Regional estimation of base recharge to ground water using water balance and a base-flow index   总被引：4，自引：0，他引：4  

Szilagyi J  Harvey FE  Ayers JF 《Ground water》2003,41(4):504-513

Naturally occurring long-term mean annual base recharge to ground water in Nebraska was estimated with the help of a water-balance approach and an objective automated technique for base-flow separation involving minimal parameter-optimization requirements. Base recharge is equal to total recharge minus the amount of evapotranspiration coming directly from ground water. The estimation of evapotranspiration in the water-balance equation avoids the need to specify a contributing drainage area for ground water, which in certain cases may be considerably different from the drainage area for surface runoff. Evapotranspiration was calculated by the WREVAP model at the Solar and Meteorological Surface Observation Network (SAMSON) sites. Long-term mean annual base recharge was derived by determining the product of estimated long-term mean annual runoff (the difference between precipitation and evapotranspiration) and the base-flow index (BFI). The BFI was calculated from discharge data obtained from the U.S. Geological Survey's gauging stations in Nebraska. Mapping was achieved by using geographic information systems (GIS) and geostatistics. This approach is best suited for regional-scale applications. It does not require complex hydrogeologic modeling nor detailed knowledge of soil characteristics, vegetation cover, or land-use practices. Long-term mean annual base recharge rates in excess of 110 mm/year resulted in the extreme eastern part of Nebraska. The western portion of the state expressed rates of only 15 to 20 mm annually, while the Sandhills region of north-central Nebraska was estimated to receive twice as much base recharge (40 to 50 mm/year) as areas south of it.  相似文献   

K.M. Hiscock,M.O. Rivett,R.M. Davison (eds): Sustainable groundwater development     

Leonard?F.?KonikowEmail author 《Hydrogeology Journal》2003,11(5):609-610

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Mesoscale analyses of West African summer climate: focus on wave disturbances     

Leonard M. Druyan  Matthew Fulakeza  Patrick Lonergan 《Climate Dynamics》2006,27(5):459-481

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Relative stress variations as determined by b-values from earthquakes in circum-pacific subduction zones     

Jerry A. Carter  Eduard Berg 《Tectonophysics》1981,76(3-4)

Assuming a relation of “b” to stress state, the possibility of globe-wide stress variation and transmission was investigated. The NOAA earthquake data file served to determine the temporal change in “b” of log N = a − bM from 1963 to 1975.Periods of six to eight years are observed in the b-values (stress pattern) for most circum-Pacific areas (South America, Tonga, Kermadec, New Hebrides, Kamchatka and Eastern Aleutians).In the Kurils, fore- and aftershock sequences of large earthquakes seem to mask any characteristic global pattern that might exist. These sequences exhibit low b-values (high stress) through the time of foreshocks and early stages of aftershocks, followed by rapid increase in b-values (decrease in stress).Use of a worldwide earthquake data file clearly yields less resolution of the temporal “b” variation than the use of local network studies published by other authors.Incidental to the study, 1124 earthquakes of the NOAA data file yield the M_s − m_b relations: M_s = 1.16m_b − 0.835 for 4.5 m_b 6 and: log₁₀M_s = 0.1432m_b − 0.0629 form_b > 6 with correlative coefficients of 0.994 and 0.992 respectively.  相似文献   

Kepone®: Toxicity and bioaccumulation in blue crabs     

Steven C. Schimmel  James M. Patrick  Linda F. Faas  Jerry L. Oglesby  Alfred J. Wilson 《Estuaries and Coasts》1979,2(1):9-15

Two long-term studies were conducted to determine toxicity, uptake and depuration of Kepone in blue crabs (Callinectes sapidus). In the first, Kepone was administered to crabs in seawater (0.03 or 0.3 μg Kepone/I) or food (eastern oyster,Crassostrea virginica, containing 0.25 μg/g Kepone). Uptake of Kepone in 28 days was primarily through the contaminated oysters. When these crabs were held in Kepone-free seawater and fed Kepone-free oysters for 28 days, no loss of the insecticide was evident. There were adverse effects on molting and survival in crabs fed oysters that contained 0.25 μg/g Kepone. A second study was conducted to determine: (1) the depuration of Kepone over a 90-day period in blue crabs fed oysters from the James River, Virginia (containing 0.15 μg/g Kepone); and (2) the effects of Kepone on molting and survival of blue crabs fed James River oysters or laboratory-contaminated oysters that contained 0.15 or 1.9 μg/g Kepone. Crabs fed Kepone-contaminated oysters followed by a diet of Kepone-free oysters for 90 days had detectable concentrations of the insecticide in tissues. Also, blue crabs that ate oysters containing Kepone in concentrations similar to those found in oysters from the James River, died or molted less frequently than crabs fed Kepone-free oysters meats.  相似文献   

Simulated Effects of Irrigation on Salinity in the Arkansas River Valley in Colorado     

Karin Goff  Michael E. Lewis  Mark A. Person  Leonard F. Konikowd 《Ground water》1998,36(1):76-86

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Evaluation of cold-water carbonates as a possible paleoclimatic indicator     

Jay E. Leonard  Barry Cameron  Orrin H. Pilkey  Gerald M. Friedman 《Sedimentary Geology》1981,28(1):1-28

The common belief currently shared by many geoscientists concerning the climatic interpretation of limestones is that a warm-water environment is essential. This concept is not necessarily true because the rate and extent of terrigenous sediment dilution, rather than water temperature, is the primary factor determining whether or not a limestone forms at nearshore or continental shelf depths. Because carbonate productivity is lowest in cold climates, however, CaCO₃ abundance and the thickness of carbonate accumulations tend to be least at high latitudes. In this regard present-day continental shelves and beaches offer a poor model for comparing cold-water and warm-water carbonates because of the generally emergent continental tectonic framework, recent eustatic sea-level changes, and the presence of ice caps at the modern poles.Typically, the influence of climate on non-reef continental shelf and beach environments cannot be clearly distinguished by the presence or absence of major taxonomic groups. Faunal diversity and equitability are more sensitive in this regard. The absence of shelf-depth inorganic carbonate precipitates, micrite envelopes, and peloids may also point to the cold-water origin of a rock. Skeletal mineralogy and oxygen isotopes of certain unrecrystallized carbonates may be good paleoclimatic indicators; however, trace elements and physical-textural attributes of the carbonate fraction are probably temperature insensitive.Previous studies of high-latitude continental shelves have concentrated merely on the abundance of calcareous material and there is seemingly a disproportionate amount of information with respect to low-latitude carbonate studies. Further research on cold-water carbonates may open up new avenues for alternative paleoenvironmental and paleoclimatic interpretations.  相似文献   

Organic versus inorganic trace metal complexes in sulfidic marine waters—some speculative calculations based on available stability constants     

Leonard Robert Gardner 《Geochimica et cosmochimica acta》1974,38(8):1297-1302

A theoretical model has been developed in order to test the hypothesis that simple organic acids are the chief agents of trace metal solubility in H₂S-rich marine waters. The model utilizes stability constant given by Sillen and Martell (1964, 1971) and assumes that the free cation activity of each metal is controlled by simple solubility products. Typical values of pH, pS and Eh are employed in the calculations. The results indicate that free amino acids and hydrocarboxylic acids probably are not effective but that bisulfide and polysulfide complexes may be the chief agents of trace metal solubility. To the extent that it is present, the effect of dissolved organic matter on trace metal solubility probably resides in highly polymerized substances (e.g. humic acids).  相似文献   

Seven Asteroids Studied from Modra Observatory in the Course of Binary Asteroid Photometric Campaign     

Adrián Galád  Petr Pravec  Štefan Gajdoš  Leonard Kornoš  Jozef Világi 《Earth, Moon, and Planets》2007,101(1-2):17-25

We report lightcurves for five asteroids from the inner main belt—(1703) Barry, (2590) Mourão, (4022) Nonna, (5171) Augustesen, (23031) 1999 XX₇—and for two near-Earth asteroids—(100004) 1983 VA, (144922) 2005 CK₃₈—obtained at Modra Observatory as a part of binary asteroid photometric campaign. Estimated synodic rotational periods and amplitudes of their composite lightcurves were as follows: 107.1 ± 0.5 h, 0.5 mag for (1703) Barry; 15.59 ± 0.01 h, 0.49 mag for (2590) Mourão; 2.5877 ± 0.0005 h, 0.08 mag for (4022) Nonna; 474 ± 10 h, 0.8 mag for (5171) Augustesen; 3.075 ± 0.001 h, 0.43 mag for (23031) 1999 XX₇; 3.1643 ± 0.0009 h, 0.11 mag for (100004) 1983 VA; 4.7894 ± 0.0005 h, 0.27 mag for (144922) 2005 CK₃₈. The slow rotator (5171) Augustesen and possibly also (1703) Barry appear to be tumblers, though their precession periods can not be estimated from the available data.  相似文献   

Comments on the misuse of SPMDs in recent articles by Springman et al. (2008a,b) and Short et al. (2008)     

Paul D. Boehm  David S. Page  Jerry M. Neff 《Marine environmental research》2009,67(4-5):262-267

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