Consistent scale-dependency of future increases in hourly extreme precipitation in two convection-permitting climate models     

Helsen  Samuel  van Lipzig  Nicole P. M.  Demuzere  Matthias  Vanden Broucke  Sam  Caluwaerts  Steven  De Cruz  Lesley  De Troch  Rozemien  Hamdi  Rafiq  Termonia  Piet  Van Schaeybroeck  Bert  Wouters  Hendrik 《Climate Dynamics》2020,54(3):1267-1280

Climate Dynamics - Convection-permitting models (CPMs) have been proven successful in simulating extreme precipitation statistics. However, when such models are used to study climate change,...  相似文献   

Assembling Birrarung Wilam: a case study of Indigenous public artwork in the city     

Julia Flaster  Lesley Head 《The Australian geographer》2020,51(1):19-34

ABSTRACT

Indigenous public artworks in Australian urban spaces have challenged assumptions of Indigenous absence from the city. This paper examines the construction of Birrarung Wilam, in central Melbourne, in the period 2005–2008. We use archival documents and semi-structured interviews to analyse the collaborations between Indigenous and non-Indigenous participants in a project sponsored by the city. We show the particular mediating contribution of ‘fabricators’: a group of commissioned workers and tradespeople with material-specific expertise. Person to person encounters occurred through the modules of project management, with limited scope for long-term engagement. Despite being embedded in formal state-based recognition, Birrarung Wilam asserts Indigenous self-recognition through the renewal and adaptation of Indigenous material practices and traditions and the refusal to provide straightforward interpretive materials at the site. The study provides support for arguments that challenge a simple binary of co-option and resistance in interpreting such public art practice.  相似文献   

A special issue dedicated to microbial geochemistry     

Lesley A Warren 《Geochimica et cosmochimica acta》2004,68(15):3139

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Overview of the special issue: a multi-model framework to achieve consistent evaluation of climate change impacts in the United States     

Stephanie T. Waldhoff  Jeremy Martinich  Marcus Sarofim  Benjamin DeAngelo  Jim McFarland  Lesley Jantarasami  Kate Shouse  Allison Crimmins  Sara Ohrel  Jia Li 《Climatic change》2015,131(1):1-20

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An event-based approach to understanding decadal fluctuations in the Atlantic meridional overturning circulation     

Lesley Allison  Ed Hawkins  Tim Woollings 《Climate Dynamics》2015,44(1-2):163-190

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Chandra observation of NGC 4449: analysis of the X-ray emission from a dwarf starburst galaxy   总被引：1，自引：0，他引：1  

Lesley K. Summers  Ian R. Stevens  David K. Strickland †  Timothy M. Heckman 《Monthly notices of the Royal Astronomical Society》2003,342(3):690-708

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The influence of the ocean on the chemistry of precipitation in Nova Scotia*     

J.K. Underwood  D.H. Waller  D. Thirumurthi 《大气与海洋》2013,51(3):467-479

Abstract

Between the fall of 1977 and December 1980, over 800 samples of precipitation were collected at 9 rural locations across Nova Scotia.

Average pH was 4.61, and an average conductivity of 25 μS cm^?1 confirmed the low ionic strength of rain and snow. Of all ions, chloride was the most abundant at 76 μeq L^?1 (2.7 mg L^?1). Oceanic origins were perceived as the source for chloride as well as for Na, Mg, 51 % of K, 21% of Ca, and 21% of SO₄, and the sea collectively accounted for 66% of all ions inNova Scotian precipitation. In contrast, the dominating ions in New York, New Hampshire, Ontario and Norway were H⁺ and SO₄.

In Nova Scotia, chloride concentrations in rain (mg L^?1) are a function of distance D (km) from the coast and may be described by the equation Cl [mg L^?1] = 4.5D^?0.42. It indicates that Cl concentrations are reduced by about 50% within 0.5 km of the coast, and 80% within 5 km. The continental North American chloride data examined are also consistent with the relationship.

The shape of the chloride curve is similar to curves others have developed from rain and lake water chemistry observations in Holland and the United Kingdom, although those, and other European data, indicate that the marine influence is less pronounced in northeastern North America.

The marine influence of precipitation chemistry on Nova Scotia has a maximum seasonal amplitude during the winter.  相似文献   

Offshore Atlas Project: Methodology and Results     

Lesley D. Nixon  Barbara J. Bascle  David A. Marin 《Marine Georesources & Geotechnology》2013,31(2-3):211-212

The Offshore Atlas Project (OAP) grouped 4,325 Miocene and older and 5,622 Pliocene and Pleistocene productive sands in the Gulf of Mexico into 91 chronostratigraphic hydrocarbon plays to aid the oil and gas industry with regional hydrocarbon exploration and field development. OAP has produced a two-volume atlas series entitled Atlas of Northern Gulf of Mexico Gas and Oil Reservoirs. Volume 1 comprises Miocene and older reservoirs, while volume 2 comprises Pliocene and Pleistocene reservoirs. Chronozones (Reed et al., 1987) were used to define geologic ages in the Gulf of Mexico. A chronozone is a time-stratigraphic unit defined by a particular benthic foraminifera biostratigraphic zone. The 26 chronozones identified by Reed et al. (1987) were further grouped into 14 Cenozoic and 2 Mesozoic chronozones for OAP. A composite type log (CTL), which shows the chronostratigraphic relationship of all productive sands in a field, was constructed for each of the 876 proved federal fields in the Gulf of Mexico. Depositional facies (retrogradational, aggradational, progradational, and submarine fan)were next identified on each CTL. The four facies were identified primarily according to characteristic SP-curve shapes, paleoecozones, and sand content. The chronozones and depositional facies identified on each CTL were then correlated among fields across the Gulf of Mexico. All productive sands correlated to the same chronozone and depositional facies were then identified as a unique play. Both federal and state fields in the Gulf of Mexico contain original proved reserves (sum of cumulative production and remaining proved reserves) estimated at 12.481 Bbbl of oil and condensate and 156.466 Tcf of gas (40.322 Bboe [sum of liquids and energy equivalent gas]). Of this, 9.943 Bbbl of oil and condensate and 122.263 Tcf of gas (31.698 Bboe) have been produced. Miocene plays contain the most total original proved reserves with 41.9 %, followed by Pleistocene plays (36.2 %), Pliocene plays (18.6 %), Mesozoic plays (2.9 %), and Oligocene plays (0.4 %). Miocene plays have produced the largest amount of total hydrocarbons, as well, at 43.5 % followed by Pleistocene plays (36.5 %), Pliocene plays (19.1 %), Oligocene plays (0.5 %), and Mesozoic plays (0.4 %). Just over two-thirds of the Gulf of Mexico's total original proved reserves are contained in progradational facies (67.4 %),with the remainder comprising submarine-fan facies (18.5 %), aggradational facies (9.9 %), retrogradationalfacies (2.4 %), combination facies (1.7 %), and caprock and reef reservoirs (0.1 %). Total cumulative production from the different facies closely mimics the distribution of original proved reserves. Of the 91 plays, the lower Pleistocene progradational play (LPL P.1) contains the most original proved gas reserves (10.5 %) and has produced the most gas (11.4 %). However, the upper upper Miocene eastern progradational play (UM3 P.1B) contains the most original proved oil and condensate reserves (18.9 %) and has produced the most oil and condensate (21.4%). Several technical studies resulting from OAP have been published. Hunt and Burgess (1995) described the distribution of OAP plays deposited by the ancestral Mississippi River delta system in the north-central Gulf of Mexico over the past 24 million years. The lower Miocene plays are restricted to the westernmost portion of the Louisiana shelf. In the late middle Miocene, the depocenter migrated east of the present-day Mississippi River delta. During the late upper Miocene, the depocenter began migrating back to the west and prograded basinward, and it continued to do so throughout the Pliocene and Pleistocene. Lore and Batchelder (1995) discussed how OAP plays can be used to find exploration targets and assess undiscovered resources. As an exploration tool, OAP play maps can be used to identify conceptual submarine-fan plays downdip of established shallow water producing facies, and to identify wells where a known producing facies or chronozone has not yet been reached. As an assessment tool, the extensive data sets associated with each OAP play can be used to infer statistically the size of undiscovered resources in a play to determine if exploration in that play is economically justifiable. Lore et al. (1995) estimated the amount of undiscovered conventionally recoverable resources in the Gulf of Mexico, basing their assessment on previous work performed for OAP. Mean level estimates show that, by far, submarine-fan plays have the greatest potential for additional oil and gas in the Gulf of Mexico, with 75.1 % and 70.4 % of the total oil and gas resources, respectively. Mean level estimates for the 13 OAP Miocene, Pliocene, and Pleistocene chronozones show that upper Pleistocene plays have the most oil resource potential (24.3 %), while lower Pleistocene plays have the most gas resource potential (20.6 %).  相似文献   

Metabolic patterning of biosilicification     

Derek R. Amores  Lesley A. Warren   《Chemical Geology》2009,268(1-2):81-88

Here we show a discernibly unique biosilicification pattern for live, metabolically active Synechococcus cyanobacterial cell surfaces compared to dead Synechococcus cells under identical experimental conditions. The live cell treatments showed signs of cell division and the growth of fimbriae indicating metabolic activity during the 5-day silicification experiment. Live treatment cells were also recultivable after the experiments confirming their continued viability. The metabolically active live cyanobacteria treatment bound twice the amount of colloidal SiO₂ and held it more tightly compared to the dead cell treatment. Further, biosilicification of the live, actively metabolizing bacteria was unipolar, leaving the core surface largely unencrusted. In contrast, biosilicification of the dead cells was heterogeneous, occurring across the entire cell surface with no observable localized pattern. The directed biosilicification localization of live cell surfaces is likely a bacterial strategy to protect the cell functionality against the potentially inhibitory effects of mineral encrustation. Localization of silica biominerals to the polar end of the cell is also consistent with reported bacteria regulated cell polarity, which, under the experimental pH of 3, would enable localized differential attraction between the charged colloidal silica (+) particles and the bacterial cell polar surface (−). Our results show a novel metabolically-linked distinct colloidal SiO₂ biomineralization fingerprint, suggesting a putative biomineralization signature.  相似文献   

The three dimensional structure of the atmospheric energy budget: methodology and evaluation   总被引：1，自引：0，他引：1  

Kevin E. Trenberth  Lesley Smith 《Climate Dynamics》2009,32(7-8):1065-1079

Studies of the vertically-integrated energy and moisture budgets of the atmosphere are expanded to three dimensions. The vertical integrals of the moisture, energy and heat budget equations computed analytically act as a very strong constraint on any local computational results of the vertical structure. This paper focuses on the methodology and difficulties in closing the budgets and satisfying constraints, given the need to use a pressure coordinate because model coordinates all differ. Vertical interpolation destroys delicate mass balances and can lead to inconsistencies, such as from how geopotential or vertical motion is computed. Using the advective rather than flux form of the equations greatly reduces the contamination from these effects. Results are documented for January 1989 using European Centre for Medium Range Weather Forecasts reanalysis (ERA-40) data. The moistening, diabatic heating and total energy forcing of the atmosphere are computed as a residual from the analyses using the moisture, dry energy (dry static energy plus kinetic energy) and total atmospheric (moist static plus kinetic) energy equations. The components from the monthly averaged flow and transients, as a function of layer in the atmosphere, and as quasi-horizontal and vertical fluxes of dry static, latent and kinetic energy are examined. Results show the moistening of the atmosphere at the surface, its release as latent heat in precipitation and transformation into dry static energy, and thus net radiative cooling as a function of height and location. The vertically integrated forcings computed from the model parameterizations are compared with available observations and budget-derived values, and large ERA-40 model biases are revealed in radiation and precipitation. The energy and moisture budget-derived quantities are more realistic, although results depend on the quality of the analyses which are not constructed to conserve mass, moisture or energy, owing to analysis increments.  相似文献