Book review     

David J. Campbell 《Climatic change》1995,29(2):247-249

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Satellite monitoring of sea surface temperatures off China     

Legeckis  Richard  Campbell  Joan 《中国海洋湖沼学报》1988,6(3):243-250

Satellite measurements of global sea surface temperatures (SST) have been made since 1982 using the multi-channel radiometers (AVHRR) on NOAA polar orbiting satellites. A four year data set was accumulated at daily intervals and a spatial resolution of about 100 kilometers on an interactive computer system. The time lapse evaluation of the data revealed variations of the SST which were related to coastal and equatorial upwelling events as well as to the pronounced equatorial warming associated with the 1982–1983 El Niño. In the present study, satellite time series are used to describe the annual variability of the SST at selected locations along the coast of China, the Yellow Sea, the Sea of Japan and the Equatorial Indian and Pacific Oceans. Further study of the SST off China using higher resolution satellite data are also described.

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Study of evaporation and recharge in desert soil using environmental tracers, New Mexico, USA   总被引：4，自引：0，他引：4  

A.-R. Shurbaji  A. R. Campbell 《Environmental Geology》1997,29(3-4):147-151

 The purpose of this study is to investigate the rates and mechanisms of recharge and evaporation in soils of a desert environment using two environmental tracers (chloride and oxygen-18). The profiles of chloride concentration and oxygen-18 enrichment in soil-water, together with the depth distribution of water content in soil, reveal information about long-term recharge and instantaneous evaporation processes without needing to know the physical properties of the soil. Three holes were hand-augured, in different desert settings in southeastern New Mexico. The chloride concentration profiles were used, with the chloride mass balance method, to estimate long-term recharge rates in these three holes as 0.5, 0.8, and 2.4 mm yr^–1. Analysis using a bimodal flow and transport model shows that possibly 85% of the recharge occurs via movement of water through preferred pathways in the root zone. Preferential flow was evident in all three sampling sites. Clay layers have a noticeable effect on the development of water content distribution and thus on oxygen-18 enrichment and chloride concentration profiles. The spatial variation in clay layering partly explains the variation in recharge rate estimates. Received: 13 October 1995 · Accepted: 15 November 1995  相似文献   

Transient convective waves in the tropical SW Indian Ocean     

M. R. Jury  B. Pathack  G. Campbell  B. Wang  W. Landman 《Meteorology and Atmospheric Physics》1991,47(1):27-36

Summary Wave-organized convective features in the southwest Indian Ocean are described using Hovmoller composites of satellite imagery, OLR anomalies and ECMWF precipitable water departures during the southern summer. Westward movement of large convective elements is noted in the 10–20°S latitude band in about half of the years between 1970 and 1984. A study of 47 convective systems from satellite imagery establishes the climatological features, including zonal propagation speeds for maritime systems in the range –2 to –4 m s^–1, wavelengths of 25–35° longitude (3,000 km), lifespans of 10–20 days and convective areas of 7–10° longitude (800 km). Transient convective waves over the tropical SW Indian Ocean are slower and more diverse than their northern hemisphere counterparts. Interannual tendencies in the frequency and mode are studied. Wet summers over SE Africa correspond with an increased frequency of westward moving convective systems, whereas in dry summers convective systems tend to be quasi-stationary. INSAT data composites provide additional insight into the convective structure and show that tropical waves penetrated into southern Africa in February 1988. A more quantitative assessment of transient convective waves is provided by Hovmoller composites of OLR anomalies and precipitable water departures. Both display westward moving systems in 1976 and 1984 and highlight the wide variety and mixed mode character of convective waves. A case study is analyzed which illustrates the deepening of a moist, unstable layer coincident with the westward passage of a convective wave.With 12 Figures  相似文献   

Classification of rock weathering at writing-on-stone Provincial Park,Alberta, Canada: A study in applied geomorphology     

Ian A. Campbell 《地球表面变化过程与地形》1991,16(8):701-711

At Writing-On-Stone Provincial Park in southern Alberta, Canada, weathering is causing deterioration and loss of archaeologically important Indian rock art. A procedure devised for the use of park personnel identified four classes of weathering ranging from largely unweathered rock to severely weathered. The technique employed simple visual, qualitative assessment and photo interpretation of 50 sample sections of sandstone cliff face covering a total area of 354 m². Schmidt hammer tests indicated large variations in rock strength and provided a numerical basis for the visual assessment. About 43 per cent of the cliffs are severely to completely weathered, 41 per cent show moderate weathering.  相似文献   

The behaviour of platinum group elements in the surficial environment at Ferguson Lake, N.W.T., Rottenstone Lake, Sask. and Sudbury, Ont., Canada     

W.B. Coker  C.E. Dunn  G.E.M. Hall  A.N. Rencz  R.N.W. DiLabio  W.A. Spirito  J.E. Campbell 《Journal of Geochemical Exploration》1991,40(1-3)

A multidisciplinary geochemical study of the distribution, dispersion, and glacial dispersal, of the pge and associated elements has been undertaken within soil, till, humus, vegetation and water at Ferguson Lake, Northwest Territories, Rottenstone Lake, Saskatchewan and Sudbury, Ontario.As the pge generally are present at low levels in surficial materials, development work on analytical techniques was an essential part of this study.At Ferguson Lake, the spatial distribution patterns of Au, Pt and Pd in till clearly indicate the exposed gossan zones, as expected, but also indicate a possible extension of the zone beneath a peat bog- and till-covered area. Down-ice dispersal of Au, Pt and Pd is limited to one to two hundred metres, in the <63 μm component of the till samples collected from frost boils. In vegetation the pge enrichment extends for several hundred metres down-ice and is best defined by Pd in birch twigs. Detectable, although extremely low, levels of Pt (2.8 ppt) and Pd (2.0 ppt) are present in waters in the vicinity of the gossanous zones at Ferguson Lake.At Rottenstone Lake, moderate to high concentrations of pge, Au, and base metals were found in ashed twigs of black spruce and the hmc of the tills for a distance of less than two hundred metres down-ice of the mineralization. Low Pd and Au concentrations were present in ashed spruce twigs about one kilometre down-ice of the mineralization, where only the hmc of the tills yielded anomalous concentrations of Pt and Au. There appears to be only limited dispersal of the pge and Au. These data indicate that only the hmc and the spruce twigs are of value in detecting Pt and Au in this area. Palladium presents a different picture, being detectable in only some of the soils, absent in the tills and hmc, yet appreciably enriched in the twig ash. The inference is that Pd is moving in solution and is being somewhat adsorbed in the soil but is much more significantly being taken up by the plant roots.At the Sudbury areas the pge, hosted in the Ni-Cu mineralization, are best reflected by elevated levels in the ashed humus of almost all elements examined. There is only minimal response in pge and Au to the mineralization from any of the fractions of the soil; whereas the <2 μm fraction of the B-horizon soil reflects the mineralization by elevated levels of As, Sb, Se, Cr, Co, Ni, Cu, Pb and Zn. Only hmc from the tills show elevated pge, Au and variable enhancement in As, Sb, Se and the base metals. The < 2 μm portion of the tills tends to be highest in As, Se, Cr and the base metals.This ongoing study shows that surficial materials and vegetation are effective in identifying areas of concealed pge mineralization. Various pathfinder elements, primarily Cu and Ni, but perhaps also As, Se, Sb and the other base metals, in the < 2 μm B-horizon soils and tills, may be informative in a preliminary evaluation of the pge potential of an area, prior to undertaking the more expensive precious-metal analyses. Humus and vegetation both appear extremely effective, and most cost efficient, and heavy-mineral concentrates (hmc) appear effective, for identifying areas with pge potential, whereas hmc from tills appear most effective for zeroing in on the site of the pge mineralization.  相似文献   

The magnetospheric disturbance ring current as a source for probing the deep earth electrical conductivity     

Wallace H. Campbell 《Pure and Applied Geophysics》1990,134(4):541-557

Two current rings have been observed in the equatorial plane of the earth at times of high geomagnetic activity. An eastward current exists between about 2 and 3.5 earth radii (Re) distant, and a larger, more variable companion current exists between about 4 and 9 Re. These current regions are loaded during geomagnetic substorms. They decay, almost exponentially, after the cessation of the particle influx that attends the solar wind disturbance. This review focuses upon characteristics needed for intelligent use of the ring current as a source for induction probing of the earth's mantle. Considerable difficulties are found with the assumption thatDst is a ring-current index.  相似文献   

Old Fields: Photography,Glamour, and Fantasy Landscape          下载免费PDF全文

Craig Campbell 《Geographical review》2016,106(2):e24-e27

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Riverine dominance of a nearshore marine demersal food web: evidence from stable isotope and C/N ratio analysis     

AM de Lecea  AJ Smit  ST Fennessy 《African Journal of Marine Science》2016,38(1):S181-S192

The Thukela Bank, KwaZulu-Natal, supports a diverse ecosystem and South Africa’s only prawn fishery. Oceanographic studies suggest riverine input is not important for the biology of this system, whereas biological studies suggest the contrary, with prawn catches increasing with increased fluvial run-off. The aim of this study was to determine (i) the importance of riverine and marine organic matter for the Thukela Bank food web; and (ii) whether there are seasonal changes in the Thukela River stable isotope values, and, if so, whether these are reflected in the isotope values of demersal organisms. Estuarine organic matter, sediments and demersal organisms were collected from several sites across the bank in the wet and dry seasons of 2008, 2009 and 2010. Marine particulate organic matter was also collected in 2010 and analysed for δ13C and δ15N, as well as C/N ratios. There were strong seasonal changes in isotopic values of organic matter and fauna, especially faunal δ13C. There was an apparent time-lag in organisms assimilating riverine organic matter isotopic values, with the isotopic signature of demersal organisms reflecting that of riverine organic matter from the previous season, which is likely the result of tissue turnover time. In 2010, Thukela Bank sediment organic matter was of riverine origin and this maintained the demersal food web. We conclude that Thukela River organic matter is an important input to the food web of the Thukela Bank, indicating that any future damming of the catchment area could have serious consequences for this ecosystem.  相似文献   

Visit to the mineral department,British museum (natural history): February 26th, 1927     

W. Campbell Smith 《Proceedings of the Geologists' Association. Geologists' Association》1927,38(4):561

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