many technical problems still exist in terms of linking xylem water to its soil water and groundwater sources. This is mainly due to sampling issues and possible fractionation of xylem water. Here we explore whether or not leaf water alone can be used to quantify the blend of rainfall event inputs from which the leaf water originates. Leaf water has historically been avoided in plant water uptake studies due to the extreme fractionation processes at the leaf surface. In our proof of concept work we embrace those processes and use the well-known Craig and Gordon model to map leaf water back to its individual precipitation event water sources. We also employ a Bayesian uncertainty estimation approach to quantify source apportionment uncertainties. We show this using a controlled, vegetated lysimeter experiment where we were able to use leaf water to correctly identify the mean seasonal rainfall that was taken up by the plant, with an uncertainty typically within ± 1‰ for δ¹⁸O. While not appropriate for all source water studies, this work shows that leaf water isotope composition may provide a new, relatively un-intrusive method for addressing questions about the plant water source.  相似文献   

Heat flow estimates offshore Haiti in the Caribbean plate     

Frdrique Rolandone  Francis Lucazeau  Jeffrey Poort  Sylvie Leroy 《地学学报》2020,32(3):179-186

Heat‐flow in the Caribbean is poorly known and generally low in the major basins and the Greater Antilles arc, but with some high values in active zones, like in the Cayman trough or in the Lesser Antilles Arc. Here we present new heat‐flow data for offshore Haiti, which is part of the Greater Antilles arc. We obtain new heat‐flow estimates from in situ measurements and Bottom Simulating Reflector (BSR). Both methods suggest a regionally low heat‐flow, respectively 46 ± 7 and 44 ± 12 mW/m², with locally high values exceeding 80 mW/m². The high heat‐flow values are generally located near faults, and could be related to fluid circulations. Our study confirms a low heat‐flow pattern at the scale of the Caribbean but points out the existence of local‐scale variability with high heat‐flow along the northern faults of the Caribbean region.  相似文献   

Improved high-resolution global and regionalized isoscapes of δ18O, δ2H and d-excess in precipitation     

Stefan Terzer-Wassmuth  Leonard I. Wassenaar  Jeffrey M. Welker  Luis J. Araguás-Araguás 《水文研究》2021,35(6):e14254

Patterns of δ¹⁸O and δ²H in Earth's precipitation provide essential scientific data for use in hydrological, climatological, ecological and forensic research. Insufficient global spatial data coverage promulgated the use of gridded datasets employing geostatistical techniques (isoscapes) for spatiotemporally coherent isotope predictions. Cluster-based isoscape regionalization combines the advantages of local or regional prediction calibrations into a global framework. Here we present a revision of a Regionalized Cluster-Based Water Isotope Prediction model (RCWIP2) incorporating new isotope data having extensive spatial coverage and a wider array of predictor variables combined with high-resolution gridded climatic data. We introduced coupling of δ¹⁸O and δ²H (e.g., d-excess constrained) in the model predictions to prevent runaway isoscapes when each isotope is modelled separately and cross-checked observed versus modelled d-excess values. We improved model error quantification by adopting full uncertainty propagation in all calculations. RCWIP2 improved the RMSE over previous isoscape models by ca. 0.3 ‰ for δ¹⁸O and 2.5 ‰ for δ²H with an uncertainty <1.0 ‰ for δ¹⁸O and < 8 ‰ for δ²H for most regions of the world. The determination of the relative importance of each predictor variable in each ecoclimatic zone is a new approach to identify previously unrecognized climatic drivers on mean annual precipitation δ¹⁸O and δ²H. The improved RCWIP2 isoscape grids and maps (season, monthly, annual, regional) are available for download at https://isotopehydrologynetwork.iaea.org .  相似文献   

A bio-available strontium isoscape for eastern Beringia: a tool for tracking landscape use of Pleistocene megafauna     

Juliette Funck  Clement Bataille  Jeffrey Rasic  Matthew Wooller 《第四纪科学杂志》2021,36(1):76-90

Numerous paleoecological questions concern the mobility of ancient fauna in eastern Beringia. Strontium (Sr) isotope ratio (⁸⁷Sr/⁸⁶Sr) analysis has emerged as a powerful tracer for determining the provenance of ancient biological materials. However, it is important to characterize ⁸⁷Sr/⁸⁶Sr variation across a landscape. We measured the ⁸⁷Sr/⁸⁶Sr composition of teeth from present-day, herbivorous rodents (n = 162) sampled from across eastern Beringia to estimate bio-available ⁸⁷Sr/⁸⁶Sr values. We compiled these data with the very limited number of previously published ⁸⁷Sr/⁸⁶Sr values from the region. We then used this dataset and a machine learning, random-forest regression to predict bio-available ⁸⁷Sr/⁸⁶Sr variations across eastern Beringia. As a case study using our new ⁸⁷Sr/⁸⁶Sr map (isoscape), we measured the ⁸⁷Sr/⁸⁶Sr and oxygen stable isotope values (δ¹⁸O) of five radiocarbon-dated steppe bison from eastern Beringia and compared these to our ⁸⁷Sr/⁸⁶Sr isoscape and a δ¹⁸O isoscape to estimate the probable landscape use of these ancient fauna. Our model and isoscape provide important foundations for a wide range of additional applications, including studies of the paleo-mobility of other fauna, ancient people and present-day fauna in eastern Beringia.  相似文献   

A comparison of snowmelt‐derived streamflow from temperature‐index and modified‐temperature‐index snow models     

Michael L. Follum  Jeffrey D. Niemann  Steven R. Fassnacht 《水文研究》2019,33(23):3030-3045

Reliable estimation of the volume and timing of snowmelt runoff is vital for water supply and flood forecasting in snow‐dominated regions. Snowmelt is often simulated using temperature‐index (TI) models due to their applicability in data‐sparse environments. Previous research has shown that a modified‐TI model, which uses a radiation‐derived proxy temperature instead of air temperature as its surrogate for available energy, can produce more accurate snow‐covered area (SCA) maps than a traditional TI model. However, it is unclear whether the improved SCA maps are associated with improved snow water equivalent (SWE) estimation across the watershed or improved snowmelt‐derived streamflow simulation. This paper evaluates whether a modified‐TI model produces better streamflow estimates than a TI model when they are used within a fully distributed hydrologic model. It further evaluates the performance of the two models when they are calibrated using either point SWE measurements or SCA maps. The Senator Beck Basin in Colorado is used as the study site because its surface is largely bedrock, which reduces the role of infiltration and emphasizes the role of the SWE pattern on streamflow generation. Streamflow is simulated using both models for 6 years. The modified‐TI model produces more accurate streamflow estimates (including flow volume and peak flow rate) than the TI model, likely because the modified‐TI model better reproduces the SWE pattern across the watershed. Both models also produce better performance when calibrated with SCA maps instead of point SWE data, likely because the SCA maps better constrain the space‐time pattern of SWE.  相似文献   

Impact of heat advection on the thermal regime of roads built on permafrost     

Lin Chen  Daniel Fortier  Jeffrey M. McKenzie  Michel Sliger 《水文研究》2020,34(7):1647-1664

In northern regions, transportation infrastructure can experience severe structural damages due to permafrost degradation. Water infiltration and subsurface water flow under an embankment affect the energy balance of roadways and underlying permafrost. However, the quantification of the processes controlling these changes and a detailed investigation of their thermal impacts remain largely unknown due to a lack of available long-term embankment temperature data in permafrost regions. Here, we report observations of heat advection linked to surface water infiltration and subsurface flow based on a 9-year (from 2009 to 2017) thermal monitoring at an experimental road test site built on ice-rich permafrost conditions in southwestern Yukon, Canada. Our results show that snowmelt water infiltration in the spring rapidly increases temperature in the upper portion of the embankment. The earlier disappearance of snow deposited at the embankment slope increases the thawing period and the temperature gradient in the embankment compared with the natural ground. Infiltrated summer rainfall water lowered the near-surface temperatures and subsequently warmed embankment fill materials down to 3.6-m depth. Heat advection caused by the flow of subsurface water produced warming rates at depth in the embankment subgrade up to two orders of magnitude faster than by atmospheric warming (heat conduction). Subsurface water flow promoted permafrost thawing under the road embankment and led to an increase in active layer thickness. We conclude that the thermal stability of roadways along the Alaska Highway corridor is not maintainable in situations where water is flowing under the infrastructure unless mitigation techniques are used. Severe structural damages to the highway embankment are expected to occur in the next decade.  相似文献