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1.
XU Jun BAO Jingyang LIU Yanchun YU Caixia 《地球空间信息科学学报》2007,10(2):100-104
A tide model (named DN1.0), which contains 12 principal constituents over China seas and the Northwest Pacific is estimated by along-track harmonic analysis with TOPEX/Poseidon altimetry data taken from 1993 to 2002. CSR3.0, FES95.2 and DN1.0 are used respectively to detide the data for the time series of sea level anomaly (SLA) in the Yellow Sea, East China Sea, South China Sea and Northwest Pacific. The SLA curves and the power spectral density show that the major components that exist in SLA in China seas arise from the error of the tide models. 相似文献
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利用T/P测高数据反演了中国近海及西北太平洋海域的潮汐参数,构造了CSR3.0、FES95.2和T/P反演的海潮模型改正下的海面高时间序列,通过海面高变化曲线及功率谱的比较确定了利用测高数据发现的海平面季节内变化主要是潮汐模型误差的贡献. 相似文献
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An algorithm (differential mode) is presented for the improvement of harmonic tidal analysis along T/P tracks, in which the differences between the observed sea surface heights at adjacent points are taken as observations. Also, the observation equations are constrained with the results of the crossover analysis; the parameter estimations are performed at 0.1° latitude intervals by the least squares. Cycle 10 to 330 T/P altimeter data covering the China Sea and the Northwest Pacific Ocean (2°-50° N,105°-150° E) are adopted for a refined along-track harmonic tidal analysis, and harmonic constants of 12 constituents in 8 474 points are obtained, which indicates that the algorithm can efficiently remove non-tidal effects in the altimeter observations, and improve the precision of tide parameters. Moreover, parameters along altimetry tracks represent a smoother distribution than those obtained by traditional algorithms. The root mean squares of the fitting errors between the tidal height model and the observations reduce from 11 cm to 1.3 cm. 相似文献
4.
中国近海1992~1998海平面变化监测与分析 总被引:14,自引:1,他引:13
利用Topex/Poseidon和ERS-1卫星测高资料采用“共线”法计算出1992-10~1998-06中国近海海域海平面及其变化。在扣除T/P卫星测高仪的零点漂移影响后,发现与全球海平面上升率(+2.1±1.3)mm/a相比,不同海域的海平面变化趋势大不相同,黄、东、南海的海平面年变化率分别为:(+3.44±0.61)mm/a,(+3.12±0.47)mm/a,(-1.41±0.48)mm/a。从海平面变化异常中可以看出1993,1994,1997~1998年3次El Nino异常对中国近海海域海平面的影响是南海海域最大,东海次之,黄海最小。除了对海平面进行传统的频谱分析外,还进行了多分辨率的小波分析,还发现在上述3个海域中除了年周期变化较为稳定外,半年及季节(100 d)周期项存在着时间漂移。此外,在上述3个海域还存在着明显的两个月(62 d)周期的变化,其激发原因在此做了初步探讨。 相似文献
5.
中国东海叶绿素浓度变化分析及其海水温度响应 总被引:1,自引:0,他引:1
海洋叶绿素浓度时空格局分析及与海水温度的响应研究对于海洋资源的开发和保护及赤潮的预防具有重要意义。本文基于2004—2018年东海叶绿素浓度和海水温度数据运用趋势分析及ArcGIS10.2软件,对东海叶绿素浓度作了时空分析研究,并结合海水温度进行了回归分析,以探究叶绿素对海水温度变化的响应机制。结果表明:①东海叶绿素浓度在2004—2018年间没有明显的年际变化特征。年内则随时间上下波动,冬季为波峰,夏季为波谷。离海岸带越近,叶绿素浓度越高。②东海海域海水温度在年际尺度上呈波动式起伏变化。在季节尺度上夏秋两季温度较高,春季次之,冬季最低。从沿海到外海海域海温逐渐升高。③就空间相关性而言,东海海域叶绿素浓度与海水温度整体呈负相关,在不同海域相关程度不同。长江口和外海区域叶绿素浓度与海水温度具有很强的相关性;在沿海区域,由于受到城市环境、经济发展及人类生产生活的影响,海水温度与叶绿素浓度的相关性不明显。 相似文献
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利用卫星测高资料推求西北太平洋海域的海洋大地水准面 总被引:3,自引:0,他引:3
本文根据卫星测高数据和海面动力地形资料,绘制了不相上下北太平洋海域局部大地水准面的精细结构图,对解决卫星测高技术中大地水准面积和海面地形的可分性问题作了初步尝试。 相似文献
9.
HWANG Chenway 《地球空间信息科学学报》2010,13(2):144-149
The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution,
three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter
data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China
Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing
of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more
suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from
retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates
that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the
same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08. 相似文献
10.
Jianhua Wan Qinting Sun Shanwei Liu Yinlong Li 《Journal of the Indian Society of Remote Sensing》2018,46(12):1939-1947
The characteristics of sea-level change in the China Sea and its vicinity are studied by combining TOPEX/Poseidon (T/P), Jason-1, Jason-2, and Jason-3 altimeter data. First, the sea-surface height is computed by using monthly data via collinear adjustment, regional selection, and crossover adjustment. The sea-level anomaly (SLA) from October 1992 to July 2017 is calculated based on the difference that is obtained by the value derived from the inverse distance weighting method to interpolate the CNES_CLS15 model value at a normal point. By analyzing the satellite data at the same time in orbit, three mean bias groups over the China Sea and its vicinity are obtained: the difference between T/P and Jason-1 is ??11.76 cm, the difference between Jason-1 and Jason-2 is 9.6 cm, and the difference between Jason-2 and Jason-3 is 2.42 cm. To establish an SLA series for 25 years in the study area, the SLAs are corrected. Mean rate of sea-level rise of the Bohai Sea, Yellow Sea, East China Sea, and South China Sea of 4.87 mm/a, 2.68 mm/a, 2.88 mm/a, and 4.67 mm/a, respectively, is found by analyzing the series of SLAs. 相似文献
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This paper aims at the prediction of both global mean sea level anomalies (SLAs) and gridded SLA data in the east equatorial Pacific obtained from TOPEX/Poseidon and Jason-1 altimetric measurements. The first prediction technique (denoted as LS) is based on the extrapolation of a polynomial-harmonic deterministic least-squares model describing a linear trend, annual and semi-annual oscillations. The second prediction method (denoted as LS + AR) is a combination of the extrapolation of a polynomial-harmonic model with the autoregressive forecast of LS residuals. In the case of forecasting global mean SLA data, both techniques allow one to compute the predictions of comparable accuracy (root mean square error for 1-month in the future is of 0.5 cm). In the case of predicting gridded SLA data, the LS + AR prediction method gains significantly better prediction accuracy than the accuracy obtained by the LS technique during El Niño 1997/1998, La Niña 1998/1999 and during normal conditions. 相似文献
13.
验潮站观测的海面高度数据是监测海平面变化以及确定平均海面的重要基础观测信息,利用滑动时段法和时段累积法对验潮站不同观测时段相对海平面变化速率的差异进行了分析,讨论了时段选择效应对计算相对海平面变化的影响,并利用美国东海岸验潮站观测数据对分析结果进行了补充实验。实验结果表明,不同观测时段相对海平面变化速率差异最大可达27.5 mm/a,相邻年份逐年滑动结果的最大互差可达7.1 mm/a;随着观测时段年数的累积,相对海平面变化速率增加,为了获得0.5 mm/a中误差精度的相对海平面变化速率,验潮站需要的观测年数为22~28 a;而要获得0.2 mm/a中误差精度的相对海平面变化速率,则需要40~54 a的观测年数,这与使用美国验潮站观测数据的补充实验结论一致。 相似文献
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Annual amphidromes: a common feature in the ocean? 总被引:1,自引:0,他引:1
The scientific term "amphidrome" is usually associated with tides in oceanography. The dozen tidal amphidromes observed in the ocean are critical points that determine the fundamental pattern of the global tidal system. Exploration of recently available satellite data with an unprecedented 1-2 decades duration suggests that an amphidrome is not a tide-only phenomenon in the ocean. Analysis of altimeter-derived sea level anomaly (SLA) data and radiometer-derived sea surface temperature (SST) data allows ten amphidromic points to be clearly identified in annual SLA and SST variations. These amphidromes are located in the tropical areas of the Pacific, Atlantic, and Indian oceans. Their existence implies that the annual cycle (in time) of the atmosphere-ocean system is translated into a rotary variation (in space) for many of the geophysical parameters. It can be concluded that annual amphidromes are common, the knowledge of which is of particular interest, given their annually "constant" nature, for the monitoring and understanding of oceanic, climatic, as well as biological variabilities at seasonal to decadal scales, which strongly affect many aspects of the natural and societal activities on the globe. 相似文献
16.
首先利用重力恢复与气候实验(gravity recovery and climate experiment,GRACE)卫星重力、卫星测高和海洋温盐数据分析了2003-2012年间南海海水质量的变化特征,进而结合海洋和气象资料探讨了厄尔尼诺和南方涛动(El Ni?o-Southern Oscillation,ENSO)、净淡水通量、海水体积输送和陆地径流在此期间对南中国海海水质量变化的影响。研究结果表明,南海海水质量变化主要受海面净淡水通量和海水体积输送的联合调制影响,周边陆地径流对其影响有限。南海海水质量季节性变化显著,且具有明显的长期增加趋势;ENSO通过改变降水和黑潮自吕宋海峡流入南海的水量影响南海海水质量,使得南海海水质量存在着显著的具有ENSO特征的年际变化。 相似文献
17.
The impact of the dynamic sea surface topography on the quasi-geoid in shallow coastal waters 总被引:1,自引:1,他引:0
In this study, we examine the impact of instantaneous dynamic sea surface topography (DT) corrections to be applied to altimeter-derived sea surface slopes on the quasi-geoid in the shallow and coastal waters of the North Sea. In particular, we investigate the added value of DT corrections obtained from a shallow-water hydrodynamic model. These corrections comprise the contributions of ocean tides, wind- and pressure-driven (surge), and density-driven (baroclinic) water-level variations including the interactions between them. As a reference, we used tidal corrections derived from the global ocean tide model GOT4.7, surge corrections derived from the MOG2D model, and corrections for the time-averaged baroclinic contribution computed as differences between the DTU10 mean sea surface model and the EGG08 quasi-geoid. From a spectral analysis, we found that the baroclinic and surge parts of the DT mainly contribute to improvements in the signal-to-noise ratio (SNR) at longer wavelengths down to $100{-}200~\hbox {km}$ and that the improvements increase towards the southern North Sea. We also found that the shallow-water hydrodynamic model provides better tidal corrections compared to the GOT4.7 global ocean tide model, which are most pronounced in the southern North Sea and affect almost the entire spectrum. Very small differences (mostly below ${\pm } 2~\hbox {cm}$ ) are observed between the quasi-geoid solutions obtained using the different sets of DT corrections. We showed that the variance component estimation provides too optimistic variance factors for the shipboard data set relative to the altimeter-derived quasi-geoid slopes. Hence, the limited impact of DT corrections is due to the fact that altimeter-derived quasi-geoid slopes hardly contribute to the estimated quasi-geoid if shipboard gravity data are included. When computing quasi-geoid solutions without shipboard gravity data, we found that less accurate or incomplete DT corrections may cause errors in the quasi-geoid with systematic spatial patterns. These systematic patterns disappear or are reduced significantly when using the DT corrections provided by the shallow-water hydrodynamic model. The main contributor to this improvement is the better tidal correction provided by the shallow-water hydrodynamic model compared to the GOT4.7 global ocean tide model. Seen the improvements of the global ocean tide models over the last two decades, we expect that in the near future global ocean tide models perform as well as dedicated regional models such as DCSM. Critical issue is, however, access to high-quality local bathymetric data. 相似文献
18.
利用验潮站资料的中国近岸海潮模型精度评估 总被引:1,自引:0,他引:1
针对全球海潮模型在我国近海海域精度较差的问题,该文采用中国沿岸30个长期验潮站的调和常数,对比了3种全球海潮模型DTU10、TPXO7.2、NAO.99b和1个区域海潮模型NAO.99Jb在中国沿岸的准确度。通过海潮模型与验潮站分潮的振幅中误差、迟角中误差以及8个主要分潮的预报误差,对渤海、黄海、东海和南海北部进行了详细的分析。结果表明,NAO.99Jb在中国海域精度最高,NAO.99b次之。在渤海海域,DTU10在Q_1分潮精度最高,NAO.99b在K2分潮精度最高,其余分潮均是NAO.99Jb精度最高;在黄海海域,NAO.99b在Q_1分潮精度最高,其余分潮均是NAO.99Jb精度最高;在东海海域,DTU10在Q_1分潮精度最高,TPXO7.2在P1精度最高,NAO.99Jb在O1、M2分潮精度最高,其余分潮均是NAO.99b精度最高;在南海北部海域,DTU10在N2、S2分潮精度最高,其余分潮均是NAO.99Jb精度最高。 相似文献
19.
Analysis of some systematic errors affecting altimeter-derived sea surface gradient with application to geoid determination over Taiwan 总被引:3,自引:1,他引:3
C. Hwang 《Journal of Geodesy》1997,71(2):113-130
This paper analyzes several systematic errors affecting sea surface gradients derived from Seasat, Geosat/ERM, Geosat/GM,
ERS-1/35d, ERS-1/GM and TOPEX/POSEIDON altimetry. Considering the data noises, the conclusion is: (1) only Seasat needs to
correct for the non-geocentricity induced error, (2) only Seasat and Geosat/GM need to correct for the one cycle per revolution
error, (3) only Seasat, ERS-1/GM and Geosat/GM need to correct for the tide model error; over shallow waters it is suggested
to use a local tide model not solely from altimetry. The effects of the sea surface topography on gravity and geoid computations
from altimetry are significant over areas with major oceanographic phenomena. In conclusion, sea surface gradient is a better
data type than sea surface height. Sea surface gradients from altimetry, land gravity anomalies, ship gravity anomalies and
elevation data were then used to calculate the geoid over Taiwan by least-squares collocation. The inclusion of sea surface
gradients improves the geoid prediction by 27% when comparing the GPS-derived and the predicted geoidal heights, and by 30%
when comparing the observed and the geoid-derived deflections of the vertical. The predicted geoid along coastal areas is
accurate to 2 cm and can help GPS to do the third-order leveling.
Received 22 January 1996; Accepted 13 September 1996 相似文献
20.
区域参考框架是实现高精度区域大地形变观测和滑坡灾害长期监测的基础设施。结合活动地块的划分和长期的GNSS观测结果,笔者将我国大陆和海域初步划分为7个“刚性骨架地块”,简称“刚性地块”,拟建立覆盖我国陆海全域的区域参考框架系列:东北、华北、华南、西北、青藏、川滇及南海参考框架。本文介绍了从全球参考框架(IGS14)到区域参考框架的坐标转换方法,并例举了华北参考框架(NChina20)和华南参考框架(SChina20)在滑坡长期监测和滑坡初动自动识别领域的应用。 相似文献