Characterizing the distribution of observed precipitation and runoff over the continental United States     

Jayne Dolph  Danny Marks 《Climatic change》1992,22(2):99-119

This paper describes the development of a comprehensive geographic database of historical precipitation and runoff measurements for the conterminous U.S. The database is used in a spatial analysis to characterize large scale precipitation and runoff patterns and to assess the utility and limitations of using historical hydro-meteorological data for providing spatially distributed precipitation estimates at regional and continental scales. Long-term annual average precipitation (P) and runoff (Q) surfaces (geographically referenced, digital representations of a continuous spatial distribution) generated from interpolation of point measurements are used in a distributed water balance calculation to check the reliability of precipitation estimates. The resulting input-output values (P- Q) illustrate the deficiency (sparse distribution and low elevation bias) of historical precipitation measurements in the mountainous western U.S. where snowmelt is an important component of the annual runoff. The incorporation of high elevation snow measurements into the precipitation record significantly improves the water balance estimates in some areas and enhances the utility of historical data for providing spatially distributed precipitation estimates in topographically diverse regions. Regions where the use of historical precipitation data may be most limited for precipitation estimation are identified and alternatives to the use of interpolated historical data for precipitation estimation across large heterogenous regions are suggested. The research establishes a database for continental scale studies and provides direction for the successful development of spatially distributed regional scale water balance models.  相似文献   

Modeling the dynamics of the land-sea breeze circulation for air quality modeling   总被引：1，自引：0，他引：1  

Mikhail Novitsky  Danny D. Reible  Bernardo M. Corripio 《Boundary-Layer Meteorology》1992,59(1-2):163-175

Conventional atmospheric dispersion and air quality models require that the wind field be known with a higher resolution than is currently available from field monitoring stations in most coastal areas. In this paper, a numerical model is developed to predict the wind flow field during the land-sea breeze. The form and assumptions and method of solution of the model are described. The model output is compared to atmospheric data taken from a field study conducted in the Santa Barbara Channel and Ventura-Oxnard plain in southern California.  相似文献   

Laboratory simulation of diffusion in contaminated marine sediments     

Julie A. Baron  Louis J. Thibodeaux  Danny D. Reible  Paul H. Templet  Charles B. Henry 《Estuaries and Coasts》1990,13(1):81-88

Wastes from offshore oil drilling activities are often discharged to the marine environment. Solid wastes that settle onto the bottom sediment may pose a health threat to marine organisms and eventually to man through the food chain. We need to understand their fate in order to predict the chemical concentration levels and life-times in the sediment and adjoining aquatic boundary layer. A laboratory simulation of selected in-bed processes that addresses contaminant leaching from the sediment is proposed. The process chosen for simulation in this study is the coupled desorption-diffusion of contaminants from the bed to the water column. A simple mathematical model of the process is also proposed. Preliminary results using organic chemicals for both the simulation and the model are presented. The results suggest that the experimental procedure represents a good way of estimating the diffusive leaching rates of hydrophobic compounds from contaminated sediments.  相似文献   

Transient climatic response to an increase of greenhouse gases     

L. D. Danny Harvey 《Climatic change》1989,15(1-2):15-30

The physical factors governing the transient climatic response to an increase of greenhouse gases are discussed, reasons for remaining uncertainties are identified, and recent climate modelling results are briefly summarized. The relevance of the transient response, and of uncertainties in the transient response, to questions such as the applicability of equilibrium climate model simulations to a gradual greenhouse gas increase, the verification of model projections, rates of climatic change, and the impacts of preventative strategies for dealing with the buildup of greenhouse gases is also discussed.  相似文献   

High integrated fluid rock ratios during metamorphism at Naxos: evidence from carbon isotopes of calcite in schists and fluid inclusions     

J. Ben H. Jansen  Henk Van der Rijst  Robert O. Rye  Paul A. M. Andriessen  Danny M. Rye 《Contributions to Mineralogy and Petrology》1989,103(1):123-126

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The βFeOOH to αFe2O3 phase transformation: Structural and magnetic phenomena     

Danny G. Chambaere  Eddy De Grave 《Physics and Chemistry of Minerals》1985,12(3):176-184

It is shown that under ambient atmospheric conditions heating causes the crystal structure of βFeOOH (synthetic akaganeite) to degenerate gradually into a quasi amorphous intermediate state, before the final phase transformation to αFe₂O₃ (hematite) takes place. Using X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Mössbauer Spectroscopy, this amorphization process is monitored and the structural, morphological and magnetic features of the intermediate phase as a function of the isochronal heating temperature are discussed: the crystallites develop macropores on their surface, the adsorption capacity raises up to 10 percent of the initial mass, a third type of Fe³⁺ coordination, having an extremely large quadrupole splitting, is created and the Néel temperature, after an initial decrease, exhibits a sharp increase at higher heating temperatures. The magnetic behaviour of this intermediate phase at low temperatures and in high external fields suggests this antiferromagnet undergoes magnetic phase transitions (metamagnetism and spin flop) at unusually low critical fields.  相似文献   

Book reviews     

Jill Jäger  J. Oerlemans  Dario Camuffo  A. J. Semtner Jr.  Tom Bettge  L. D. Danny Harvey 《Climatic change》1986,8(2):189-199

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Variation of initial Th/Th and limits of high precision U-Th dating of shallow-water corals     

Chuan-Chou Shen  Kuei-Shu Li  Danny Natawidjaja  Xianfeng Wang  Doan Dinh Lam  Tung-Yung Fan  Fred W. Taylor  Hong-Wei Chiang 《Geochimica et cosmochimica acta》2008,72(17):4201-4223

One hundred eighty U-Th data, including 23 isochrons on 24 pristine modern and Holocene corals and 33 seawater samples, were analyzed using sector-field mass spectrometry to understand the variability of initial ²³⁰Th/²³²Th (²³⁰Th/²³²Th₀). This dataset allows us to further assess the accuracy and precision of coral ²³⁰Th dating method. By applying quality control, including careful sampling and subsampling protocols and the use of contamination-free storage and workbench spaces, the resulting low procedural blanks give an equivalent uncertainty in age of only ±0.2-0.3 yr for 1-2 g of coral sample. Using site-specific ²³⁰Th/²³²Th₀ values or isochron techniques, our study demonstrates that corals with an age less than 100 yrs can be ²³⁰Th-dated with precisions of ±1 yr. Six living subtidal coral samples were collected from two continental shelf sites, Nanwan off southern Taiwan in the western Pacific and Son Tra off central Vietnam in the South China Sea; one coral core was drilled from an open-ocean site, Santo Island, Vanuatu, in the western tropical Pacific; and modern and fossil intertidal coral slabs, 17 in total, were cut from six sites around the islands of Simeulue, Lago, North Pagai and South Pagai of Sumatra in the eastern Indian Ocean. The results indicate that the main source of thorium is the dissolved phase of seawater, with variation of ²³⁰Th/²³²Th₀ depending on local hydrology. With intense input of terrestrial material, low ²³⁰Th/²³²Th₀ atomic ratios of 4.9 × 10⁻⁶ and 3.2 × 10⁻⁶ with a 10% variation are observed in Nanwan and Son Tra, respectively. At the Santo site, we find a value of 5.6 × 10⁻⁶ at 4 horizons and one high value of 24 × 10⁻⁶ in a sample from AD 1974.6 ± 0.5, likely due to the upwelling of cold water during a La Niña event between AD 1973 and 1976. The natural dynamics of ²³⁰Th/²³²Th₀ recorded in the intertidal corals at sites in the Sumatran islands are complicated so that this value varies significantly from 3.0 to 9.4 × 10⁻⁶. Three of the 141 modern coral ²³⁰Th ages differ from their true ages by −23 to +4, indicating the presence of detrital material with anomalous ²³⁰Th/²³²Th values. Duplicate measurement of coeval subsamples is therefore recommended to verify the age accuracy. This improved high precision coral ²³⁰Th dating method raises the prospects of refining the age models for band-counted and tracer-tuned chronologies and of advancing coral paleoclimate research.  相似文献   

Toxic volatile organic air pollutants across Canada: multi-year concentration trends,regional air quality modelling and source apportionment     

Craig A. Stroud  Calin Zaganescu  Jack Chen  Chris A. McLinden  Junhua Zhang  Danny Wang 《Journal of Atmospheric Chemistry》2016,73(2):137-164

A Unified Regional Air-quality Modelling System, AURAMS, was expanded to predict six toxic volatile organic compounds (VOCs) within a continental domain and two nested domains covering eastern and western Canada. The model predictions were evaluated against Environment Canada’s National Air Pollution Surveillance (NAPS) data set to assess the predictive capability of the model at daily and seasonal time scales. The predictions were also evaluated with satellite-derived column total maps for formaldehyde, carbon monoxide, and nitrogen dioxide. In general, the model showed fair to good predictive skill in terms of both correlation (R) and normalized mean bias (NMB) for benzene (R = 0.53 NMB = 26 %), formaldehyde (R = 0.73, NMB = ?15 %) and acetaldehyde (R = 0.55, NMB = 29 %). For the other toxics VOCs, the model showed less predictive skill in the order 1,2,4-trimethylbenzene (R = 0.50, NMB = ?41 %), 1,3-butadiene (R = 0.26, NMB = 40 %) and acrolein (R = 0.052, NMB = ?51 %). The goal of this study was to apply an air quality model to assess the contribution of mobile sources to ambient levels of toxic VOCs at urban locations across Canada. The mobile source contribution varied in a complex manner for each species for different regions. For benzene and 1,2,4-trimethylbenzene, the mobile source contribution was in the range 40–65 % for major Canadian cities. The model predicted considerably lower mobile source contributions for rural locations in the Canadian Prairies, where other area sources dominate, such as the petrochemical industry. Measured concentration trends in toxics are also presented from 2004 to 2010. The primary emitted toxics declined gradually (13–16 % over 6 yr) whereas the toxic aldehydes showed no trend.  相似文献   

Flow and transport modeling in the sea-breeze part II: Flow model application and pollutant transport   总被引：2，自引：0，他引：2  

Youn-Seo Koo  Danny D. Reible 《Boundary-Layer Meteorology》1995,75(3):209-234

A modifiedE- non-hydrostatic model with non-equilibrium level 2.5 closure was applied to the flow and pollutant dynamics in the sea-breeze. The model predicts key observed characteristics of the sea-breeze, such as midday slowing of inland penetration, fast and deep inland penetration in late afternoon, and detachment of the sea-breeze from the feeding flow in early evening. In late evening when the turbulent mixing over the land subsides due to the surface cooling, a frontal density current is formed and the predicted structure is in good agreement with observations and laboratory experiments of density currents. Turbulent mixing over the land is a key parameter that controls midday slowing and late afternoon frontal development.The calculated thermal internal boundary layer and fumigation of an elevated line source show good agreement with observations and similarity theory. Calculations suggest that the residual plume aloft over the sea returns onshore at ground level during the afternoon sea-breeze and has a large impact on ground-level concentrations during the following day.  相似文献