Effects of Urban Storm-Runoff Control on Ground-Water Recharge in Nassau County, New York   总被引：1，自引：0，他引：1  

Henry F. H. Ku  Nathan W. Hagelin  Herbert T. Buxton 《Ground water》1992,30(4):507-514

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Holocene sea-level changes in Palau,West Caroline Islands     

William H. Easton  Teh-Lung Ku 《Quaternary Research》1980,14(2):199-209

¹⁴C ages supplemented by ${}^{230}\text{Th}{}^{234}\text{U}$ determinations have been obtained for calcareous deposits on Koror, Babelthuap, Auluptagel, and Adorius Islands in the Palau Group, West Caroline Islands. Test borings for a bridge between Koror and Babelthuap reveal shoreface terraces consisting largely of bioclastic sand, but resembling fringing reefs. The base of the shoreface terraces dates to between 7000 and 8000 ¹⁴C yr B.P. and the upper surfaces are slightly younger than 4000 yr B.P. Spacing of the subsurface isochrons indicates that the rate of sedimentation increased up-section on Koror terrace and decreased up-section on Babelthuap terrace. The average rate of deposition in the terraces was 0.5 cm/yr. Isochrons in the Babelthuap shoreface terrace are 7 m higher than those in the Koror terrace. If deposition was sufficient to keep the surfaces of the terraces at low tide level, then the Babelthuap side was essentially stable and the Koror side was uplifted between about 8000 and 6300 yr ago, and then subsided until 4000 yr ago; since then there has been about 2 m of uplift. “Top hat” microatolls on Koror terrace indicate that relative sea level has dropped about 30 cm in the past 75 yr. In the absence of good evidence for changes of level in water ponded in a moat, it is likely that the microatolls indicate uplift of the terrace. On the other hand, if tectonic activity was minimal, then differences in the two terraces are due to differences in sedimentation with the Koror side of the channel being substantially subtidal between about 7000 and 5000 yr B.P. Taking the composite eustatic sea-level curve of Hawaii and elsewhere as a reference standard, it is deduced that Auluptagel Island has risen 0.8 m in the last 2900 yr, and Adorius Island has risen approximately 8 m in the last 5000–6000 yr.  相似文献   

Volles Gewicht einer im Refraktionsmilieu gemessenen Grösse (Teil II)     

Karel Kučera  Rezensent J. Kašpar 《Studia Geophysica et Geodaetica》1971,15(3-4):263-274

Ohne Zusammenfassung  相似文献   

Radium-226 measurements from three Geosecs intercalibration stations     

Y. Chung  H. Craig  T.L. Ku  J. Goddard  W.S. Broecker 《Earth and Planetary Science Letters》1974,23(1):116-124

This paper presents the results of²²⁶Ra intercalibration measurements made by three groups of investigators (LDGO, USC and SIO) on the seawater samples collected in profile at three Geosecs intercalibration stations. A common radium standard prepared from an NBS bulk standard for the Geosecs program has been adopted by all groups. At Geosecs-I station in the Northeast Pacific, the new²²⁶Ra results obtained from reoccupation of the station show that the agreement of the three groups has been significantly improved over the initial comparison made in 1970.At Geosecs-II in the Northwest Atlantic, the initial comparison of the²²⁶Ra profiles showed that the USC data were systematically higher than the SIO data by 1 radium unit of 10^?14 g/kg. This corresponds to a relative difference of 20% due to the very low radium content of Atlantic waters. The new results obtained from reoccupation of the station show that both the USC and SIO data are consistent with their previous data. Thus, a systematic difference of 1 radium unit still exists. However, the new LDGO profile falls in between those of USC and SIO, lying closer to the SIO profile.At Geosecs-III station in the Southwest Pacific, the²²⁶Ra measurements show that the LDGO data are systematically higher than the SIO data by about 10% above 3.4 km depth. Below this depth, both sets of data agree and show a sharp decrease in radium concentration. This radium discontinuity corresponds to the benthic front which is a density discontinuity separating the Deep and Bottom Water in the South Pacific.  相似文献   

Barium in the Antarctic Ocean and implications regarding the marine geochemistry of Ba and²²⁶Ra     

Y.H. Li  T.L. Ku  G.G. Mathieu  K. Wolgemuth 《Earth and Planetary Science Letters》1973,19(3):352-358

Ba distribution in the ocean correlates linearly with that of ²²⁶Ra, reflecting little fractionation of the two elements in their uptake by marine organisms. The weight ratio of ²²⁶Ra/Ba is estimated to be (0.714 ± 0.08) × 10^?8. A wide range of Ba/Si and Ra/Si values is noted in siliceous plankton collected from different oceans. This corraborates with the observations that, although silica co-varies with Ba and²²⁶Ra, the Ba/Si and²²⁶Ra/Si ratios in seawater vary from one area to another. Sediment pore water contains higher Ba concentrations than the overlying seawater. The resulting diffusive flux of Ba through the sediment-sea interface is estimated to be no more than 20% of the river input. The apparent oversaturation of dissolved Ba in pore fluids with respect to barite supports the idea that complexing of Ba with organic ligands may be important. Box model calculations show that: (1) on a per unit area basis, ²²⁶Ra flux from the continental shelf sediments is higher than that from the deep sea floor; (2) in the deep ocean, the magnitude of diffusive input of ²²⁶Ra from sediments is about equal to the loss due to radioactive decay.  相似文献   

Эффективность структурных весов     

Karel Kučerra 《Studia Geophysica et Geodaetica》1965,9(1):23-34

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NUMERICAL SIMULATION OF A MESOSCALE CONVECTIVE SYSTEM (MCS) DURING THE FIRST RAINY SEASON OVER SOUTH CHINA^*          下载免费PDF全文

MENG Weiguang  WANG Anyu  LI Jiangnan  FONG Soikun  KU Chimeng 《Acta Meteorologica Sinica》2003,17(1):79-92

Based on the NCEP/NCAR reanalysis data and observations collected during the SCSMEX,a mesoscale convective system (MCS) occurring over South China during 23-24 May 1998 has been studied with a numerical simulation using the Fifth Generation Penn-State/NCAR Mesoseale Modeling System (MMS).The successful simulations present us some interesting findings.The simulated MCS was a kind of meso-β scale system with a life cycle of about 11 hours.It generated within a small vortex along a cold front shear line.The MCS was characterized by severe convection.The simulated maximum vertical velocity was greater than 90 cm s^-1,and the maximum divergence at about 400 hPa.The rainfall rate of MCS exceeded 20 mm h^-1.To the right of the simulated MCS,a mesoscale low-level jet (mLLJ) was found.A strong southwesterly current could also be seen to the right of MCS above the mLLJ.This strong southwesterly current might extend up to 400 hPa.A column of cyclonic vorticity extended through most part of the MCS in the vertical direction.Additionally,the simulated MCS was compared favorably with the observational data in terms of location,precipitation intensity and evolution.  相似文献   

Stress modeling of tectonic blocks at Cape Kamchatka, Russia using principal stress proxies from high-resolution SAR: new evidence for the Komandorskiy Block     

Sarah B.Z. McElfresh  William Harbert  Cheng-Yu Ku  Jean-Shang Lin 《Tectonophysics》2002,354(3-4)

A new data set of 851 lineaments mapped from European Remote Sensing satellites 1 and 2 full resolution Synthetic Aperture Radar (SAR) data are interpreted as geological proxies for stresses resulting from plate and block collision near the Cape Kamchatka region of the Kamchatka Peninsula using a Geographical Information Systems-based analysis. Numerical Manifold Method (NMM) analysis is used to model the stress field within the Cape Kamchatka region resulting from the collision of lithospheric plates and blocks. Results of our NMM model, using different plate motion and plate configuration in the region, are compared with orientation data for the mapped set of lineaments. These data suggest that the lineaments observed in SAR cannot be fully explained by a simple two-plate model in this in the Cape Kamchatka region. As an alternative, we propose that the data can be explained by the existence of the previously proposed Komandorskiy Block. Recent Global Positioning Satellite measurements in the Aleutian Islands support our lineament-derived model and show that the near Islands/Komandorskiy Island block of the extreme western Aleutians is moving independently of the North American Plate.  相似文献   

Hydrologic variation during the last 170,000 years in the southern hemisphere tropics of South America   总被引：1，自引：0，他引：1  

Sherilyn C Fritz  Paul A Baker  Tim K Lowenstein  Catherine A Rigsby  Pedro M Tapia  Teh-Lung Ku 《Quaternary Research》2004,61(1):95-104

Despite the hypothesized importance of the tropics in the global climate system, few tropical paleoclimatic records extend to periods earlier than the last glacial maximum (LGM), about 20,000 years before present. We present a well-dated 170,000-year time series of hydrologic variation from the southern hemisphere tropics of South America that extends from modern times through most of the penultimate glacial period. Alternating mud and salt units in a core from Salar de Uyuni, Bolivia reflect alternations between wet and dry periods. The most striking feature of the sequence is that the duration of paleolakes increased in the late Quaternary. This change may reflect increased precipitation, geomorphic or tectonic processes that affected basin hydrology, or some combination of both. The dominance of salt between 170,000 and 140,000 yr ago indicates that much of the penultimate glacial period was dry, in contrast to wet conditions in the LGM. Our analyses also suggest that the relative influence of insolation forcing on regional moisture budgets may have been stronger during the past 50,000 years than in earlier times.  相似文献   

Incorporation of Be isotopes and other trace metals into marine ferromanganese deposits     

Masashi Kusakabe  Teh-Lung Ku 《Geochimica et cosmochimica acta》1984,48(11):2187-2193

Two-to threefold inward increase of ¹⁰Be, ⁹Be, Cu and Ni have been found in surface layers of marine ferromanganese deposits. We interpret this phenomenon as reflecting the manner in which the Be isotopes and probably other trace metals (e.g. Cu and Ni) are incorporated. On reaching the sea floor exchangeable Be is released from its carrier phase to the pore water of the ferromanganese deposits, diffuses inward and gets fixed into the deposits. The fixation process may be related to the mineralogical reorganizations suggested by previous studies. We have modeled this concept and applied it to a Mn crust on which detailed analyses of Cu, Ni and natural decay-series nuclides, as well as Be isotopes are made. Post-depositional fixation of Th isotopes may also occur. The redistributions of Be and Th isotopes are confined to regions very close to the surface of the deposits. For all practical purposes, they will not affect growth rate determinations conventionally done using these isotopes. The “linearly” extrapolated ${}^{10}\text{Be}{}^9\text{Be}$ ratio to the surface from deep layers of a Mn deposit does not necessarily represent that ratio in sea water.  相似文献