Evaluation of a low‐cost temperature measurement system for environmental applications     

Jason Hubbart  Timothy Link  Colin Campbell  Doug Cobos 《水文研究》2005,19(7):1517-1523

Thermochron iButtons incorporate the latest in digital technology, making them smaller, less expensive, durable and potentially more reliable than many other temperature logging devices. The objective of this study was to test the accuracy of an inexpensive air temperature measurement system, composed of a Thermochron iButton and radiation shield. Sixty‐one iButtons were subjected to a sequence of two water baths (0 °C and 24·9 °C) to assess the absolute accuracy of the sensors. Five solar radiation shields were tested in a greenhouse setting to evaluate the reduction in radiative heating. Significant differences (p < 0·05) were detected between instruments subsequent to both water‐bath treatment analyses. The accuracy of the sensors was well within the manufacturer's stated specification of ±1·0 °C with a collective temperature variance of ±0·21 °C. Temperature responses generated by the Thermochron iButtons in different radiation shields were consistent, but varied significantly (p < 0·05) from 28 to 44 °C based on diurnal temperature ranges. Results indicate that the Thermochron iButton is an accurate, inexpensive alternative to more expensive temperature data‐logging systems, and is well suited for obtaining quality spatially distributed data for hydrologic and water quality investigations. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Pleistocene Rhine–Thames landscapes: geological background for hominin occupation of the southern North Sea region     

Marc P. Hijma  Kim M. Cohen  Wil Roebroeks  Wim E. Westerhoff  Freek S. Busschers 《第四纪科学杂志》2012,27(1):17-39

This paper links research questions in Quaternary geology with those in Palaeolithic archaeology. A detailed geological reconstruction of The Netherlands' south‐west offshore area provides a stratigraphical context for archaeological and palaeontological finds. Progressive environmental developments have left a strong imprint on the area's Palaeolithic record. We highlight aspects of landscape evolution and related taphonomical changes, visualized in maps for critical periods of the Pleistocene in the wider southern North Sea region. The Middle Pleistocene record is divided into two palaeogeographical stages: the pre‐Anglian/Elsterian stage, during which a wide land bridge existed between England and Belgium even during marine highstands; and the Anglian/Elsterian to Saalian interglacial, with a narrower land bridge, lowered by proglacial erosion but not yet fully eroded. The Late Pleistocene landscape was very different, with the land bridge fully dissected by an axial Rhine–Thames valley, eroded deep enough to fully connect the English Channel and the North Sea during periods of highstand. This tripartite staging implies great differences in (i) possible migration routes of herds of herbivores as well as hominins preying upon them, (ii) the erosion base of axial and tributary rivers causing an increase in the availability of flint raw materials and (iii) conditions for loess accumulation in northern France and Belgium and the resulting preservation of Middle Palaeolithic sites. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Synoptic climatology of nuisance flooding along the Atlantic and Gulf of Mexico coasts,USA     

Vega  Anthony J.  Miller  Paul W.  Rohli  Robert V.  Heavilin  Jason 《Natural Hazards》2021,105(2):1281-1297

Natural Hazards - Nuisance flooding (NF; also known as high-tide, or “sunny day” flooding) is an increasingly prevalent phenomenon afflicting coastal developments worldwide. NF often...  相似文献   

Analysis of loess landslide mechanism and numerical simulation stabilization on the Loess Plateau in Central China     

Xie  Wan-li  Guo  Qianyi  Wu  Jason Y.  Li  Ping  Yang  Hui  Zhang  Maosheng 《Natural Hazards》2021,106(1):805-827

Natural Hazards - Loess landslides have complicated deformation mechanisms. Accurately describing the internal failure deformation of loess landslides and establishing a theoretical method of...  相似文献   

Integrating international linguistic minorities in emergency planning at institutions of higher education     

Abukhalaf  Amer Hamad Issa  von Meding  Jason 《Natural Hazards》2021,109(1):845-869

Natural Hazards - Research concerning the behavior of international linguistic minorities at institutions of higher education during disasters is very limited. Many international groups suffer from...  相似文献   

Experimental constraints on the mobility of Rhenium in silicate liquids     

Jason M. MacKenzie  Dante Canil 《Geochimica et cosmochimica acta》2006,70(20):5236-5245

The volatization of Rhenium (Re) from melts of natural basalt, dacite and a synthetic composition in the CaO-MgO-Al₂O₃-SiO₂ system has been investigated at 0.1 MPa and 1250-1350 °C over a range of fO₂ conditions from log fO₂ = −10 to −0.68. Experiments were conducted using open top Pt crucibles doped with Re and Yb. Analysis of quenched glasses by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) normal to the melt/gas interface showed concentration profiles for Re, to which a semi-infinite one-dimensional diffusion model could be applied to extract diffusion coefficients (D). The results show Re diffusivity in basalt at 1300 °C in air is log D_Re = −7.2 ± 0.3 cm²/s and increases to log D_Re = −6.6 ± 0.3 cm²/s when trace amounts of Cl were added to the starting material. At fO₂ conditions below the nickel-nickel oxide (NNO) buffer Re diffusivity decreases to and to in dacitic melt. In the CMAS composition, . The diffusivity of Re is comparable to Ar and CO₂ in basalt at 500 MPa favoring its release as a volatile. Our results support the contention that subaerial degassing is the cause of lower Re concentrations in arc-type and ocean island basalts compared to mid-ocean ridge basalts.  相似文献   

Estimating long-term soil respiration rates from carbon isotopes occluded in gibbsite     

Paul A. Schroeder  Jason C. Austin  John F. Dowd 《Geochimica et cosmochimica acta》2006,70(23):5692-5697

Carbon occluded in the soil gibbsite crystal structure at the Panola Mountain Research Watershed, Georgia, U.S. is presumed to be in isotopic equilibrium with the CO₂ respired from soil organics by microbes and plant roots. Fitting of the stable carbon isotopic data to a Fickian diffusion-based depth function results in an estimate of 47 gC m⁻² y⁻¹ for the long-term soil respiration rate. A numerical model that includes depth-dependent production and diffusion terms results in estimates of 28-12 gC m⁻² y⁻¹. These values range from 15 to 50 times less than the average of modern values for mixed deciduous forests in wet temperate climates. This disparity has several implications for our understanding of the geologic record of climate change, which include: (1) evidence for a cooler and seasonally drier climate during the mid-Holocene in the southeastern U.S., or (2) fluxes of carbon from the soil pool as recorded by soil mineral proxies (i.e., long-term soil respiration rates) under estimate atmosphere annual carbon flux measurements (i.e., short-term measures), and (3) the need to refine soil respiration models used to relate paleosol stable carbon isotopic measurements to paleo-atmospheric estimates.  相似文献   

A multi-proxy lacustrine record of Holocene climate change on northeastern Baffin Island, Arctic Canada   总被引：3，自引：0，他引：3  

Jason P. Briner  Neal Michelutti  Donna R. Francis  Gifford H. Miller  Yarrow Axford  Matthew J. Wooller  Alexander P. Wolfe 《Quaternary Research》2006,65(3):431-442

Reconstructions of past environmental changes are critical for understanding the natural variability of Earth's climate system and for providing a context for present and future global change. Radiocarbon-dated lake sediments from Lake CF3, northeastern Baffin Island, Arctic Canada, are used to reconstruct past environmental conditions over the last 11,200 years. Numerous proxies, including chironomid-inferred July air temperatures, diatom-inferred lakewater pH, and sediment organic matter, reveal a pronounced Holocene thermal maximum as much as 5°C warmer than historic summer temperatures from 10,000 to 8500 cal yr B.P. Following rapid cooling 8500 cal yr B.P., Lake CF3 proxies indicate cooling through the late Holocene. At many sites in northeastern Canada, the Holocene thermal maximum occurred later than at Lake CF3; this late onset of Holocene warmth is generally attributed to the impacts of the decaying Laurentide Ice Sheet on early Holocene temperatures in northeastern Canada. However, the lacustrine proxies in Lake CF3 apparently responded to insolation-driven warmth, despite the proximity of Lake CF3 to the Laurentide Ice Sheet and its meltwater. The magnitude and timing of the Holocene thermal maximum at Lake CF3 indicate that temperatures and environmental conditions at this site are highly sensitive to changes in radiative forcing.  相似文献   

A comparison of permafrost prediction models along a section of Trail Ridge Road, Rocky Mountain National Park, Colorado, USA   总被引：1，自引：0，他引：1  

Jason R. Janke  Mark W. Williams 《Geomorphology》2012,138(1):111-120

The distribution of mountain permafrost along Trail Ridge Road (TRR) in Rocky Mountain National Park, Colorado, was modeled using ‘frost numbers’ and a ‘temperature of permafrost model’ (TTOP) in order to assess the accuracy of prediction models. The TTOP model is based on regional observations of air temperature and heat transfer functions involving vegetation, soil, and snow; whereas the frost number model is based on site-specific ratios of ground temperature measurements of frozen and thawed degree-days. Thirty HOBO© temperature data loggers were installed near the surface as well as at depth (30 to 85 cm). From mid-July 2008 to 2010, the mean annual soil temperature (MAST) for all surface sites was − 1.5 °C. Frost numbers averaged 0.56; TTOP averaged − 1.8 °C. The MAST was colder on western-facing slopes at high elevations. Surface and deeper probes had similar MASTs; however, deeper probes had less daily and seasonal variation. Another model developed at the regional scale based on proxy indicators of permafrost (rock glaciers and land cover) classified 5.1 km² of permafrost within the study area, whereas co-kriging interpolations of frost numbers and TTOP data indicated 2.0 km² and 4.6 km² of permafrost, respectively. Only 0.8 km² were common among all three models. Three boreholes drilled within 2 m of TRR indicate that permafrost does not exist at these locations despite each borehole being classified as containing permafrost by at least one model. Addressing model uncertainty is important because nutrients stored within frozen or frost-affected soils can be released and impact alpine water bodies. The uncertainty also exposes two fundamental problems: empirical models designed for high latitudes are not necessarily applicable to mountain permafrost, and the presence of mountain permafrost in the alpine tundra of the Colorado Front Range has not been validated.  相似文献   

The level and nature of sustainability for clusters of abandoned limestone quarries in the southern Palestinian West Bank     

Jason Phillips 《Applied geography (Sevenoaks, England)》2012,32(2):376-392

The question of how sustainable a mining site is at the end of its operational life has been somewhat unanswered. The fundamental problem has been how to evaluate the sustainability of a mining site once operations cease and is abandoned. Environmental Impact Assessment (EIA) is certainly a way to evaluate sustainability of such sites, but only through inference and subjective evaluation. This is because the topic of sustainability still hotly debated, and is predominantly focussed on an anthropocentric approach. Even with quantitative-based EIAs, the question is how to directly evaluate sustainability from the data available using a consistent quantitative approach rather than on a case-by-case basis or subjective evaluation.However, by using the ideas and concepts concerning the coupled relationship between the environment and humans prevalent in sustainability science, the question of what is and how to evaluate sustainability has become capable of being answered. Based on previous work of the author in the development and application of a mathematical model of sustainability, the paper applies the model to the results of a quantitative EIA evaluation for nine clusters of abandoned limestone quarries located in the southern Palestinian West Bank.The results indicate that seven of the nine clusters were deemed to be unsustainable, whilst the other two clusters were considered as sustainable at a very weak level only. The results are discussed within the broader context of the coupled environment-human system using one of the supporting frameworks for the development and application of the mathematical model of sustainability: Earth System Analysis. Within this context, the discussion indicates the fact that unmanaged impacts by humans has created the situation for unsustainability to occur. The paper therefore provides for the clearest indication yet of the nature of sustainability at the end of the mining operational life-cycle without an effective and proper management strategy or policies.  相似文献