Influence of open and sealed fractures on fluid flow and water saturation in sandstone cores using Magnetic Resonance Imaging     

S. Baraka-Lokmane  G. Teutsch  I. G. Main 《Geophysical Journal International》2001,147(2):263-271

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岩溶水动态,矿物饱和指数与水源地选择     

李振拴  左建平 《煤田地质与勘探》1996,24(2):31-34

在分析区域地下水动态特征的基础上，用化学热力学方法计算出每个钻孔岩溶水的碳酸盐岩矿物饱和指数，结合二者之间的关系，找到了富水分布规律。通过勘探证实，在碳酸盐岩分布区，供水水源地应选择在地下水动态变化不大、滞后期不长、碳酸盐岩矿物馆和指数βｃ＞１～βｄ＜１的灰岩浅埋区。  相似文献   

冬小麦水分利用效率及其环境影响因素分析   总被引：28，自引：0，他引：28  

李俊  于沪宁 《地理学报》1997,52(6):551-560

１９９６年４月～６月在华北平原采用波文比－能量平衡法测定冬小麦田蒸散和ＣＯ２通量，求取冬小麦瞬时水分利用效率。土壤湿度较低时，冬小麦瞬时水分利用效率呈Ｌ型或Ｕ型日变化，其变化范围在－０．０１９４～０．６４１４；日较差范围在０．１１３８～０．６３２１。瞬时水分利用效率早晨最高且变化迅速，白天较低且变化平缓。土壤湿度较高时，瞬时水分利用效率范围在－０．０１５７～０．１３８１；日较差范围在０．０６１６～０．１５３７，其日变化不明显。从冬小麦拔节期到灌浆期，水分利用效率白天平均值变化较大，其范围在０．０１１０～０．０５３２，日较差变化范围在０．０６１６～０．６３２１，二者均于５月中旬达到最高，之后在波动中呈下降趋势。冬小麦水分利用效率白天平均值和日较差的季节变化明显受土壤水分影响。冬小麦水分利用效率白天平均值与０ｃｍ～６０ｃｍ的有效土壤水分呈负相关，达到０．０５显著水平；与０ｃｍ～２０ｃｍ和０ｃｍ～１００ｃｍ土层土壤有效水分无明显相关关系。冬小麦瞬时水分利用效率与饱和差呈极显著负相关，达到０．０１显著水平。土壤湿度较低时二者呈幂相关关系；土壤湿度较高时二者呈线性相关，且相关系数比土壤湿度低时高。在低土壤含水量下，冬  相似文献   

Carbonate-related parameters of subsurface waters in the West Philippine, South China and Sulu Seas   总被引：3，自引：0，他引：3  

Chen-Tung Arthur Chen  Wei-Ping Hou  Toshitaka Gamo  Shu Lung Wang   《Marine Chemistry》2006,99(1-4):151

Like most other deep basins in Southeast Asia, the deep Sulu Sea (SS) basin is isolated from the neighboring seas by surrounding topography. While the near-surface circulation is mainly governed by the seasonally reversing monsoon winds, below the warm and fresh surface layer, the core of the incoming Subtropical Lower Water from the West Philippine Sea (WPS), by way of the South China Sea (SCS), can be seen, at a depth of around 200 m, to have a distinct salinity maximum. It lies well above the sill depth (420 m) in the Mindoro Strait and thus, its spreading is not hampered by topography. The deep circulation is forced by an inflow of upper North Pacific Intermediate Water (NPIW) from the SCS through the Mindoro Str. Below 1000 m, the physico-chemical properties are remarkably homogeneous. The higher temperature, but lower salinity, oxygen and nutrients, of the deep SS waters, compared to those of the SCS, is indicative of the intrusion of NPIW above the sill depth. The excess, anthropogenic CO₂ penetrates the entire water column, because of the over-spill of the excess CO₂-laden water from the SCS.It has been reported that the bottom of the SS is CaCO₃ rich, relative to the SCS. Previous investigators attribute this to the higher θ in the SS. Indeed, the aragonite does not become undersaturated in the SS until below 1400 m, compared to 600 m in both the WPS and SCS; and the calcite does not become undersaturated until below 3800 m in the SS, compared to 2500 m in the SCS and around 1600 m in the WPS. However, the temperature effect is relatively small. These large differences are, in fact, largely a result of higher CO₃²⁻ concentrations in the SS, relative to the WPS and SCS. The higher CO₃²⁻ concentration in the SS, in turn, is mainly caused by the smaller amounts of organic carbon decomposition.  相似文献   

Shadowband的数据处理方法     

李铜基  陈清莲  李林奇 《海洋技术学报》2002,21(3):31-34

Shadowband是由加拿大 Satlantic公司研制用于测量总辐照度和天空漫射辐照度的现场测量设备。 2 0 0 0年 10月 ,我们在黄海首次使用了该设备进行试验 ,取得了良好的效果。在简要介绍 Shadowband工作原理的基础上 ,概述了 Shadowband数据处理的基本方法 ,并提出现场测量的改进措施。  相似文献   

Estimation of the PAR irradiance ratio and its variability under clear-sky conditions at ieodo in the east china sea     

Do -Seong Byun  Yang -Ki Cho 《Ocean Science Journal》2006,41(4):235-244

Determining ‘photosynthetically active radiation’ (PAR) is a key part of calculating phytoplankton productivity in a biogeochemical model. We explore the daily and seasonal variability in the ratio of PAR irradiance to total irradiance that occurred at Ieodo Ocean Research Station (IORS) in the East China Sea under clear-sky conditions in 2004 using a simple radiative transfer model (RTM). Meteorological data observed at IORS and aerosol optical properties derived from Aerosol Robotic Network observations at Gosan are used for the RTM. Preliminary results suggest that the use of simple PA R irradianceratio values is appropriate in calculating phytoplankton productivity as follows: an average of 0.44 (±0.01) in January to an average of 0.48 (±0.01) in July, with average daily variabilities over these periods of about 0.016 (±0.008) and 0.025 (±0.008), respectively. The model experiments demonstrate that variations in the major controlling input parameters (i.e. solar zenith angle, precipitable water vapor and aerosol optical thickness) cause PAR irradiance ratio variation at daily and seasonal timescales. Further, increases (>0.012) in the PAR irradiance ratio just below the sea-surface are positively correlated with high solar zenith angles and strong wind stresses relative to those just above the sea-surface.  相似文献   

Analysis of Dynamic ECG in the 80 Meters Saturation -100 Meters Excursion Heliox Dive     

Gao Bingchun  Gong Zhiping  Huang Xiaoqin Head of the Medical Department  The No. Hospital of PLA  Shanghai Vice Head of the Medical Department  The No. Hospital of PLA  Shanghai Resident Physician  The No. Hospital of PLA  Shanghai 《中国海洋工程》1991,(3)

The study deals with the observation of the changes in the electrical activities of 8 healthy divers in the 80 msw saturation-100 msw excursion heliox dive by DCG. Results showed significant changes in the 24 h of average heart rate, the decrease of heart rate at saturation storage depth and decompression periods being 15.5% and 19.7% respectively. Fortuitous supraventricular premature beats appeared in 8 divers and ventricular premature beats in 5 divers during exposure. Transient ischemic ST-T changes in 6 divers occurred repeatedly during diving operations. The discussion puts up the view that the ST-T changes were due to the stress reaction of the body induced by the combined effect of such stress factors as hyperbaric pressure per se, high partial pressure of oxgen, noise and the closed restricted chamber environment.  相似文献   

南沙珊瑚礁对大气CO2含量上升的响应   总被引：1，自引：0，他引：1  

张远辉  陈立奇 《台湾海峡》2006,25(1):68-76

本文利用南沙海域的碳酸盐化学以及相关调查资料，分析了表层CaCO3饱和度的分布特征，通过碳酸盐的热力学计算模式，定量评估了未来大气CO2增加对表层CaCO3饱和度的潜在影响，利用CaCO3饱和度与珊瑚钙化速率的经验关系式，进一步预测了珊瑚礁对大气CO2上升可能产生的生物地球化学响应．初步结果显示，工业革命前至2100年，南沙海域的CaCO3饱和度将下降43％左右，从而将引起珊瑚礁的平均钙化速率减少33％．如果未来大气CO2浓度继续保持目前的上升趋势，南沙海域珊瑚礁可能会停止生长，甚至某些造礁生物面，临灭绝的危险．  相似文献   

两种盐藻光合作用特性的比较   总被引：2，自引：2，他引：2  

彭长连  林植芳  孙谷畴  施定基 《海洋与湖沼》1994,25(6):606-611

于1989年9－11月分别在中国科学院水生生物研究所和天津轻工部制盐研究所取得盐藻Dunaliellasp.HB558和Dunaliellasalina1009。这两个藻种的光合放氧-光强曲线，光系统Ⅰ、光系统Ⅱ活性-温度曲线及甘油产量的结果表明，其光合作用的光饱和点皆为220μmol／（m2·s），并可忍受40℃的温度；当温度为45℃时，D．sp．HB558的光合放氧明显受到抑制，光系统II活性下降，但对从D.salina1009则无影响;D.sp.HB558在10-40℃下的光合放氧速率及甘油产量都高于D.salina1009.培养这两种蕉的最适温度为30—35℃。  相似文献   

The temporal and spatial distribution of underwater quantum irradiation in a southern California kelp forest     

Thomas A. Dean 《Estuarine, Coastal and Shelf Science》1985,21(6):835-844

The weekly integrals of underwater photon flux density were measured for a two and a half year period in a southern California kelp forest. Photon flux densities were lowest from January to April and peaked in summer. On average, about 2% of the surface irradiation reached the bottom (depth of 13·2 m in an area without a kelp canopy). Photon flux densities under a canopy of giant kelp were reduced by 70% compared to a nearby site cleared of kelp. A significant portion of temporal variability in underwater photon flux density was explained by vertical sediment flux. Surface irradiation did not contribute significantly to the variance in weekly values of underwater irradiation.  相似文献