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Paleocurrent of the tidal sand body in Subei coastal plain

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Chinese Science Bulletin 1998年第12期43卷 1045-1047页

作者： Zhang Jiaqiang Li Congxian Cong Youzi Tongji Univ Lab Marine Geol Shanghai 200092 Peoples R China State Ocean Adm Inst Oceanog 1 Qingdao 266003 Peoples R China

Based on analysis of magnetic febric and magnetic relict, the paleocurrents recorded in drilling cores in Subei coastal plain.are bidirectional. NE_SW in the northern core and NW_SE in the southern core. The paleocurrent pattern in the area is similar to that of the tidal current system in the South Yellow Sea. So it is inferred that the convergent_divergent tidal current system existed during stage of sand body formation, and they should be radial in plane.

关键词： magnetic fabric paleocurrent tidal sand body Subei coastal plain.

A study of ^(36)Cl age in Quaternary groundwater of Hebei plain.China

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Science China(Technological Sciences) 2001年第S1期44卷 11-15页

作者：周炼刘存富姜山高山 Faculty of Geosciences China University of Geoscience Wuhan China Chinese Academy of Atomic Energy China

Chlorine-36 has various advantages as a dating tool for old groundwater. In this paper, 36CI of Quaternary groundwater in the Hebei plain.of North China has been measured using accelerator mass spectrometry (AMS). Ages calculated from the 36CI/CI ratio show that ion filtration, which is responsible for the CI- concentration increasing with depth and along flow paths in Hebei plain.groundwater. It is concluded that 36CI age of the groundwater in the 3rd Group of the Quaternary (Q2) in the Cangzhou area is 250ka, and that of the 4th Group(Q1) is 300ka.

关键词： 36Cl accelerator mass spectrometer (AMS) Hebei plain.

Water, heat fluxes and water use efficiency measurement and modeling above a farmland in the North China plain

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Science China Earth Sciences 2005年第Z1期48卷 207-217页

作者： QIN Zhong, YU Qiang, XU Shouhua, HU Bingmin, SUN Xiaomin, LIU Enmin, WANG Jishun, YU Guirui & ZHU Zhilin Ecology academy, College of Life Science, Zhejiang University, Hangzhou 310029,China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China College of Science, Zhejiang University, Hangzhou 310029, China Ecology academy College of Life Science Zhejiang University Hangzhou 310029China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Ecology academy College of Life Science Zhejiang University Hangzhou 310029China College of Science Zhejiang University Hangzhou 310029 China

Net radiation (Rn), water vapor flux (LE), sensible heat flux (Hs) and soil heat flux (G)were measured above a summer maize field with the eddy-covariance technique, simulation and analysis of water, heat fluxes and crop water use efficiency were made with the RZ-SHAW model at the same time in this study. The results revealed significant diurnal and seasonal variability of water vapor flux for summer maize. Most part of Rn was consumed by the evapotranspiration of the summer maize. The proportion of water vapor flux to net radiation ((LE/Rn) increased with the crop development and peaked around milk-filling stage with a value of 60%, a slightly lower than that obtained by the RZ-SHAW model. Daily evapotranspiration estimated by the model agreed with the results measured with the eddy-covariance technique, indices of agreement (IA) for hourly water vapor fluxes simulated and measured were above 0.75, root mean square errors (RMSE) were no more than 1.0. Diurnal patterns of Hs showed the shape of inverted "U" shifted to the forenoon with a maximum value around 11:30 (Beijing time), while LE exhibited an inverted "V" with a maximum value at around 13:00, about an hour later than Hs. Diurnal change of CO2showed an asymmetrical "V" curve and its maximal rates occurred at about 11:30. Variations of water use efficiency during the phonological stages of the summer maize showed a rapid increase with the photosynthetic photon flux density (PPFD) after sunrise, a state of equilibrium around 10:00 followed a decrease. Maximum values of water use efficiency were 24.3, and its average value ranged from 7.6 to 10.3 g kg-1.

关键词： water vapor flux, CO2 flux, water use efficiency, RZ-SHAW model, maize, North China plain.