In the wake of the Polar Sea : Canadian jurisdiction and the northwest passage     

Ted L. McDorman 《Marine Policy》1986,10(4)

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Editorial: Social geography     

Ted Yates 《GeoJournal》1984,9(3):215-222

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Using on‐nadir spectral reflectance to detect soil surface changes induced by simulated rainfall and wind tunnel abrasion     

Adrian Chappell  Ted M. Zobeck  Gillian Brunner 《地球表面变化过程与地形》2005,30(4):489-511

The surface susceptibility to erosion (erodibility) is an important component of soil erosion models. Many studies of wind erosion have shown that even relatively small changes in surface conditions can have a considerable effect on the temporal and spatial variability of dust emissions. One of the main difficulties in measuring erodibility is that it is controlled by a number of highly variable soil factors. Collection of these data is often limited in scale because in situ measurements are labour‐intensive and very time‐consuming. To improve wind erosion model predictions over several spatial and temporal scales simultaneously, there is a requirement for a non‐invasive approach that can be used to rapidly assess changes in the compositional and structural nature of a soil surface in time and space. Spectral reflectance of the soil surface appears to meet these desirable requirements and it is controlled by properties that affect the soil erodibility. Three soil surfaces were modified using rainfall simulation and wind tunnel abrasion experiments. Observations of those changes were made and recorded using digital images and on‐nadir spectral reflectance. The results showed clear evidence of the information content in the spectral domain that was otherwise difficult to interpret given the complicated interrelationships between soil composition and structure. Changes detected at the soil surface included the presence of a crust produced by rainsplash, the production of loose erodible material covering a rain crust and the selective erosion of the soil surface. The effect of rainsplash and aeolian abrasion was different for each soil tested and crust abrasion was shown to decrease as rainfall intensity increased. The relative contributions of the eroded material from each soil surface to trapped mixtures of material assisted the erodibility assessment. Ordination analyses within each of two important soil types explained significant amounts of the variation in the reflectance of all wavebands by treatments of the soil and hence changes in the soil surface. The results show that soil surface conditions within a soil type are an underestimated source of variation in the characterization of soil surface erodibility and in the remote sensing of soil. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

A Field Test of Visually Clear Casing for Subsurface Inspection     

Ted Lizanec Jr.  Liam Fahey 《Ground Water Monitoring & Remediation》1996,16(3):76-78

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Search for the 3.4-μm C-H Spectral Bands on Low-Albedo Asteroids     

Dale P. Cruikshank  Thomas R. GeballeTobias C. Owen  Cristina M. Dalle OreTed L. Roush  Robert H. BrownJohn H. Lewis 《Icarus》2002,156(2):434-441

A report of the detection of the C-H hydrocarbon band complex at 3.4 μm in an asteroid spectrum, by D. P. Cruikshank and R. H. Brown (1987, Science238, 183-184) is not confirmed by recent data of higher quality. Spectra of the same asteroid and six other low-albedo asteroids do not show this feature, which if present would indicate the presence of hydrocarbons and might link these asteroids with certain classes of carbonaceous meteorites.  相似文献   

Primary production, plant and detrital biomass, and particle transport in the Columbia River Estuary     

Lawrence F. Small  C.David McIntire  Keith B. MacDonald  J.Ruben Lara-Lara  Bruce E. Frey  Michael C. Amspoker  Ted Winfield 《Progress in Oceanography》1990,25(1-4)

The dynamics of primary production and particulate detritus cycling in the Columbia River Estuary are described, with particular reference to mechanisms that account for patterns within the water column, on the tidal flats, and in the adjacent wetlands. Analysis of patterns in phytoplankton flora and biomass and in distribution of detrital particulate organic matter (DPOC) in the water column indicated that salinities of 1–5 delineated an essentially freshwater flora from a marine or euryhaline flora, and that living phytoplankton was converted to DPOC at the freshwater-brackishwater interface. Similarly, the benthic diatom assemblages on tidal flats reflected either the fresh or the brackish nature of the water inundating the flats. Emergent vascular plants were grouped into six associations by cluster analysis, the associations being separated mainly on the bases of different relative abundances of freshwater, euryhaline or brackishwater species, and on whether samples occurred in high or low marsh areas.Annual rates of net areal 24-hr production averaged 55, 16, and 403gC m⁻²y⁻¹ for phytoplankton, benthic algae, and emergent vascular vegetation, respectively. Total production over the whole estuary was 17,667 metric tons C y⁻¹ for phytoplankton, 1,545mt C y⁻¹ for benthic algae, and 11,325mt C y⁻¹ for emergent vascular plants, for a grand total to 30,537mt C y⁻¹. Phytoplankton biomass turned over approximately 39 times per year on average, while benthic algae turned over about twice and emergent plants once per year.Budgets for phytoplankton carbon (PPOC) and DPOC were developed based on PPOC and DPOC import and export, grazing loss, and in situ production and conversion of PPOC to DPOC. It is suggested that 36,205mt y⁻¹ of PPOC is converted to DPOC in the estuary, principally at the freshwater-brackishwater interface. About 40,560mt y⁻¹ of PPOC is exported to the ocean, and 159,185mt y⁻¹ of DPOC is transported into the marine zone of the estuary (no data are available on DPOC export to the ocean). Thus, the estuary acts principally as a conduit for the transport of particles to the sea, and only secondarily as a converter of viable phytoplankton cells to detrital carbon and as a trap for DPOC.  相似文献   

MODELING OF RIVER MORPHOLOGIC CHANGES     

Charles C. S. SONG  Yifan ZHENG    Chih Ted YANG 《国际泥沙研究》1995,(2)

ＭＯＤＥＬＩＮＧＯＦＲＩＶＥＲＭＯＲＰＨＯＬＯＧＩＣＣＨＡＮＧＥＳＣｈａｒｌｅｓＣ．Ｓ．ＳＯＮＧ；ＹｉｆａｎＺＨＥＮＧ；ａｎｄＣｈｉｈＴｅｄＹＡＮＧ（Ｐｒｏｆｅｓｓｏｒ，Ｓｔ．ＡｎｔｈｏｎｙＦａｌｌｓＨｙｄｒａｕｌｉｃＬａｂｏｒａｔｏｒｙ，Ｄｅｐａｒ...  相似文献   

Chemical studies of L chondrites—III. Mobile trace elements and ${}^{40}\text{Ar}{}^{39}\text{Ar}$ ages     

Ted J Huston  Michael E Lipschutz 《Geochimica et cosmochimica acta》1984,48(6):1319-1329

We report data for trace elements Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Se, Te, Tl and Zn determined by radiochemical neutron activation analysis in L4–6 chondrites with undisturbed ⁴⁰Ar release patterns or with patterns showing some disturbance in the 4.4–4.6 Gyr plateau indicating shock-induced loss. Mean concentrations are lower, many significantly so, in 16 chondrites with disturbed patterns than in 4 with undisturbed ones, consistent with shock-induced mobilization. Similar trends were noted earlier in L4–6 chondrites having mineralogically observable shock indicators: mean concentrations are lower in strongly shocked (i.e. > 22 GPa) than in mildly shocked (<22 GPa) samples. From trace element contents, L4–6 chondrites with undisturbed ⁴⁰Ar release patterns are mildly shocked but chondrites with disturbed patterns are more strongly heated, on average, than those of shock facies d-f (i.e. 22 to > 57 GPa). Pooling these populations, significantly lower mean concentrations of nearly all trace elements in 26 strongly shocked L4–6 chondrites than in 14 mildly shocked ones indicate loss in shock-formed FeS-Fe eutectic and/or by vaporization during cooling of shock-heated collisional debris. Two-element correlations and the pattern of them, i.e. correlation profiles, are also consistent with this picture. Trace elements can act as thermometers for collisional episodes in L4–6 chondrites but not for earlier thermal fractionations, unless compensation can be made for late shock heating.  相似文献   

OPTIMUM CHANNEL GEOMETRY AND MINIMUM ENERGY DISSIPATION RATE   总被引：2，自引：0，他引：2  

Chih Ted Yang  Charles C. S. Song International  Special Projects Coordinator  U. S. Bureau of Reclamation  Denyer  Colorado  U. S. A. Professor  St. Anthony Falls Hydraulic Laboratory  University of Minnesota  MinneaPOlis  Minnesota  U. S. A. 《国际泥沙研究》1990,(1)

1. INTRODUCTIONA natural river adjusts its roughness, channel geometry, slope I length, and Pattern to changing hydrologic, geologic, and manmade conditions. However, some sort of mean condition or quasi-equilibriumcondition appears to exist for natural streams. The earliest attempts to describe the quasi--equlibrium geometry of rivers were the empirical approaches, such as the regime approach proposed by Lacey (1929) andLeoPOld et al. (1953 ). Later, theoretical approaches based on the…  相似文献   

Reply to Jurdy & Stefanick comment     

Ted Chang  Joann Stock  Peter Molnar 《Geophysical Journal International》1992,110(1):215-217

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