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1.
利用2004年4月至2006年4月采集于厦门沿岸地区的44个雨水样品,对降水中的氢、氧同位素组成及其影响因素进行了分析和研究,结果表明:(1)厦门沿岸地区大气降水中δ18O值为-10.30‰~-0.13‰,平均值为-3.67‰;δD值为-74.7‰~7.3‰,平均值为-20.5‰,均处于全球及国内降水中δ18O和δD值的变化范围内。(2)厦门沿岸地区大气降水中的δ18O和δD值受纬度效应影响。(3)厦门沿岸地区大气降水中δ18O和δD值的季节差异较大,季风气候及其导致的降雨量效应是影响该地区δ降水值季节变化的主要因素。(4)降水中的氘过剩值(d值)为1.21‰~17.10‰,平均值为8.87‰,小于世界大部分区域雨水中的d值,说明厦门沿岸地区的降水源区蒸发速率比较缓慢,降水云团主要来自海洋汽团。(5)厦门沿岸地区大气降水线为:δD=7.67δ18O+7.68(p0.0001,R2=0.9876),与全球及国内的降水线接近,说明雨滴在降落过程中存在一定的再蒸发过程,该特征在夏季较显著。  相似文献   

2.
南海与西太平洋海水的交换:氧、氦同位素证据   总被引:3,自引:0,他引:3  
研究了西太平洋海域(7°~26°N,122°~130°E)不同深度海水的氧、氦同位素组成和分布特征.结果表明,巴士海峡附近海域几个深度上δ18O等值线均向东弯曲,δ3He等值线也出现了类似的分布特征,可能反映了南海海水与黑潮水的混合作用.氧、氦同位素的研究结果为南海海水通过巴士海峡侵入了西太平洋提供了地球化学证据.  相似文献   

3.
厦门大气降水的氢氧同位素研究   总被引:15,自引:0,他引:15  
本文研究了厦门地区大气降水的氢、氧同位素组成,提出了大气降水线方程的δD=8.16δ^18O+10.68,并与全国及全球降水线进行比较,揭示了该降水线方程的特征。对全年氚过剩值(d)及降水线特征研究表明,厦门岛全年降不涞源较为单一,主要为海洋性气团。降水中δD与δ^18O的降水量效应明显,且该影响远远掩盖了温度效应。  相似文献   

4.
大洋和近岸水的氧同位素组成研究   总被引:2,自引:0,他引:2  
本文通过对大洋表层水的δ~(18)O值测试,论述了洋区δ~(18)O值分布的均匀性特征。天然降水的淡化作用,可以造成局部洋区瞬时的δ~(18)O值变化。长江冲淡水和南极冰融水的δ~(18)O值,提供了研究海水混合作用、海流运移方向以及水团性质的重要信息。大洋表层水的δ~(18)O值与盐度呈极好的正相关关系,这种关系是探讨大洋深层水来源问题的重要依据。  相似文献   

5.
在配备双路进样系统的稳定同位素质谱仪(Isotope Ratio Mass Spectrometry:IRMS)上采用气体平衡法测定微量水样的高精度氢氧稳定同位素组成,同时采用国际及国家水稳定同位素标样及实验室工作标准进行多次测试及校正,获得δD的外部精度为1.0‰-2.0‰,δ18O的外部精度好于0.1‰.利用该方法对2007年冬季北海附近表层海水、河口水等水体的δD、δ18O进行测定,结果显示,δD、δ18O组成可以区分不同的水体,δD与δ18O存在显著正相关关系,但其δD-δ18O相关关系与邻近地区大气降水有明显差异;同时δD、δ18O与盐度也存在很好的正相关关系.这些结果意味着δD-δ18O关系主要反映海水与河水的混合过程.结合现场观测的水文资料,发现δ18O与表面水温有中等相关性,意味着蒸发作用对水体的氧同位素组成也有一定的影响.这些关系可应用于海水对近岸水域影响的研究,以及利用δ18O-盐度方程重建古盐度.  相似文献   

6.
南海东北部海区1994年夏季海水氧同位素示踪物分析结果表明:氧同位素δ18O值的分布在一定程度上反映了本区环流的某些特征。δ18O值在垂向上表现出表层低正值,次表层达到最大值,然后随深度的增加逐渐降低的特点。δ18O值的断面分布与平面分布为东沙群岛附近流环的存在提供了同位素示踪物证据。此外,对δ18O值与盐度、温度的相互关系进行了初步讨论。  相似文献   

7.
南太平洋降水中MSA的纬度分布及其分解的气温敏感性   总被引:2,自引:0,他引:2  
对“中国第12次南极考察队”南太平洋航线上降水样品中MSA的分析指出,MSA含量由赤道海域向高纬海域呈递增趋势,其中在15°S附近海域以及60°~65°S之间表现为突然上升,正好对应上升洋流区.MSA/nssSO42-比率与δD密切相关,显示MSA向nssSO42-的转化速率敏感地依赖于温度变化.  相似文献   

8.
大西洋海表温度异常与中国东北地区夏季降水的关系   总被引:7,自引:0,他引:7  
白人海 《海洋通报》2001,20(1):23-29
利用1950~1992年全球海温月平均(2°×2°)和NCAR/NCEP提供的1950~1997年全球500hPa月平均高度场(2.5°×2.5°)资料,分析了大西洋海表温度异常的特征及其与中国东北地区夏季降水的关系。结果指出北大西洋冬季海表温度经验正交展开的第二特征向量表明,海表温度的距平分布有南北差异的异常特征;其中心位置和中国东北地区夏季降水与冬季大西洋海表温度相关显著区中心基本重合北大西洋冬季海表温度出现南暖北冷异常时,同期北大西洋中高纬度地区的阻塞形势偏强,与之相对称的北太平洋北部的阻塞高压也偏强,对应来年夏季东亚西风环流指数偏低,造成东北区夏季降水偏多;反之亦然。  相似文献   

9.
桂林地区降水及茅茅头大岩滴水滴速和现代碳酸盐的碳氧同位素研究表明:(1)滴水沉积的δ18O达到了同位素沉积平衡,洞穴滴水的δ18O与同期降雨的δ18O值呈正相关关系;(2)在旱季和湿季交替时,滴水δ18O值滞后于降雨δ18O,受活塞效应的影响;(3)δ13C难以达到同位素沉积平衡,主要受滴水动力学影响;(4)同一洞穴不同滴水对环境的响应不同,如果洞穴顶板覆盖较厚,水分在土壤和岩层中滞留时间较长,滴水则反映受到平滑作用的降雨,反之则波动较大.  相似文献   

10.
该文利用美国 NCEP再分析资料 2 4年 (1976~ 1999年 )的逐日 12 h欧亚大陆 (0°E~15 0°E,2 0°N~ 90°N) 5 0 0 h Pa位势高度场资料 ,对阻塞高压 (简称阻高 )的活动进行了统计分析。结果表明 ,阻高主要发生在乌拉尔山地区。阻高活动有明显的季节性变化 ,春夏季阻塞形势发生得最多 ,持续时间最长 ,秋季最少且持续时间短。小波分析和离散功率谱分析都表明阻高发生的频数存在明显的年际变化 ,主要包含 3~ 4年和准 8年的周期振荡。进一步研究表明 ,乌拉尔山附近 (5 0°N~ 80°E)的阻高活动与夏季江淮流域的降水有着很好的正相关 ,与华南、华北、东北区域的降水有着很好的负相关 ;而贝加尔湖附近 (80°E~ 12 0°E)的阻高与中国东部的降水关系则正好相反。冬春季 (1~ 3月 )阻高活动对当年夏季的降水有着一定的中长期预报意义。  相似文献   

11.
The composition and distribution of helium and oxygen isotopes in samples of seawater obtained at depths from surface to 300 m in the western Pacific(7°-26°N,122°-130°E) were discussed in detail.The results show that both δ18O and δ3He isoline extend eastward in the Pacific side of the Bashi Channel, which may suggest that the South China Sea water intrudes into the western Pacific by the Bashi Channel.  相似文献   

12.
-Mainly on the basis of the data obtained during PRC/US bilateral TOGA cruises, abnormal variation occurred during the 1986/1987 El Nino is shown in this paper about the thermal structure and circulation of the upper western tropical Pacific Ocean. The effects of the abmormal variation on the subtropical high over the Northwest Pacific Ocean are discussed. During the El Nino: (1) In the east part of the western tropical Pacific Ocean (the subsurface temperature data on the 165° E section are taken as an example), the water wanner than 29 C in the upper layer spread on the longitudinal section and positive temperature anormalies appeared in a large area of the sea surface. (2) In the west part of the western tropical Pacific Ocean (the subsurface temperature data on the 137°E section are representative ), the cross section occupied by the upper layer warmer water ( T >28 ℃ ) became shrunk, and the sea surface temperature showed negative amomalies. (3) The eastward flows in the upper layer of the 165°  相似文献   

13.
Study about water characteristics(temperature and salinity) from the World Ocean Database(WOD) was conducted in the area of southern South China Sea(SSCS), covering the area of 0°–10°N, 100°–117°E. From interannual analysis, upper layer(10 m) and deep water temperature(50 m) increased from 1951 until 2014. Monthly averaged show that May recorded the highest upper layer temperature while January recorded the lowest. It was different for the deep water which recorded the highest value in September and lowest in February. Contour plot for upper layer temperature in the study area shows presence of thermal front of cold water at southern part of Vietnam tip especially during peak northeast season(December–January). The appearances of warm water were obviously seen during generating southwest monsoon(May–June). Thermocline study revealed the deepest isothermal layer depth(ILD) during peak northeast and southwest monsoon. Temperature threshold at shallow area reach more than 0.8°C during the transitional period. Water mass study described T-S profile based on particular region. Water mass during the southwest monsoon is typically well mixed compared to other seasons while strong separation according to location is very clear. During transitional period between northeast monsoon to southwest monsoon, the increasing of water temperature can be seen at Continental Shelf Water(CSW) which tend to be higher than 29°C and vice versa condition during transitional period between southwest monsoon to northeast monsoon. Dispersion of T-S profile can be seen during southwest monsoon inside Tropical Surface Water(TSW) where the salinity and temperature become higher than during northeast monsoon.  相似文献   

14.
西风爆发、次表层暖水东移与厄尔尼诺现象   总被引:9,自引:2,他引:7       下载免费PDF全文
利用最近20 a的大气海洋资料,分析了厄尔尼诺事件与赤道太平洋西风异常以及赤道太平洋次表层海温之间的关系.结果表明,赤道西太平洋(5°S~5°N,120°~160°E)和赤道中东太平洋(5°S~5°N,160°E~160°W)西风异常都存在着与厄尔尼诺周期一致的年际变化,但前者还包含有显著的2~3个月季节内振荡.赤道西太平洋次表层冷暖水东移也呈现年和年际时间尺度的振荡周期.在厄尔尼诺发生前,赤道西太平洋次表层海水出现持续性增暖,赤道西太平洋西风异常频率加快,强度增强.随后赤道中太平洋(160°E~160°W)出现持续性(3个月以上)强西风异常(即西风爆发),并进一步向东扩展,同时次表层暖水沿着赤道波导东移到赤道东太平洋混合层,导致赤道东太平洋海表大面积异常增暖,形成一次厄尔尼诺现象.最后,模式模拟了1980~1984年赤道太平洋海温的变化,进一步证实了赤道纬向西风异常对暖水东移起着重要的作用.  相似文献   

15.
In this study, 13 groups of silicon and oxygen isotopes and major elements of the basalts near the East Pacific Rise 13°N are used to study the fractionation of silicon and oxygen isotopes. Among these data, δ30Si values of basalts vary from -0.4%o to 0.2%o with a mean value of δ30Si of (-0.18±0.22)%o. The δ180 values range from 4.1%o to 6.4%o with a mean δ180 value of (+5.35±0.73) %0. Since the δ30Si values increase in the series of basalt-basaltic andesite- andesite, and δ180 values display a positive correlation with the SiO2 content, we propose that the fractionation of silicon and oxygen isotopes is influenced by the SiO2 content in igneous rocks. Compared with the igneous rocks from Manus Basin with clinopyroxene as their dominant mineral phase, MORBs in this study containing olivine and plagioclase as primary minerals have lower δ180 and δ30Si values, indicating that the fractionation of silicon and oxygen isotopes is also affected by different Si-O bridges in silicate minerals. Furthermore, our samples from the EPR are defined as E-MORB based on K/Ti ratios. Probably, the difference in δ30Si and δ30O between our samples and a normal MORB are cause by the enriched components in E-MORBs.  相似文献   

16.
以湛江降水为研究对象,利用收集的2019年汛期68个降水样品及同期气象资料,采用同位素示踪技术,结合HYSPLIT(Hybrid Single-Particle Lagrangian Integrated Trajectory)模式溯源,分析了湛江地区汛期降水稳定同位素的变化与水汽源地的关系,并对5个代表性的降水个例进行了诊断分析。结果表明:1)湛江地区汛期局部降水线为δD=8.02318O-0.7037,R2=0.954,n=68;前汛期季风带来西太平洋的水汽,18O含量丰富;后汛期降雨主要取决于局部大气环流,一定程度受云下二次分馏影响,δD和18O偏低。2)前汛期西南季风爆发前,湛江降水的水汽主要源于副热带高压外围东南气流输送的西太平洋水汽,西南季风爆发后,南海、孟加拉湾为其水汽源地;后汛期热带系统带来的降水,南海、孟加拉湾为主要水汽源地;非热带系统带来的降水,孟加拉湾为主要水汽源地。  相似文献   

17.
Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats.  相似文献   

18.
2003-2012年间白令海峡断面淡水构成的时空变化   总被引:3,自引:1,他引:2  
潘红  陈敏  童金炉  邱雨生  郑敏芳 《海洋学报》2015,37(11):135-146
通过对2003-2012年间白令海峡64.3°N断面海水氧同位素组成的分析,应用海水δ18 O值和盐度的质量平衡关系区分出淡水中河水和海冰融化水组分的贡献,探讨白令海峡淡水组成的分布特征及其年际变化。研究表明,断面东侧阿拉斯加沿岸水影响区呈现低δ18 O值、低盐、高温、高河水组分的特征,西侧阿拉德尔水具有高δ18 O值、高盐、低海冰融化水的特征,中部白令陆架水的δ18 O值、盐度和淡水组成则居于上述二者之间。阿拉斯加沿岸水影响区河水组分的份额约为阿拉德尔水和白令陆架水的2倍,并呈现出2010年2012年2003年2008年的时间变化规律,受控于育空河入海径流量的时间变化。白令陆架水和阿拉斯加沿岸水影响区的海冰融化水份额较为接近,均比阿拉德尔水影响区的海冰融化水份额高约45%。海冰融化水的年际变化表现出2003年2008年≈2012年2010年的规律,受控于白令海海冰的年际变动。从断面淡水构成看,通过白令海峡的淡水平均由46%的河水和54%的海冰融化水构成,且阿拉德尔水、白令陆架水和阿拉斯加沿岸水影响区河水组分与海冰融化水组分的比值自2003年至2012年间呈增加趋势,证明太平洋入流中淡水构成的变化对北冰洋海冰的融化也起着一定的作用。  相似文献   

19.
Evidence from geochemical tracers (salinity, oxygen, silicate, nutrients, alkalinity, dissolved inorganic carbon (DIC), carbon isotopes (δ13CDIC) and radiocarbon (Δ14C)) collected during the Pacific Ocean World Ocean Circulation Experiment (WOCE) voyages (P10, P15, P17 and P19) indicate there are three main water types at intermediate depths in the Pacific Ocean; North Pacific Intermediate Water (NPIW), Antarctic Intermediate Water (AAIW) and Equatorial Pacific Intermediate Waters (EqPIW). We support previous suggestions of EqPIW as a separate equatorial intermediate depth water as it displays a distinct geochemical signature characterised by low salinity, low oxygen, high nutrients and low Δ14C (older radiocarbon). Using the geochemical properties of the different intermediate depth waters, we have mapped out their distribution in the main Pacific Basin.From the calculated pre-formed δ13Cair–sea conservative tracer, it is evident that EqPIW is a combination of AAIW parental waters, while quasi-conservative geochemical tracers, such as radiocarbon, also indicate mixing with old upwelling Pacific Deep Waters (PDW). The EqPIW also displays a latitudinal asymmetry in non-conservative geochemical tracers and can be further split into North (NEqPIW) and South (SEqPIW) separated at ~2°N. The reason for this asymmetry is caused by higher surface diatom production in the north driven by higher silicate concentrations.The δ13C signature measured in benthic foraminifera, Cibicidoides spp.13CCib), from four core tops bathed in AAIW, SEqPIW and NPIW, reflects that of the overlying intermediate depth waters. The δ13CCib from these cores show similarities and variations down-core that highlight changes in mixing over the last 30,000 yr BP. The reduced offset between the δ13CCib of AAIW and SEqPIW during the last glacial indicates that AAIW might have had an increased influence in the eastern equatorial Pacific (EEP) region at this time. Additional intermediate depth cores and other paleo-geochemical proxies such as Cd/Ca and radiocarbon are required from the broader Pacific Ocean to further understand changes in intermediate depth water formation, circulation and mixing over glacial/interglacial cycles.  相似文献   

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