Estimating impacts of warming temperatures on California's electricity system     

Jayant A. Sathaye  Larry L. Dale  Peter H. Larsen  Gary A. Fitts  Kevin Koy  Sarah M. Lewis  André Frossard Pereira de Lucena 《Global Environmental Change》2013,23(2):499-511

Despite a clear need, little research has been carried out at the regional-level to quantify potential climate-related impacts to electricity production and delivery systems. This paper introduces a bottom-up study of climate change impacts on California's energy infrastructure, including high temperature effects on power plant capacity, transmission lines, substation capacity, and peak electricity demand. End-of-century impacts were projected using the A2 and B1 Intergovernmental Panel on Climate Change emission scenarios. The study quantifies the effect of high ambient temperatures on electricity generation, the capacity of substations and transmission lines, and the demand for peak power for a set of climate scenarios. Based on these scenarios, atmospheric warming and associated peak demand increases would necessitate up to 38% of additional peak generation capacity and up to 31% additional transmission capacity, assuming current infrastructure. These findings, although based on a limited number of scenarios, suggest that additional funding could be put to good use by supporting R&D into next generation cooling equipment technologies, diversifying the power generation mix without compromising the system's operational flexibility, and designing effective demand side management programs.  相似文献   

Nitrogen and sulfur species in Antarctic aerosols at Mawson,Palmer Station,and Marsh (King George Island)   总被引：4，自引：0，他引：4  

D. L. Savoie  J. M. Prospero  R. J. Larsen  F. Huang  M. A. Izaguirre  T. Huang  T. H. Snowdon  L. Custals  C. G. Sanderson 《Journal of Atmospheric Chemistry》1993,17(2):95-122

High volume bulk aerosol samples were collected continuously at three Antarctic sites: Mawson (67.60° S, 62.50° E) from 20 February 1987 to 6 January 1992; Palmer Station (64.77° S, 64.06° W) from 3 April 1990 to 15 June 1991; and Marsh (62.18° S, 58.30° W) from 28 March 1990, to 1 May 1991. All samples were analyzed for Na⁺, SO ₄ ^2– , NO ₃ ^– , methanesulfonate (MSA), NH ₄ ⁺ ,²¹⁰Pb, and⁷Be. At Mawson for which we have a multiple year data set, the annual mean concentration of each species sometimes vary significantly from one year to the next: Na⁺, 68–151 ng m^–3; NO ₃ ^– , 25–30 ng m^–3; nss SO ₄ ^2– , 81–97 ng m^–3; MSA, 19–28 ng m^–3; NH ₄ ⁺ , 16–21 ng m^–3;²¹⁰Pb, 0.75–0.86 fCi m^–3. Results from multiple variable regression of non-sea-salt (nss) SO ₄ ^2– with MSA and NO ₃ ^– as the independent variables indicates that, at Mawson, the nss SO ₄ ^2– /MSA ratio resulting from the oxidation of dimethylsulfide (DMS) is 2.80±0.13, about 13% lower than our earlier estimate (3.22) that was based on 2.5 years of data. A similar analysis indicates that the ratio at Palmer is about 40% lower, 1.71±0.10, and more comparable to previous results over the southern oceans. These results when combined with previously published data suggest that the differences in the ratio may reflect a more rapid loss of MSA relative to nss SO ₄ ^2– during transport over Antarctica from the oceanic source region. The mean²¹⁰Pb concentrations at Palmer and Marsh and the mean NO ₃ ^– concentration at Palmer are about a factor of two lower than those at Mawson. The²¹⁰Pb distributions are consistent with a²¹⁰Pb minimum in the marine boundary layer in the region of 40°–60° S. These features and the similar seasonalities of NO ₃ ^– and²¹⁰Pb at Mawson support the conclusion that the primary source regions for NO ₃ ^– are continental. In contrast, the mean concentrations of MSA, nss SO ₄ ^2– , and NH ₄ ⁺ at Palmer are all higher than those at Mawson: MSA by a factor of 2; nss SO ₄ ^2– by 10%; and NH ₄ ⁺ by more than 50%. However, the factor differences exhibit substantial seasonal variability; the largest differences generally occur during the austral summer when the concentrations of most of the species are highest. NH ₄ ⁺ /(nss SO ₄ ^2– +MSA) equivalent ratios indicate that NH₃ neutralizes about 60% of the sulfur acids during December at both Mawson and Palmer, but only about 30% at Mawson during February and March.  相似文献   

Tungsten skarn mineralizations in a regional metamorphic terrain in northern Norway: a possible metamorphic ore deposit   总被引：2，自引：0，他引：2  

R. Berg Larsen 《Mineralium Deposita》1991,26(4):281-289

Scheelite- and molybdenite-bearing scapolite skarn and plagioclase skarn occur as stratabound mineralizations in a terrain which has suffered regional metamorphism. Scapolite skarn formed as replacement skarns in plagioclase-bearing hornblendic gneiss whereas plagioclase skarn precipitated in fractures as vein skarn mineralizations. The genesis of these skarn deposits are closely connected to an episode of boudinage on the limbs of a large-scale dome-shaped fold. Fluid inclusion studies revealed that the ore-forming fluids were composed of CO₂ with 2 to 17 mole% CH₄, which formed due to decarbonation reactions during peak metamorphism at the end of the Caledonian orogenesis. Thermodynamic considerations indicate that scapolite and plagioclase formed above 550 °C and 2 Kbar pressure and were followed by precipitation of scheelite between 400 and 570 °C.  相似文献   

Slab weakening: Mechanical and thermal-mechanical consequences for slab detachment     

Shoichi  Yoshioka David A.  Yuen Tine B.  Larsen 《Island Arc》1995,4(2):89-103

Abstract Slab detachment is a geophysical instability whose manifestation can be revealed by seismic tomography. Evidence of this phenomenon is in the Dinarides/Hellenic and the New Hebrides subduction zones. Subducted slabs in these regions are torn horizontally at depths ranging from 100 to 300 km. We constructed a viscoelastic three-dimensional finite element model and investigated the state of stress. We found that an area with high stress concentration of the order of several hundred MPa is formed near the tip of the tear inside the slab, which can cause lateral migration of the tear. Favorable conditions for slab detachment are characterized by large interplate frictional force at a subduction zone and small slab resistance force deeper down. Stress concentration increases with the down-dip tension inside the slab. The phenomenon of slab weakening has also been studied from a thermal-mechanical standpoint, using a two-dimensional convection model with non-Newtonian, temperature-dependent rheology. The stress-dependent rheology plays an important role in causing local weakening of the descending slab. In strongly time-dependent situations the fast descending slab is not strong everywhere but has a weak region in the middle, making it vulnerable to slab detachment. The presence of viscous heating will enhance slab detachment tendency by further weakening the interior by the frictional heating. Besides these effects, there are other mechanisms which can also weaken the slab interior and help to make slabs more pliable and susceptible to detachment.  相似文献   

The age of carbonatites,kimberlites and lamprophyres from southern West Greenland: recurrent alkaline magmatism during 2500 million years     

Lotte Melchior Larsen  David C. Rex  Karsten Secher 《Lithos》1983,16(3):215-221

Alkaline rocks were intruded into the Precambrian basement in southern West Greenland during at least five separate episodes. The Tupertalik carbonatite intrusion was emplaced around or before 2650 m.y.; it is now metamorphosed in granulite facies but is recognisable by its trace element content. Lamprophyre dykes were intruded at ca. 1800 m.y. and again at ca. 1200 m.y. At ca. 600 m.y. the Sarfartôq carbonatite intrusion and extensive kimberlite dykes were emplaced in the Holsteiborg-Strømfjord region. At 225-115 m.y. the Qaqarssuk carbonatite complex was emplaced in the Sukkertoppen region, and numerous lamprophyre and kimberlite dykes were emplaced between Fishenasset and Ivigtut. All these episodes are correlatable with contemporaneous alkaline activity in Canada and Scandinavia and substantiate the periodicity of carbonatite emplacement. The Mesozoic suite of intrusions is related to rifting prior to continental break-up and the formation of the North Atlantic Ocean. The Eocambrian suite of 600 m.y. is thought to have formed under similar conditions during continental break-up and the formation of the Iapetus ocean.  相似文献   

Influence of Temporal Variations in River Discharge, pH, Alkalinity and Ca on the Speciation and Concentration of Heavy Metals in Some Mining Polluted Rivers     

Pål Gundersen  Eiliv Steinnes 《Aquatic Geochemistry》2001,7(3):173-193

Dissolved (dialysis in situ) and total concentrations ofCu, Zn, Cd and Al in eight mining polluted rivers in the Røros area, central Norway, were determinedby atomic absorption spectrometry (flame and graphite furnace) and compared to pH, Caconcentration and alkalinity through seasonal variations in river discharge. Totalconcentrations of the metals were highest during early spring flood and during summer andautumn rain episodes. Dissolved concentrations also increased as the spring floodproceeded, but small discharge peaks within this 2 month period as well as a considerableautumn flood episode appeared to lower rather than to raise the dissolved metal concentrations.Consequently the dissolved fractions of Zn, Cd and Al showed a significant negative correlationwith river discharge, and were low at the discharge peaks. Possibly high sediment concentrationsoccurring at high flood conditions more than counteracted desorption induced by pHdecrease, and led to decreased dissolved fractions through adsorption. Cu speciationon the other hand seemed to be more closely linked to pH. Alkalinity and Ca concentration,both assumed to protect aquatic life from metal pollution, were significantly lowerduring episodes with high Cu and Al total concentrations.  相似文献   

The salt decay of medieval bricks at a vault in Brarup Church,Denmark     

Poul Klenz Larsen 《Environmental Geology》2007,52(2):375-383

This paper presents an investigation of the decay of bricks in the chancel vault of Brarup Church located close to the Baltic Sea at the island of Falster in Denmark. The aim of the work was to study a peculiar phenomenon in order to prescribe appropriate treatment. Although protected by a lime plaster, some bricks were pulverized up to 50 mm deep from the topside. The decay occurred in a random pattern over the structure, with undamaged bricks positioned next to deteriorated bricks. The brick structure was investigated by Mercury Intrusion Porosiometry. All bricks had a majority of pores in the range 1–10 μm, but the decayed bricks also had a fraction of pores with a diameter less than 100 nm. The difference may be due to a lower firing temperature, or it may be a consequence of the salt decay. Salt analysis proved that the deteriorated bricks were contaminated with sodium chloride, which could have degraded the brick structure. However, the powdering of the bricks may be caused by the precipitation of gypsum, which was found in the brick powder but not in the deteriorated brick itself. According to calculations with the computer program RUNSALT, the precipitation of gypsum is much influenced by the presence of sodium chloride. The gypsum precipitates due to changes in temperature between 0 and 30°C and variations in relative humidity between 75 and 95%. Seasonal climatic changes in the attic were measured to cover this interval. Perhaps sodium chloride acted as a catalyst that facilitated the accumulation and precipitation of gypsum at the topside of the bricks. A sacrificial plaster, which is the traditional treatment for salt contaminated structures, would not prevent such decay.  相似文献   

The retrieval of cloud microphysical properties using satellite measurements and an in situ database     

Christophe Poix  Guy Febvre  Anne Fouilloux  Howard Larsen  Jean-Francois Gayet 《Annales Geophysicae》1996,14(1):98-106

By combining AVHRR data from the NOAA satellites with information from a database of in situ measurements, large-scale maps can be generated of the microphysical parameters most immediately significant for the modelling of global circulation and climate. From the satellite data, the clouds can be classified into cumuliform, stratiform and cirrus classes and then into further sub-classes by cloud top temperature. At the same time a database of in situ measurements made by research aircraft is classified into the same sub-classes and a statistical analysis is used to derive relationships between the sub-classes and the cloud microphysical properties. These two analyses are then linked to give estimates of the microphysical properties of the satellite observed clouds. Examples are given of the application of this technique to derive maps of the probability of occurrence of precipitating clouds and of precipitating water content derived from a case study within the International Cirrus Experiment (ICE) held in 1989 over the North Sea.  相似文献   

Site Response in Las Vegas Valley, Nevada from NTS Explosions and Earthquake Data     

Arthur Rodgers  Hrvoje Tkalcic  David McCallen  Shawn Larsen  Catherine Snelson 《Pure and Applied Geophysics》2006,163(1):55-80

We report site response in Las Vegas Valley (LVV) from historical recordings of Nevada Test Site (NTS) nuclear explosions and earthquake recordings from permanent and temporary seismic stations. Our data set significantly improves the spatial coverage of LVV over previous studies, especially in the northern, deeper parts of the basin. Site response at stations in LVV was measured for frequencies in the range 0.2–5.0 Hz using Standard Spectral Ratios (SSR) and Horizontal-Vertical Spectral Ratios (HVR). For the SSR measurements we used a reference site (approximately NEHRP B ``rock' classification) located on Frenchman Mountain outside the basin. Site response at sedimentary sites is variable in LVV with average amplifications approaching a factor of 10 at some frequencies. We observed peaks in the site response curves at frequencies clustered near 0.6, 1.2 and 2.0 Hz, with some sites showing additional lower amplitude peaks at higher frequencies. The spatial pattern of site response is strongly correlated with the reported depth to basement for frequencies between 0.2 and 3.0 Hz, although the frequency of peak amplification does not show a similar correlation. For a few sites where we have geotechnical shear velocities, the amplification shows a correlation with the average upper 30-meter shear velocities, V₃₀. We performed two-dimensional finite difference simulations and reproduced the observed peak site amplifications at 0.6 and 1.2 Hz with a low velocity near-surface layer with shear velocities 600–750 m/s and a thickness of 100–200 m. These modeling results indicate that the amplitude and frequencies of site response peaks in LVV are strongly controlled by shallow velocity structure.  相似文献   

Evolution of metamorphic volatiles during exhumation of microdiamond-bearing granulites in the Western Gneiss Region, Norway   总被引：1，自引：0，他引：1  

Rune B. Larsen  Elizabeth A. Eide  Ernst A. J. Burke 《Contributions to Mineralogy and Petrology》1998,133(1-2):106-121

Fluid inclusions in garnet, kyanite and quartz from microdiamond-bearing granulites in the Western Gneiss Region, Norway, document a conspicuous fluid evolution as the rocks were exhumed following Caledonian high- and ultrahigh-pressure (HP–UHP) metamorphism. The most important of the various fluid mixtures and daughter minerals in these rocks are: (N₂ + CO₂ + magnesian calcite), (N₂ + CO₂ + CH₄ + graphite + magnesian calcite), (N₂ + CH₄), (N₂ + CH₄ + H₂O), (CO₂) and (H₂O + NaCl + CaCl₂ + nahcolite). Rutile also occurs in the N₂ + CO₂ inclusions as a product of titanium diffusion from the garnet host into the fluid inclusions. Volatiles composed of N₂ + CO₂ + magnesian calcite characterise the ambient metamorphic environment between HP–UHP (peak) and early retrograde metamorphism. During progressive decompression, the mole fraction of N₂ increased in the fluid mixtures; as amphibolite-facies conditions were reached, CH₄ and later, H₂O, appeared in the fluids, concomitant with the disappearance of CO₂ and magnesian calcite. Graphite is ubiquitous in the host lithologies and fluid inclusions. Thermodynamic modelling of the metamorphic volatiles in a graphite-buffered C-O-H system demonstrates that the observed metamorphic volatile evolution was attainable only if the f _O2 increased from c. −3.5 (±0.3) to −0.8 (±0.3) log units relative to the FMQ oxygen buffer. External introduction of oxidising aqueous solutions along a system of interconnected ductile shear zones adequately explains the dramatic increase in the f _O2. The oxidising fluids introduced during exhumation were likely derived from dehydration of oceanic crust and continental sediments previously subducted during an extended period of continental collision in conjunction with the Caledonian orogeny. Received: 15 December 1997 / Accepted: 25 May 1998  相似文献