共查询到20条相似文献，搜索用时 122 毫秒
1.
格陵兰岛附近海域海平面变化的初步研究 总被引：1，自引：0，他引：1
利用17年5个月的卫星高度计资料,探讨格陵兰岛附近海域海平面的季节变化和年际变化特征,结果表明,该区域海平面变化存在显著的季节信号和年际信号。近20a来,格陵兰岛附近海域海平面的平均上升速率为1.7mm/a,小于全球海平面的平均上升速率。该海域的海平面变化存在很强的区域性,通常多年平均海面高度异常(SSHA)大的海区,海平面上升速率也大;多年平均SSHA低的海区,海平面上升速率则较小。EOF分析表明第一模态为季节模态,整个海域第一空间模态的位相相同,说明该海域海平面的季节变化趋势是相同的。该区域的SSHA与海冰面积指数呈负相关,海平面的季节变化受海冰面积大小的影响显著。SSHA与经向风应力距平的低频分量具有很好的正相关性,与纬向风应力距平的低频分量具有不显著的负相关,说明该海域海平面的年际变化受风应力的影响显著。 相似文献
2.
1993—2006年北太平洋海平面变化特征及影响因素 总被引：2，自引：0，他引：2
利用1993—2006年间卫星高度计资料分析北太平洋海平面的变化特征,结合同期上层海洋温度、盐度数据以及风应力资料分析比容海平面和风对海平面变化的影响。结果显示:1993—2006年北太平洋上升海域主要位于洋盆西侧中低纬度海域,高纬度海域及大洋东侧的中低纬度海域海平面呈下降趋势;同期比容海平面线性速率的空间分布与海平面相似。整个北太平洋海平面高度平均线性上升速率为2.9 mm/a,比容海平面平均线性上升速率为1.4 mm/a。比容变化对海平面上升趋势的贡献为47.5%。北太平洋海平面的季节变化占绝对优势,主要为1和0.5 a周期,对海平面距平做EOF,其第一和第三模态为季节模态。海平面季节变化的影响因素中,比容变化与海平面有相同的季节变化周期,比容海平面距平EOF的第一和第三模态为季节模态,分别与海平面的第一和第三模态空间分布相似,时间系数相关性好,比容变化在海平面季节特征中起到最主要作用。另一个因素风场主要通过Ekman抽吸和Rossby波的西传影响海平面的分布,其季节特征对海平面的季节特征有影响。北太平洋海平面也具有28个月的年际变化周期,海平面距平EOF第二和第四模态表现出年际变化特征。比容变化也具有28个月的显著周期,其距平场的第二和第四模态为年际变化模态,其中第二模态与海平面第二模态空间分布相似,时间系数相关性很好,海平面年际变化中比容起到重要影响。 相似文献
3.
由于分辨率不足等原因，当前大部分全球耦合气候模式对南海等海洋区域的模拟能力仍然较低。本文基于超高分辨率（Ultra high-resolution） CESM-UHR耦合模式（大气和海洋水平分辨率分别达到约25 km和约10 km）研究了南海动力海平面对全球变暖的响应。研究发现：（1） CESM-UHR能够较好地模拟出南海冬、夏季节性动力海面高度和表层环流变化；（2）在四倍二氧化碳试验下，冬季南海动力海平面变化呈现出中部低、近岸高的分布特征；夏季则呈现出西北部低、东南部高的分布特征，分别对应冬、夏表层地转流增强趋势；（3）冬、夏动力海平面变化特征与风应力旋度变化具有很好的对应关系；（4）全球变暖下南海海平面变化存在季节循环放大效应，这将增大南海极端水位灾害风险。 相似文献
4.
渤黄海海平面的变化及其与ENSO的关系 总被引：3，自引：0，他引：3
利用1992年12月至2007年5月的高度计资料,研究了渤黄海海平面的变化特征。统计分析表明,近14a间渤海及北黄海、中央黄海海平面的平均上升高度分别为45.9mm和34.7mm,各海域的海平面上升速度不完全相同。研究发现,南方涛动指数(SOI)、纬向风应力距平都与渤海及北黄海、中央黄海的SLA呈负相关性,渤黄海海平面显著受SOI、纬向风应力调制,并且,SOI与渤黄海海域的风场之间有良好相关。将坐标系进行旋转后,获得与当地海平面异常相关最大的风应力方向。对SLA与新坐标系下风应力距平u的低频分量分析发现,渤海及北黄海海区、中央黄海对海平面影响最大的风应力距平u方向分别为东偏南20°方向、东偏南8°方向,风应力距平u分量与SLA、SOI的低频分量呈现更好的相关性。ENSO通过大气环流过程对渤黄海海域的风场产生影响,当地风场通过纬向风应力对渤黄海海平面的年际变化产生调制作用。因此,ENSO可以通过风应力对渤黄海海平面产生影响。 相似文献
5.
中国沿海海平面的上升预测模型 总被引：8，自引：1，他引：8
温室效应引起的全球海平面上升，已为世界各海洋国家所关注，研究表明，近２０年多年以来，我国沿海的海平面以１．５ｍｍ／ａ的速率上升，这与全球海平面上升的趋势是一致的，为了预测海平面的这种上升趋势，本文试图从温室效应引起的全球海平面上升和结合我国海海平面变化特点提出了我国的海平面变化预测模型，即中国沿海海平面上升趋势既取决于全球温室效应的增强，又受到沿海地壳升降和地面下沉的影响，文中给出了我国海平面变化 相似文献
6.
本研究基于非平稳序列极值理论，定量分析极端水位事件年超越概率受海平面上升的影响；以工程设计使用年限内极端水位发生概率作为控制条件，构建考虑海平面上升的极值水位计算方法；结合平均海平面的长期变化过程，推算海平面上升下的极值水位。基于全球10个验潮站历史水位观测资料，验证历史平均海平面长期变化与高、低水位耿贝尔分布位置参数变化的一致性以及构建方法的合理性。结合政府间气候变化专门委员会对海平面上升的预测，推算和对比分析不同海平面上升情景下的极值水位，并评估相应极值水位在当前极值分布中的重现期。 相似文献
7.
热带太平洋海面风的年际变化对海平面变化的影响 总被引：1，自引：0，他引：1
海平面变化研究的意义在于掌握其变化规律,预测其未来变化及其可能对人类生存生活环境产生的影响。本文使用随机动态和相关分析方法分析卫星高度计资料,结果发现,除了显著的季节信号外,全球海平面存在显著的2～7a的年际周期,相关分析结果显示,这一年际周期跟ENSO密切相关。在太平洋不同纬度海平面对ENSO事件的响应整体上呈现出高纬衰减的变化特征。ENSO期间海平面变化剧烈,在热带太平洋区域,海平面变化受纬向风应力的调制,具有区域特征,海平面的年际变化与赤道流相关达0.6以上,揭示了风主要是通过Ekman作用影响海平面变化。 相似文献
8.
三沙市海域海平面变化 总被引：5，自引：3，他引：2
使用1993-2011年的台站和卫星高度计资料详细分析了三沙市海域近19 a的海平面变化特征及规律。结果表明:三沙市周边海域海平面存在明显的季节变化,且区域特征明显。海平面变化除了明显的年和半年周期,2~3 a、4~7 a和准9 a的周期也较显著。海平面长期变化呈现明显的波动上升趋势,且空间分布上区域特征显著,西沙群岛南部海域海平面上升趋势最强,西沙群岛北部与中沙群岛西部次之,南沙群岛东部海平面上升速率较快,南沙群岛西部上升趋势最弱。受大气环流等异常气候事件的影响,1998年和2010年海平面的年际变化波动较大,年变化振幅显著偏高。未来三沙市海平面将继续上升,预计2030年、2050年、2070年和2100年海平面将比常年分别升高约11 cm、20 cm、30 cm和45 cm。 相似文献
9.
采用能够反映斜压大洋对大尺度海表面风应力旋度响应的一层半约化重力模式研究菲律宾以东太平洋海区Rossby波与海平面年际变化的关系.模式分别利用海区东侧验潮站和卫星高度计海表面数据作初始东边界,对Rossby波西传路径上的风应力旋度进行积分,得到西侧海平面信号.结果发现,模拟的海平面信号跟验潮站和卫星高度计资料相关性很高,并能模拟出海平面年际变化特征和低(高)异常信号由东侧产生并向西传播的过程,反映了一阶斜压Rossby波对菲律宾以东太平洋海区年际海平面变化的动力机制. 相似文献
10.
MU Lin CHI Yong-xiang LIU Shou-hua SONG Jun LIN Xiao-pei LI Yan ZHANG Jian-li 《海洋通报(英文版)》2013,(2):26-36
应用ROMS数值模式配置基本实验模拟了2004年到2006年中国东部海域海平面的季节变化。模拟结果与TOPEX／Poseidon（T／P）卫星高度计观测结果基本一致,海平面年较差从中国沿岸到黑潮路径逐渐变小。将数值模式的风应力项去掉,配置对比实验。与基本实验结果对比发现,对比实验海平面仍然具有季节变化,但是闽浙沿岸和苏北沿岸海平面春夏季异常偏低、秋冬季异常偏高现象消失,中国沿岸向太平洋的海平面变化减弱。春季和秋季,渤、黄海和黑潮附近海平面异于东海的现象减弱。对比实验海平面的年较差的数值明显减小,从近岸向黑潮海平面年较差渐变的过程消失。整个渤黄海的海平面年较差近似。对比实验海平面年较差占基本实验海平面年较差比率从近岸向黑潮路径逐渐增大。 相似文献
11.
TAI Chang-Kou 《海洋学报(英文版)》2011,30(4):102-106
An attempt is made to infer the global mean sea level(GMSL) from a global tide gauge network and frame the problem in terms of the limitations of the network. The network,owing to its limited number of gauges and poor geographical distribution complicated further by unknown vertical land movements,is ill suited for measuring the GMSL. Yet it remains the only available source for deciphering the sea level rise over the last 100 a. The poor sampling characteristics of the tide gauge network have necessitated the usage of statistical inference. A linear optimal estimator based on the Gauss-Markov theorem seems well suited for the job. This still leaves a great deal of freedom in choosing the estimator. GMSL is poorly correlated with tide gauge measurements because the small uniform rise and fall of sea level are masked by the far larger regional signals. On the other hand,a regional mean sea level(RMSL) is much better correlated with the corresponding regional tide gauge measurements. Since the GMSL is simply the sum of RMSLs,the problem is transformed to one of estimating the RMSLs from regional tide gauge measurements. Specifically for the annual heating and cooling cycle,we separate the global ocean into 10-latitude bands and compute for each 10-latitude band the estimator that predicts its RMSL from tide gauges within. In the future,the statistical correlations are to be computed using satellite altimetry. However,as a first attempt,we have used numerical model outputs instead to isolate the problem so as not to get distracted by altimetry or tide gauge errors. That is,model outputs for sea level at tide gauge locations of the GLOSS network are taken as tide gauge measurements,and the RMSLs are computed from the model outputs. The results show an estimation error of approximately 2 mm versus an error of 2.7 cm if we simply average the tide gauge measurements to estimate the GMSL,caused by the much larger regional seasonal cycle and mesoscale variation plaguing the individual tide gauges. The numerical model,Los Alamos POP model Run 11 lasting 3 1/4 a,is one of the best eddy-resolving models and does a good job simulating the annual heating and cooling cycle,but it has no global or regional trend. Thus it has basically succeeded in estimating the seasonal cycle of the GMSL. This is still going to be the case even if we use the altimetry data because the RMSLs are dominated by the seasonal cycle in relatively short periods. For estimating the GMSL trend,longer records and low-pass filtering to isolate the statistical relations that are of interest. Here we have managed to avoid the much larger regional seasonal cycle plaguing individual tide gauges to get a fairly accurate estimate of the much smaller seasonal cycle in the GMSL so as to enhance the prospect of an accurate estimate of GMSL trend in short periods. One should reasonably expect to be able to do the same for longer periods during which tide gauges are plagued by much larger regional interannual(e. g.,ENSO events) and decadal sea level variations. In the future,with the availability of the satellite altimeter data,we could use the same approach adopted here to estimate the seasonal variations of GMSL and RMSL accurately and remove these seasonal variations accordingly so as to get a more accurate statistical inference between the tide gauge data and the RMSLs(therefore the GMSL) at periods longer than 1 a,i. e.,the long-term trend. 相似文献
12.
本文对比了3个不同机构提供的北冰洋月均高度计数据,发现英国极地观测与建模中心和丹麦科技大学空间中心两套数据比较一致且空间覆盖率高,适用于北冰洋海平面变化研究,而前者在数据分辨率、平滑性和与验潮站的符合程度方面均更优。对高度计和验潮站数据的分析表明,北冰洋海平面的气候态特征表现为加拿大海盆的高值和欧亚海盆的低值之间形成鲜明对比;海平面的变化以季节变化和北极涛动引起的低频变化为主,加拿大海盆的季节和年际振幅均较大,俄罗斯沿岸海平面季节变化显著。2003?2014年,北冰洋平均海平面呈上升趋势,其中加拿大海盆海平面上升最快,而俄罗斯沿岸海平面有微弱下降趋势。加拿大海盆和俄罗斯沿岸由于海冰变化显著,不同高度计产品以及高度计与验潮站数据之间差别较大,使用时需慎重。 相似文献
13.
The sea surface heights (SSHs) observed by the TOPEX altimeter are compared with tide gauge data at Chichijima in Ogasawara (Bonin) Islands and hydrographic data taken around the islands, in order to quantitatively verify the altimeter observations and oceanic tide corrections by three tide models proposed by Cartwright and Ray (1991), Rayet al. (1994), and Maet al. (1994). First, performance of the new tide models is assessed by comparing tidal variations consisting of diurnal and semi-diurnal constituents with the tide gauge data at Chichijima. The tide model proposed by Rayet al. gives the smallest root-mean-squared (rms) difference of 2.61 cm. Errors in amplitude and phase in each tide model are evaluated by spectral analysis. The TOPEX SSHs corrected by the tide models are compared with sea level data at Chichijima. A long-term variation of a period of about 1 year is found in the residual between the SSHs and the Chichijima sea levels. This variation is also found in the difference between the dynamic height anomalies calculated from hydrographic data around the island and the Chichijima sea levels. By subtracting the long-term variation, the rms difference between the TOPEX SSHs and the Chichijima sea levels is reduced to about 4 cm and the slope of the regression line is improved to unity. The residual shows variations related to aliasing caused by incompleteness of the ocean tide correction with the repeat cycle of the altimeter observation. 相似文献
14.
Changes in the height of the ocean can be described through the relative and absolute sea level changes depending on the geodetic reference the sea level records are related to. Satellite altimetry provides absolute sea level (ASL) measurements related to the global geodetic reference, whereas tide gauges provide relative sea level (RSL) measurements related to the adjacent land. This study aims at computing the ASL surfaces for different time epochs from combined satellite altimeter and tide gauge records. A method of sea level data fusion is proposed to enable modeling of the impact of present and future sea level changes on the coast. Sea surface modeling was investigated for ten different gridding methods commonly used for the interpolation of altimeter data over the open ocean and extrapolation over the coastal zones. The performance of gridding methods was assessed based on the comparison of the gridded altimeter data and corrected tide gauge measurements. Finally, the sea level surfaces related to the GRS80 global reference ellipsoid were computed for the Mediterranean Sea over the altimeter period. In addition, the current sea level trends were estimated from both sea level measurements. 相似文献
15.
Arctic absolute sea level variations were analyzed based on multi-mission satellite altimetry data and tide gauge observations for the period of 1993–2018. The range of linear absolute sea level trends were found ?2.00 mm/a to 6.88 mm/a excluding the central Arctic, positive trend rates were predominantly located in shallow water and coastal areas, and negative rates were located in high-latitude areas and Baffin Bay. Satellite-derived results show that the average secular absolute sea level trend was (2.53±0.42) mm/a in the Arctic region. Large differences were presented between satellite-derived and tide gauge results, which are mainly due to low satellite data coverage, uncertainties in tidal height processing and vertical land movement (VLM). The VLM rates at 11 global navigation satellite system stations around the Arctic Ocean were analyzed, among which 6 stations were tide gauge co-located, the results indicate that the absolute sea level trends after VLM corrected were of the same magnitude as satellite altimetry results. Accurately calculating VLM is the primary uncertainty in interpreting tide gauge measurements such that differences between tide gauge and satellite altimetry data are attributable generally to VLM. 相似文献
16.
An Improved Calibration of Satellite Altimetric Heights Using Tide Gauge Sea Levels with Adjustment for Land Motion 总被引：2，自引：0，他引：2
Gary T. Mitchum 《Marine Geodesy》2000,23(3):145-166
Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data. 相似文献
17.
Gary T. Mitchum 《Marine Geodesy》2013,36(3):145-166
Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data. 相似文献
18.
Vertical Land Motion in the Mediterranean Sea from Altimetry and Tide Gauge Stations 总被引：1，自引：0，他引：1
We have computed estimates of the rate of vertical land motion in the Mediterranean Sea from differences of sea level heights measured by the TOPEX/Poseidon radar altimeter and by a set of tide gauge stations. The comparison of data at 16 tide gauges, using both hourly data from local datasets and monthly data from the PSMSL dataset, shows a general agreement, significant differences are found at only one location. Differences of near-simultaneous, monthly and deseasoned monthly sea level height time-series have been considered in order to reduce the error in the estimated linear-term. In a subset of 23 tide gauge stations the mean accuracy of the estimated vertical rates is 2.3 ± 0.8 mm/yr. Results for various stations are in agreement with estimates of vertical land motion from geodetic methods. A comparison with vertical motion estimated by GPS at four locations shows a mean difference of ?0.04 ± 1.8 mm/yr, however the length of the GPS time-series and the number of locations are too small to draw general conclusions. 相似文献
19.
利用1992年10月至2008年6月的卫星高度计融合资料对台湾岛周边海域（20°～28°N,117°～124°E）多年海平面变化进行分析.研究结果表明：（1）采用改进的月平均水位周期信号的谱分析方法计算多年来台湾岛周边海域海平面年均上升速率为0.34±0.02 cm/a,与该海域内的潮位站结果较为一致.（2）台湾岛周边海域海平面高度变化以1 a周期变化为主,其次为0.5 a、准2 a周期变化.（3）通过计算海平面异常的标准差得出多年来台湾海峡西南部海域海平面波动最为激烈.（4）分析了台湾岛周边海域海平面4个季节的变化情况,指出台湾岛周边海域海平面季节变化的主要驱动力是风场. 相似文献
20.
Calibration of TOPEX/Poseidon and Jason Altimeter Data to Construct a Continuous Record of Mean Sea Level Change 总被引：10，自引：0，他引：10
Jason, the successor to the TOPEX/POSEIDON (T/P) mission, has been designed to continue seamlessly the decade-long altimetric sea level record initiated by T/P. Intersatellite calibration has determined the relative bias to an accuracy of 1.6 mm rms. Tide gauge calibration of the T/P record during its original mission shows a drift of -0.1 ± 0.4 mm/year. The tide gauge calibration of 20 months of nominal Jason data indicates a drift of -5.7 ± 1.0 mm/year, which may be attributable to errors in the orbit ephemeris and the Jason Microwave Radiometer. The analysis of T/P and Jason altimeter data over the past decade has resulted in a determination of global mean sea level change of +2.8 ± 0.4 mm/year. 相似文献