Transport of gases and particles to surfaces with widely spaced roughness elements   总被引：1，自引：0，他引：1  

A. C. Chamberlain  J. A. Garland  A. C. Wells 《Boundary-Layer Meteorology》1984,29(4):343-360

Radioactive gases and labelled particles have been used in wind tunnels to measure the effects of Reynolds and Schmidt numbers on transport to surfaces with widely spaced roughness elements. Good correlations are obtained for gases and for sub-micrometric sized particles, and the results can probably be extended to conditions in the open air. Deposition of larger particles is dominated by the effects of bounce off, which depends on surface conditions. This is also reflected in the pattern of deposition between roughness elements.  相似文献   

Marine Layer Stratus Study     

Leonard A. Wells 《Pure and Applied Geophysics》2007,164(6-7):1397-1421

The intent of this study is to develop a better understanding of the behavior of late spring through early fall marine layer stratus and fog at Vandenberg Air Force Base, which accounts for a majority of aviation forecasting difficulties. The main objective was to use Leipper (1995) study as a starting point to evaluate synoptic and mesoscale processes involved, and identify specific meteorological parameters that affected the behavior of marine layer stratus and fog. After identifying those parameters, the study evaluates how well the various weather models forecast them. The main conclusion of this study is that weak upper-air dynamic features work with boundary layer motions to influence marine layer behavior. It highlights the importance of correctly forecasting the surface temperature by showing how it ties directly to the wind field. That wind field, modified by the local terrain, establishes the low-level convergence and divergence pattern and the resulting marine layer cloud thicknesses and visibilities.  相似文献   

Marine forecasting. Predictability and modelling in ocean hydrodynamics. Proceedings of the 10th international liège colloquium on ocean hydrodynamics: J.C.J. Nihoul (Editor). Elsevier Oceanography Series, 25. Elsevier,Amsterdam, 1978, xiv + 494pp., ISBN 0-444-41797-4. Dfl. 130.00, U.S. $ 66.75     

N.C. Wells 《Dynamics of Atmospheres and Oceans》1980,4(3):217-218

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The hydrogeologic connectivity of a low-flow saline-spring fen peatland within the Athabasca oil sands region,Canada     

Corey M. Wells  Jonathan S. Price 《Hydrogeology Journal》2015,23(8):1799-1816

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The measurement and modelling of rill erosion at angle of repose slopes in mine spoil   总被引：2，自引：0，他引：2  

G. R. Hancock  D. Crawter  S. G. Fityus  J. Chandler  T. Wells 《地球表面变化过程与地形》2008,33(7):1006-1020

The process of rill erosion causes significant amounts of sediment to be moved in both undisturbed and disturbed environments and can be a significant issue for agriculture as well as mining lands. Rills also often develop very quickly (from a single rainfall event to a season) and can develop into gullies if sufficient runoff is available to continue their development. This study examines the ability of a terrestrial laser scanner to quantify rills that have developed on fresh and homogeneous mine spoil on an angle of repose slope. It also examines the ability of the SIBERIA erosion model to simulate the rill's spatial and temporal behaviour. While there has been considerable work done examining rill erosion on rehabilitated mine sites and agricultural fields, little work has been done to examine rill development at angle of repose sites. Results show that while the overall hillslope morphology was captured by the laser scanner, with the morphology of the rills being broadly captured, the characteristics of the rills were not well defined. The digital elevation model created by the laser scanner failed to capture the rill thalwegs and tops of the banks, therefore delineating a series of ill defined longitudinal downslope depressions. These results demonstrate that an even greater density of points is needed to capture sufficient rill morphology. Nevertheless, SIBERIA simulations of the hillslope demonstrated that the model was able to capture rill behaviour in both space and time when correct model parameters were used. This result provides confidence in the SIBERIA model and its parameterization. The results demonstrate the sensitivity of the model to changes in parameters and the importance of the calibration process. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Introduction     

E. Christian Wells  Richard E. Terry 《Geoarchaeology》2007,22(3):285-290

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Reflection of equatorial Kelvin waves at eastern ocean boundaries Part II: Pacific and Atlantic Oceans     

J. Soares  I. Wainer  N. C. Wells 《Annales Geophysicae》1999,17(6):827-837

The effect of viscosity, non linearities, incident wave period and realistic eastern coastline geometry on energy fluxes are investigated using a shallow water model with a spatial resolution of 1/4 degree in both meridional and zonal directions. Equatorial and mid-latitude responses are considered. It is found that (1) the influence of the coastline geometry and the incident wave period is more important for the westward energy flux than for the poleward flux, and (2) the effect of the inclination of the eastern ocean boundary on the poleward energy flux, for the Pacific and Atlantic Oceans, decline as the period of the incident wave increases. Furthermore, the model simulations suggest that the poleward energy fluxes from meridional boundaries give plausible results for motions of seasonal and annual periods. For comparatively shorter periods, a realistic coastline geometry has to be included for more accurate results. It is recommended that any numerical model involving the reflection of baroclinic Rossby waves (of intraseasonal, seasonal or annual periods) on the eastern Pacific or Atlantic Oceans, should consider the effect of the coastline geometry in order to improve the accuracy of the results.  相似文献   

Internal waves revealed by Synthetic Aperture Radar (SAR) imagery in the vicinity of the eastern Cretan Arc Straits (Eastern Mediterranean)     

A. F. Velegrakis  E. Oikonomou  A. Theocharis  M. B. Collins  H. Kontoyiannis  V. Papadopoulos  G. Voulgaris  T. Wells  E. Balopoulos 《Progress in Oceanography》1999,44(4):1131

Internal waves have been detected on ERS-1 SAR images obtained during late summer over the eastern Cretan Straits, an area characterised by complex regional physiography, bottom topography, flow regime and stratification patterns of the upper part of the water column. Analysis of the imaged characteristics of the internal waves has revealed a strong diversity in form, propagation direction and type of sea surface modulation, which indicates various mechanisms of generation. Analysis of the currents recorded over the area shows that, although semi-diurnal tidal currents are present, these are of low magnitude in comparison with the overall flow and, therefore, tidal forcing is unlikely to be a major process in the generation of the imaged internal waves. In addition, a well-defined front has been identified within the Rhodes Strait. This front is considered to be the surficial manifestation of the Asia Minor Current, which is a strong and persistent large-scale circulation feature of the Eastern Mediterranean.  相似文献   

Ten Years of Studies on Maryland's Inner Continental Margin and Coastal Bays     

Randall T. Kerhin  Robert Conkwright  Darlene Wells 《Marine Georesources & Geotechnology》1999,17(2):127-137

During the past ten years of the Association of American State Geologists-Mineral Management Service Continental Margins Program, the Maryland Geological Sur vey investigated the sedimentological, paleontological, stratigraphical and geophysi cal character of Maryland's inner continental shelf. Based on seismic records and sedimentological analyses completed during the first four years, a late Quaternary stratigraphic model was developed. Five distinct stratigraphic units were identified and described on the Maryland inner shelf. These units represent late Pleistocene interglacial deposits, the oldest of which corresponds to pre-Illinoian (oxygen-isotope stages 7 and or 9) transgressive shelf sands. Overlying the Q1 unit, the Q2 unit is a 6-meter thick mud sequence of oxygen-isotope stage 5 (128-75 ka) age. Units Q3 and Q4 representing fluvial and leading edge estuarine deposits (oxygen-isotope stages 4, 3 and 2) filled numerous paleochannels that were incised into units Q2 and Q1. Modern trailing-edge transgressive shelf shoals (Unit Q5) discontinuously cap the sequence. The 5th and 6th years studies reported on the economic minerals of surficial and cored sediments. Vibracores collected off the Maryland's shelf during previous studies were analyzed for mineral types and abundances, weight percent of general size fractions, and heavy mineral (HM) content. Mineralogic maturity indices were compiled to correlate the THM and economic heavy minerals (EHM) abundances with position offshore, sediment type, and the indices themselves. For the 7th year, the Maryland Geological Survey re-examined geophysical records and lithological data originally collected by the Army Corps of Engineers to locate and assess beach fill borrow areas for the Ocean City Beach Replenishment Project. Data from 163 vibracores and over 300 kilometers of high-resolution seismic profile records collected off Ocean City, Maryland, supported the strati graphic model developed by MGS during the first four years of the AASG-MMS program. The Maryland coastal bays became the focus of study during the 8th and 9th years during which seismic records, cores and surficial sediment were collected in Isle of Wight and Assawoman Bays. Shallow pretransgression surface was mapped, relating the existing streams to offshore paleochannels. The tenth year study focused on developing a repository for vibracores collected on Maryland's inner continental shelf.  相似文献   

Bioenergetic modelling of the marine phase of Atlantic salmon (Salmo salar L.)     

I. Philip Smith  Douglas J. Booker  Neil C. Wells 《Marine environmental research》2009,67(4-5):246-258

A bioenergetic model of marine phase, wild Atlantic salmon was constructed to investigate the potential effects on post-smolt growth of predicted changes in oceanic conditions. Short-term estimates of growth in weight were similar to measurements in captivity and simulated growth varied with water temperature and swimming speed as expected. Longer-term estimates of growth in length were less than that achieved by wild salmon, particularly with constant swimming assumed. The model was sensitive to parameters relating to maximum daily food consumption, respiration and the relationships between body energy content, length and weight. Some of the sensitive parameters were based on substantive information on Atlantic salmon and their realistic ranges are likely to be much narrower than those tested. However, other parameter values were based on scant data, farmed Atlantic salmon or other salmonid species, and are therefore less certain and indicate where future empirical research should be focussed.  相似文献