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1.
首次利用三分量数字地震仪在西藏羊易地热田区记录到近震转换波,并用于研究深部构造取得了结果.查明了测区基底构造的基本特征,发现热田区发育了NNW和NEE向一系列断裂,其延深可达6-9km,不同方向断裂的交汇对热田有控制作用.在热田内基底形成一近NS向断块状局部隆起.经过热田深部传播的近震转换波的频谱主频和振幅比均有明显降低,这些特征显示热田深部可能有局部熔融的岩脉沿深断裂活动.表明在热田区的微震观测中同时利用近震转换震相研究深部构造是可行的. 相似文献
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研究了奇村热水井水汞异常与山西境内地震的关系，发现奇村热水井水汞异常与山西境内Ｍ＞４．０地震有较好的对应关系。说明水汞是奇村热水井的映震灵敏的观测项目 相似文献
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阐述了热田区热水开采对怀来4井水氡、气氡引起的阶段性变化,针对开采引起的干扰情况,采取了相应的抗干扰措施,保证了地下流体观测资料的可靠性. 相似文献
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通过对山西忻州奇村水化站水汞观测水样与空白样测值曲线所含信息的研究,论述了两者产生同步现象的原因及其动态特征,进而提出排除水汞干扰、识别水汞异常的方法。 相似文献
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本文根据1985-1986年在福建省穿过漳州热田地区完成的一条NNE向地震折射剖面资料,采用一维与二维射线追踪和理论地震图拟合、反演等方法,获得了该地区比较详细的地壳与上地幔顶部结构及速度分布图像.结果表明:漳州热田地区正好位于一个地壳厚度突变带上,从漳州市往南向海岸方向地壳上隆,厚度只有29.5km,往北迅速加大到32.0 km左右;在这个突变带上地壳内所有速度界面均发生扭曲甚至错动,它可能是一个断裂带;地壳中部有一个横向延伸有限的低速区,其最低速度小于5.80km/s,顶部深度大于10.2km,这个低速区正好位于漳州市下方的地壳突变带上.作者推断它很可能就是漳州热田的壳内热源体,并可能是一个部分熔融体. 相似文献
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分析了河北省怀来县后郝窑热田区的构造特征和怀来4井井孔成孔条件，研究了怀来4井水汞异常与地震的关系，分析该井的映震灵敏性，认为有以下几个方面的原因：①该井处于热田区活动断裂上；②含水层母岩为糜棱岩化片麻岩及泥质物塑状体，怀来4井水汞映震异常与其所处独特的地质构造、成孔条件及汞的物理化学性质的有机结合密不可分，因而有较好的映震效果。 相似文献
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利用1979年1月至2016年12月ERA-interim月平均再分析资料和CAMP全球月降水资料,分析夏季（6—8月）南亚高压下方500 hPa到100 hPa暖中心的时空分布,从三维结构来揭示夏季南亚高压暖心特征.回归分析进一步探讨青藏高原上空暖中心对全球大气环流产生的可能影响.结果表明：南亚高压在150 hPa达到最强,这一层也是异常冷暖中心分界面,150 hPa以下有一强大异常暖中心,异常暖中心位于300 hPa附近,150 hPa以上为异常冷中心,中心位置位于70 hPa附近.异常暖中心从500 hPa向上逐渐向西向北倾斜,异常暖中心面积200 hPa达最大,150 hPa异常暖中心消失,100 hPa以上转变为异常冷中心.500~200 hPa异常暖中心表现出不断增暖的长期趋势（1979—2016）,100 hPa异常冷中心则表现出不断变冷的长期趋势（1979—2016）.去掉长期趋势的时间序列表现出明显的"准两年振荡"特征,异常暖中心位置在纬向上较稳定,在经向上表现出年际的"东西振荡".300 hPa异常暖中心是整个南亚高压的关键层.300 hPa异常暖中心对全球其他变量场进行回归分析.高度回归场表明,青藏高原上空异常暖中心在北半球中高纬度高度场上激发出3波的行星波,波特征在对流层中上层表现明显,波振幅随高度增高不断加强,在对流层中下层逐渐减弱并消失.纬向风回归场在对流层中上层表现出横跨南北半球的波列,这个波列在200 hPa振幅最大.经向风回归场在北半球中纬度（30°N—60°N）表现出7波型,说明南北能量交换频繁.降水回归场表明,东亚地区长江中下游至日本降水偏少,而其南北两侧降水偏多. 相似文献
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《Advances in water resources》1998,21(5):363-373
A two-dimensional (2D) unsteady simulation model is applied to the problem of a submerged warm water discharge into a stratified lake or reservoir with an ice cover. Numerical simulations and analyses are conducted to gain insight into large-scale convective recirculation and flow processes in a cold waterbody induced by a buoyant jet. Jet behaviors under various discharge temperatures are captured by directly modeling flow and thermal fields. Flow structures and processes are described by the simulated spatial and temporal distributions of velocity and temperature in various regions: deflection, recirculation, attachment, and impingement. Some peculiar hydrothermal and dynamic features, e.g. reversal of buoyancy due to the dilution of a warm jet by entraining cold ambient water, are identified and examined. Simulation results show that buoyancy is the most important factor controlling jet behavior and mixing processes. The inflow boundary is treated as a liquid wall from which the jet is offset. Similarity and difference in effects of boundaries perpendicular and parallel to flow, and of buoyancy on jet attachment and impingement, are discussed. Symmetric flow configuration is used to de-emphasize the Coanda effect caused by offset. 相似文献
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Annual and interannual variations of the Western Pacific Warm Pool volume and sources of warm water revealed by Argo data 总被引：1，自引：0，他引：1
Based on gridded Argo profile data from January 2004 to December 2010, together with the P-vector inverse method, the three-dimensional structure, annual and inter-annual variations in volume of the Western Pacific Warm Pool(WPWP) are studied. The variations of latitudinal and longitudinal warm water flowing into and out of the WPWP and the probable mechanism of warm water maintenance are also discussed. From the surface to the bottom, climatic WPWP tilts southward and its area decreases. The maximum depth could extend to 120 m, such that its volume could attain 1.86×1015 m3. Annual variation of the WPWP volume shows two obvious peaks that occur in June and October, whereas its inter-annual variations are related to ENSO events. Based on a climatic perspective, the warm water flowing latitudinally into the pool is about 52 Sv, which is mainly through upper layers and via the eastern boundary. Latitudinally, warm water flowing outward is about 49 Sv, and this is mainly through lower layers and via the western boundary. In contrast, along the latitude, warm water flowing into and out of the pool is about 28 Sv and 23 Sv, respectively. Annual and inter-annual variations of the net transportation of the warm water demonstrate that the WPWP mainly loses warm water in the west-east direction, whereas it receives warm water from the north-south direction. The annual variation of the volume of WPWP is highly related to the annual variation of the net warm water transportation, however, they are not closely related on inter-annual time scale. On the inter-annual time scale, influences of ENSO events on the net warm water transportation in the north-south direction are much more than that in the west-east direction. Although there are some limitations and simplifications when using the P-vector method, it could still help improve our understanding of the WPWP, especially regarding the sources of the warm water. 相似文献
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Variability in water-exchange time between Tokyo Bay and the Pacific Ocean during winter is investigated based on the results of intensive field observation from November 2000 to March 2001. Water-exchange time between Tokyo Bay and the Pacific Ocean during winter mainly depends on the strength of northerly monsoon, being about 16 days under the weak monsoon and about 12 days under the strong monsoon. Moreover, it becomes longer by about 1 day in spring tide and shorter in neap tide due to the coupling effect of estuarine circulation and vertical mixing. Water-exchange time also varies depending on the open-ocean condition. When the warm water mass approaches from the Pacific Ocean to the mouth of Tokyo Bay through the eastern channel of Sagami Bay, which connects Tokyo Bay and the Pacific Ocean, water-exchange time becomes longer by about 2 days because the warm water mass is blocked in the surface layer at the bay mouth. On the other hand, when the warm water mass approaches to the mouth of Tokyo Bay through the western channel of Sagami Bay, water-exchange time becomes shorter by about 1 day because the warm water mass intrudes into the middle or lower layers of Tokyo Bay. Such different behavior of warm water mass at the mouth of Tokyo Bay is due to the difference in density of approaching warm water masses, that is, the density of the warm water mass through the eastern channel is smaller than that of the warm water mass through the western channel of Sagami Bay.Responsible Editors: Yens Kappenberg 相似文献
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June K. Yeung James A. SmithGabriele Villarini Alexandros A. NtelekosMary Lynn Baeck Witold F. Krajewski 《Advances in water resources》2011,34(2):184-204
We examine the warm season (April-September) rainfall climatology of the northeastern US through analyses of high-resolution radar rainfall fields from the Hydro-NEXRAD system and regional climate model simulations using the weather research and forecasting (WRF) model. Analyses center on the 5-year period from 2003 to 2007 and the study area includes the New York-New Jersey metropolitan region covered by radar rainfall fields from the Fort Dix, NJ WSR-88D. The objective of this study is to develop and test tools for examining rainfall climatology, with a special focus on heavy rainfall. An additional emphasis is on rainfall climatology in regions of complex terrain, like the northeastern US, which is characterized by land-water boundaries, large heterogeneity in land use and cover, and mountainous terrain in the western portion of the region. We develop a 5-year record of warm season radar rainfall fields for the study region using the Hydro-NEXRAD system. We perform regional downscaling simulations for the 5-year study period using the WRF model. Radar rainfall fields are used to characterize the interannual, seasonal and diurnal variation of rainfall over the study region and to examine spatial heterogeneity of rainfall. Regional climate model simulations are characterized by a wet bias in the rainfall fields, with the largest bias in the high-elevation regions of the model domain. We show that model simulations capture broad features of the interannual, seasonal, and diurnal variation of rainfall. Model simulations do not capture spatial gradients in radar rainfall fields around the New York metropolitan region and land-water boundaries to the east. The model climatology of convective available potential energy (CAPE) is used to interpret the regional distribution of warm season rainfall and the seasonal and diurnal variability of rainfall. We use hydrologic and meteorological observations from July 2007 to examine the interactions of land surface processes and rainfall from a regional perspective. 相似文献
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Peter Petrusevics John Bye John Luick Carlos E.P. Teixeira 《Continental Shelf Research》2011,31(7-8):849-856
Historical and recent oceanographic cruise data, MODIS chlorophyll-a satellite data, and an analytical model are used to examine SST fronts in the entrance to Spencer Gulf, South Australia. The fronts (2–3 °C) due to the contrast between warm Spencer Gulf waters and cooler waters of the continental shelf are readily observable on satellite imagery. Three water masses: cool, fresh upwelled shelf water; warm, salty Great Australian Bight water; and very warm and salty Spencer Gulf bottom water occupy the area. In consequence a summer density minimum is formed at the entrance to Spencer Gulf. The analytical model predicts that this thermohaline structure sets up an ageostrophic circulation, which favours upwelling in the central portion of the entrance. This is confirmed by the satellite data which show an increased chlorophyll-a concentration in the vicinity of the upwelling. 相似文献
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Pierre L’Hégaret Léo Lacour Xavier Carton Guillaume Roullet Rémy Baraille Stéphanie Corréard 《Ocean Dynamics》2013,63(6):633-659
Trajectories and hydrological data from two Argo floats indicate that warm and salty water at 200–300-m depths was ejected from the coast of Oman, near Ras al Hamra, in spring 2008, 2011, and 2012. This warm and salty water, Persian Gulf Water (PGW), once ejected from the coast, recirculated cyclonically in the western Sea of Oman, but also flowed eastward along the Iranian and Pakistani coasts. There, it was expelled seaward by mesoscale eddies as shown by other float data. Seasonal maps of salinity were computed from all available Argo floats; they showed that, in spring, PGW is present in the middle and north of the Sea of Oman, contrary to fall, when the salinity maxima lie southeast of Ras al Hadd. The ejection of PGW from Ras al Hamra is related here to the influence of a mesoscale dipolar eddy which often appears near this cape in spring. The time-averaged and empirical orthogonal functions of altimetric maps over 11 years for this season confirm the frequent presence and the persistence of this feature. From surface currents and hydrology, deep currents were computed via thermal wind balance, and the associated shear and strain fields were obtained. This deformation field is intense near Ras al Hamra, with an offshore direction. This flow structure associated with the mesoscale dipole explains PGW ejection from the coast. This observation suggests that PGW distribution in the Northern Arabian Sea can be strongly influenced by seasonal mesoscale eddies. 相似文献
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During mid-May to early June 2016, a cold eddy and a warm eddy were captured on the continental slope of the northern South China Sea by the in situ measurements. A salty lens-shaped water mass in the subsurface layer existed in these two detected eddies, which indicated they had a Kuroshio water origin. The trajectories of the observed eddies from satellite altimeter data show that the cold eddy was generated in the central part of the Luzon Strait, while the warm eddy was formed southwest of Taiwan. The genesis of the cold eddy is related to a weak Kuroshio loop current, while that of the warm eddy is associated with a strong Kuroshio loop current. The warm eddy east of the Luzon Strait may trigger the Kuroshio from a leaping path to a looping path. During the evolution of these detected eddies, they had interactions with the Kuroshio and Luzon Gyre. Energy analysis from ocean reanalysis data showed that the baroclinic conversion between the cold eddy and the Kuroshio was stronger than that between the cold eddy and Luzon Gyre. During the eddy shedding stage, the warm eddy mainly acquired energy from the Kuroshio loop current through the baroclinic conversion. 相似文献
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J.F. Macqueen 《Advances in water resources》1978,1(3):169-174
Cooling water discharged from power stations in the U.K. is frequently released from an outlet in an estuary or the sea. The warm water forms a thermal plume which is slightly buoyant and which spreads horizontally over the water surface while mixing vertically downwards with the cooler ambient water. In this paper, the possibility of vortex pair production at the cooling water outlet is considered as a mechanism contributing to this spreading of the warm water.The motion of a vortex pair contained between two rigid plane boundaries is an idealization of the flow between the water surface and the sea bed. The resulting motion is calculated from potential theory and viscous effects are neglected. The problem of deciding what strength to assign the vortices is discussed and specific consideration of shear and buoyancy at the outlet is detailed. It is observed that bifurcation of the vortex pair is determined by the initial position of the vortices and is unlikely to occur in conditions relevant to U.K. power station discharges.It is calculated that, in the absence of turbulence, the motion of such vortex pairs would result in horizontal spreading of the warm water which is greater than that observed at site surveys. It is concluded that turbulence in the ambient receiving water is sufficient to destroy vortices produced by the discharge during the early stages of the plume development. 相似文献
20.
The use of mixing models and chemical geothermometers for estimating underground temperatures in geothermal systems 总被引：1，自引：0，他引：1
Application of various chemical geothermometers and mixing models indicate underground temperatures of 260°C, 280°C and 265°C in the Geysir, Hveravellir and Landmannalaugar geothermal fields in Iceland, respectively. Mixing of the hot water with cold water occurs in the upflow zones of all these geothermal systems. Linear relations between chloride, boron and δ18O constitute the main evidence for mixing, which is further substantiated by chloride, silica and sulphate relations in the Geysir and Hveravellir fields.A new carbonate-silica mixing model is proposed which is useful in distinguishing boiled and non-boiled geothermal waters. This model can also be used to estimate underground temperatures using data from warm springs. This model, as well as the chloride-enthalpy model and the Na-Li, and CO2-gas geothermometers, invariably yield similar results as the quartz geothermometer sometimes also does. By contrast, the Na-K and the Na-K-Ca geothermometers yield low values in the case of boiling hot springs, largely due to loss of potassium from solution in the upflow. The results of these geothermometers are unreliable for mixed waters due to leaching subsequent to mixing. 相似文献