Characterization of Asian Dust during ACE-Asia   总被引：4，自引：1，他引：3  

R. Arimoto  Y.J. Kim  Y.P. Kim  P.K. Quinn  T.S. Bates  T.L. Anderson  S. Gong  I. Uno  M. Chin  B.J. Huebert  A.D. Clarke  Y. Shinozuka  R.J. Weber  J.R. Anderson  S.A. Guazzotti  R.C. Sullivan  D.A. Sodeman  K.A. Prather  I.N. Sokolik 《Global and Planetary Change》2006,52(1-4):23

ACE-Asia was a multi-national collaboration organized to investigate and understand the chemistry, radiative properties, and climatic effects of mineral dust and other aerosol particles in the East Asia/Northwest Pacific region. Studies conducted at the Gosan and Zhenbeitai surface supersites show striking variations in aerosol concentrations and properties that were affected by the occurrence and origins of the Asian dust storms, air mass pathways, and mixing during the transport. Investigations conducted on the R/V Ronald H. Brown (RHB) showed that dust had a pervasive influence on the chemical composition, size distribution, and optical properties of the aerosol. Analyses using an aerosol time-of-flight mass spectrometer on the RHB showed that most of the coarse-particle nitrate and sulfate in post-frontal air was associated with dust, and more remarkably, that competitive or exclusionary processes evidently are involved in the uptake or production of these substances. Studies conducted onboard the NCAR C-130 aircraft showed that coarse-mode dust was less absorbing and less hygroscopic than pollution aerosol and that there was little correlation in light scattering and absorption by the sub- vs. super-micrometer aerosol. Below 2 km, dust was commonly mixed with pollutants, and this had a stronger influence on the optical properties of the submicrometer particles than the coarse-mode dust; at higher altitudes, the dust was less affected by pollution. Single particle analyses of C-130 samples showed that the mixing of black carbon (BC) with dust was common, but only certain types of BC particles were aggregated. Models were used in the planning, execution and interpretative phases of ACE-Asia; and summaries of modeling results are presented to illustrate the progress being made in identifying new dust sources; in depicting the time-varying, three-dimensional structure of dust plumes; and in quantifying the production, transport, and deposition of Asian dust.  相似文献   

Conceptualization in catchment modelling: simply learning?     

S. M. Dunn  J. Freer  M. Weiler  M. J. Kirkby  J. Seibert  P. F. Quinn  G. Lischeid  D. Tetzlaff  C. Soulsby 《水文研究》2008,22(13):2389-2393

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Data conflicts in fishery models: incorporating hydroacoustic data into the Prince William Sound Pacific herring assessment model   总被引：2，自引：0，他引：2  

Hulson  Peter-John F.; Miller  Sara E.; Quinn  Terrance J.  II; Marty  Gary D.; Moffitt  Steven D.; Funk  Frederick 《ICES Journal of Marine Science》2008,65(1):25-43

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Evaluation of image-based multibeam sonar backscatter classification for benthic habitat discrimination and mapping at Stanton Banks,UK     

Chris McGonigle  Craig Brown  Rory Quinn  Jonathan Grabowski 《Estuarine, Coastal and Shelf Science》2009,81(3):423-437

In recent years, efforts have increased to develop quantitative, computer-directed methods for segmentation of multibeam (MBES) backscatter data. This study utilises MBES backscatter data acquired at Stanton Banks (UK) and subsequently processed through the QTC-Multiview software environment in a bid to evaluate the program's ability to perform unsupervised classification. Statistical comparison with ground-truth data (grab, stills and video) enabled cross validation of acoustic segmentation and biological assemblages observed at the site. 132 unspecified variables were extracted from user-specified rectangular patches of the backscatter image, reduced to three vectors by PCA, then clustered and classified by the software. Multivariate analyses of ground-truth data were conducted on 75 stills images and 51 grab samples. Video footage coincident with the stills was divided into 30 s segments and coded by dominant substrate and species. Cross tabulation determined the interrelationship between software classifications, multivariate analysis of the biological assemblages and coded video segments. Multiview optimally identified 19 classes using the automated clustering engine. These were revised to 6 habitats a posteriori, using combined analysis of ground-truth data and Multiview data products. These habitats broadly correspond to major physiographic provinces within the region. Multivariate statistical analysis reveals low levels of assemblage similarity (<35%) for samples occurring within Multiview classes, irrespective of the mode of acquisition. Coded video data is more spatially appropriate than the other methods of ground-truthing investigated, although it is less well suited to the extraction of truly quantitative data. Multivariate analysis indicates assemblages within physiographically distinct Multiview classes have a low degree of biological similarity, supporting the notion that abiotic proxies may be contraindicative of benthic assemblage variations. QTC-Multiview performs well as a mechanism for computer-assisted segmentation of MBES backscatter imagery into acoustic provinces; however a degree of caution is required prior to ascribing ecological significance to these classifications.  相似文献   

Geochemical distribution of hydrocarbons in sediments from mid-Narragansett Bay,Rhode Island     

Terry L. Wade  James G. Quinn 《Organic Geochemistry》1979,1(3):157-167

The concentration of hydrocarbons (saturated and aromatic) and synthetic chlorinated compounds (Chlordane, DDT, and PCBs) decreased with depth in sediment cores from mid-Narragansett Bay and reached background levels at different depths. These depths were in general agreement with those expected based on the chronological inputs of these materials to the Bay. Although the total hydrocarbons concentration decreased with depth, the biogenic n-alkanes (n-C_{25,27,29,31,33}) showed a fairly constant concentration with depth as did the organic carbon content of these sediments. The n-alkane odd/even ratio increased with depth in the cores. Size fractionation (> 45 μm and < 45 to > 0.3 μm) of two core sections showed more hydrocarbons associated with the smaller size fraction in the surface section, while the lower section had approximately equal concentrations in both fractions. These trends suggest that over the time period covered by these cores the inputs of biogenic materials has remained relatively constant, while the input of anthropogenic hydrocarbons has increased dramatically during the last 100 yr. This increase is probably due to the expanded use of petroleum over this time period and subsequent chronic inputs to this estuarine environment.  相似文献   

The solubility behaviour of No. 2 fuel oil in sea water     

P.D Boehm  J.G Quinn 《Marine pollution bulletin》1974,5(7):101-105

The solubility of No. 2 fuel oil in sea water is studied using gas chromatographic techniques. Evidence is presented for the existence of accommodated (particulate or droplet), solubilized (colloidal micelles) and soluble hydrocarbon components in fuel oil-sea water mixtures.  相似文献   

Great Lakes Hydrology Under Transposed Climates   总被引：3，自引：0，他引：3  

Thomas E. Croley II  Frank H. Quinn  Kenneth E. Kunkel  Stanley a. Changnon 《Climatic change》1998,38(4):405-433

Historical climates, based on 43 years of daily data from areas south and southwest of the Great Lakes, were used to examine the hydrological response of the Great Lakes to warmer climates. The Great Lakes Environmental Research Laboratory used their conceptual models for simulating moisture storages in, and runoff from, the 121 watersheds draining into the Great Lakes, over-lake precipitation into each lake, and the heat storages in, and evaporation from, each lake. This transposition of actual climates incorporates natural changes in variability and timing within the existing climate; this is not true for General Circulation Model-generated corrections applied to existing historical data in many other impact studies. The transposed climates lead to higher and more variable over-land evapotranspiration and lower soil moisture and runoff with earlier runoff peaks since the snow pack is reduced up to 100%. Water temperatures increase and peak earlier. Heat resident in the deep lakes increases throughout the year. Buoyancy-driven water column turnover frequency drops and lake evaporation increases and spreads more throughout the annual cycle. The response of runoff to temperature and precipitation changes is coherent among the lakes and varies quasi-linearly over a wide range of temperature changes, some well beyond the range of current GCM predictions for doubled CO₂ conditions.  相似文献   

Magnetic properties of feroxyhyte (δ-FeOOH)     

C. Bender Koch  C. A. Oxborrow  S. Mørup  M. B. Madsen  A. J. Quinn  J. M. D. Coey 《Physics and Chemistry of Minerals》1995,22(5):333-341

Magnetization curves and high-field Mössbauer spectra are used to deduce a model for the magnetic order in synthetic samples of δ-FeOOH (feroxyhyte), which takes account of the changes in magnetization when the samples are heated at 105 °C. Feroxyhyte is essentially a planar antiferromagnet with the net sublattice moments aligned parallel or antiparallel to c. Each particle acquires a net moment due to the very small number of layers along the c-direction, and the presence of surface steps causing the formation of ferrimagnetic domains with an odd number of layers. There is some spin canting which is related to the crystallinity of the sample. The decrease in magnetization following heating is mainly due to an increase in the extent of antiferromagnetic coupling between the closely packed ferrimagnetic particles, but changes in the spin canting within the bulk may also contribute. A typical, rather well crystallized specimen has magnetization σ=14 JT^?1 kg^?1 and Curie temperature T _c=455 K.  相似文献   

Simulations of the Viking Gas Exchange Experiment using palagonite and Fe-rich montmorillonite as terrestrial analogs: implications for the surface composition of Mars     

Quinn R  Orenberg J 《Geochimica et cosmochimica acta》1993,57(19):4611-4618

Simulations of the Gas Exchange Experiment (GEX), one of the Viking Lander Biology Experiments, were run using palagonite and Fe-rich montmorillonite as terrestrial analogs of the Martian soil. These terrestrial analogs were exposed to a nutrient solution of the same composition as that of the Viking Landers under humid (no contact with nutrient) and wet (intimate contact) conditions. The headspace gases in the GEX sample cell were sampled and then analyzed by gas chromatography under both humid and wet conditions. Five gases were monitored: CO2, N2, O2, Ar, and Kr. It was determined that in order to simulate the CO2 gas changes of the Viking GEX experiment, the mixture of soil analog mineral plus nutrient medium must be slightly (pH = 7.4) to moderately basic (pH = 8.7). This conclusion suggests constraints upon the composition of terrestrial analogs to the Mars soil; acidic components may be present, but the overall mixture must be basic in order to simulate the Viking GEX results.  相似文献   

Shipboard sunphotometer measurements of aerosol optical depth spectra and columnar water vapor during ACE‐2, and comparison with selected land, ship, aircraft, and satellite measurements     

John M. Livingston  Vladimir N. Kapustin  Beat Schmid  Philip B. Russell  Patricia K. Quinn  Timothy S. Bates  Philip A. Durkee  Peter J. Smith  Volker Freudenthaler  Matthias Wiegner  Dave S. Covert  Santiago Gassó  Dean Hegg  Donald R. Collins  Richard C. Flagan  John H. Seinfeld  Vito Vitale  Claudio Tomasi 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):594-619

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