近几十年来的全球海面变化

本文分析了全球914个验潮站的月平均海面观测序列.在此基础上以一定的准则对其中有长期观测记录的414个验潮站求出了各验潮站的局部视海面变化速率,并在“均衡基准”下求得了近几十年来全球海面变化的平均速率约为每年缓慢上升1.25～1.45mm.但在地区、海域之间存在明显差异.提出了特别易受海面上升影响的若干地区.     

近几十年来韩江三角洲水位变化趋势研究

利用韩江三角洲５个验潮站的潮位资料，应用高斯滤波器对月均验潮序列进行低通数字滤波，消除验潮序列中短周波动对确定海平面变化趋势的影响。由低通序列一元线性回归分析确定海平面变化趋势，由本征函数分解的特征模态计算韩江三角洲区域的水位变化趋势。     

近几十年来中国沿岸海面变化趋势的研究

本文采用平均海面一种平稳动态模型,分析中国沿岸海面变化,并作出趋势预测.中国近海40年来相对海平面变化速率平均约为1mm/a,近10a、特别是近3a来的平均海面呈上升趋势.有关3-7a的变化,主要是本海区海面对埃尔尼诺现象、黑潮大弯曲和中国沿海气候变异作出的响应.具体说,中国近海海面变化主要是由黑潮流量、本海区寒潮强弱和降水量多寡等因素决定的.本文以黄浦公园为例,用找到的周期对年均海面进行推算,5a间推算与实测值的标准差为3.9cm.     

黄、东海西部营养盐浓度近几十年来的变化

通过对以往调查资料和研究成果的总结,发现黄、东海西部海域在近40～50年中NO3-、SiO32-和PO43-浓度均发生了显著的变化,NO3-浓度快速上升,而SiO32- 和PO43-浓度显著下降.NO3-浓度的上升和SiO32-浓度的下降均与它们在长江等河流中的变化趋势一致;PO43-浓度的下降在河流以及长江口海域并不明显,而更多地体现在较为封闭的渤海、黄海.作者推测,NO3-陆源输入的增加,提高了海洋生产力,加强了浮游植物对PO43的吸收可能是造成PO43-在研究区域平均水平下降的一个原因.基于这个假设,设计了一个简单的数学模型,用以计算为了满足目前PO43-的下降量,外界NO3-输出通量所需的增长速率.结果表明,如果增长的氮通量全部是由长江等河流输出的NO3-提供,这些河流NO3-的平均浓度在近几十年中至少增加了7.8 μmol/L.     

1997年夏季西北太平洋环流模拟

采用1997年7月中日副热带环流合作调查资料,即“向阳红14”号、“东方红”两调查船CTD观测资料、日本TK和IK断面资料以及GTSPP同步资料,应用开边界情形的MOM2模式计算了西北太平洋21.875°～35.125°N,120.875°～137.125°E范围的环流,主要结果如下:在此期间,(1)黑潮在台湾以东并不存在东分支流向琉球群岛以东海域;(2)东海黑潮的流量约为30×106m3/s,日本以南黑潮流量最大约为70×106m3/s;(3)在21.875°～25°N之间大约有15×106m3/s的流量向西流去.速度分布与流函数分布均表明这一支向西的海流大约在冲绳岛西南分为3支,主要分支转向东北沿冲绳岛以东海域向东北流去;(4)琉球海流主要来自上述西向海流.     

赤道太平洋的环流

一.引 言 赤道太平洋上层海洋环流的主要特征已被建立十多年了。1942年斯维尔德鲁普等人描述了中太平洋的表面流:往西流的北和南赤道流以及往东流的北赤道逆流。随后,南赤道逆流也被用表面动力高度图表示出来(Reia,1961),Cromwell等人(1954)发现了赤道潜流,从而对上述环流的描述进行了主要修正。Hisard和Rual(1970)发现了赤道潜流下面     

CMIP5模式对近30年沃克环流强度变化模拟的不足及成因分析 *

太平洋沃克环流(Pacific Walker Circulation, PWC)是热带太平洋上空至关重要的大气环流系统, 但其在全球变暖背景下的长期变化仍存在争议, 换而言之, 沃克环流增强或减弱仍是有待回答的科学问题之一。观测表明近30年PWC呈增强趋势, 而气候模式无法得出观测的趋势。文章分析了参加第五次耦合模式比较计划(Coupled Model Inter-comparison Project Phase 5, CMIP5)的18个耦合模式模拟的PWC变化。结果表明, 大部分耦合模式能够较好地再现PWC的气候态分布特征, 但不能给出其加强的趋势。究其原因, 主要取决于模式对海表温度(SST)变化的模拟能力, 能模拟出PWC加强的耦合模式, 其模拟的SST趋势分布与观测相近[即类拉尼娜(La Niña)型], 但仍存在一定差异; 而模拟出PWC减弱的耦合模式, 其模拟的SST趋势分布表现为类厄尔尼诺(El Niño)型, 这与观测不符。对于后者, 如果用观测的SST驱动其大气模式却能够模拟出PWC的加强, 从另一方面也说明了SST变化对于PWC长期变化的主导作用。因此, CMIP5模式要想合理地预估PWC在全球变暖背景下的变化, 需要提高对于热带太平洋SST变化的模拟能力。     

近几十年来珠江三角洲网河水位时空变化及原因初探

根据珠江三角洲网河区25站的验潮序列,应用功率谱分析和正、反傅氏变换方法对网河区月均水位序列的周期变化和趋势变化进行研究,探讨大规模人类采砂活动对珠江三角洲网河区近几十年来水位变化的影响。结果表明:水位序列中包含0.2~11.7 a多尺度的显著周期波动;应用正、反傅氏变换方法消除月均序列中的短周期波动(消除6 a以短的周期),由低通序列进行一元线性回归分析确定水位变化率,变化率从－3.8到3.7 mm/a不等,珠江三角洲网河区水位总体呈上升趋势。从网河区上段到下段再到口门,水位变化趋势由下降转为上升;变化率由负转正,并逐渐增大。网河区上段部分验潮站水位下降主要与西北江网河上段大规模无序采砂引起的河床大幅人为下切有关;大规模采砂导致局部水位下降,使不同时段的水位变化率发生波动,甚至造成部分验潮站的水位变化由缓慢上升转为大幅下降的"逆变"。     

珠江三角洲近几十年水位变化趋势研究

根据珠江三角洲20个验潮站近几十年来的验潮资料,应用最平滤波器对月均验潮序列进行低通数字滤波,由低通序列一元线性回归分析确定各站的水位变化趋势。应用经验正交函数（EOF）对区域水位变化进行分解,由分解的特征函数来分析区域水位变化的时一空特征,据主要模态的时间特征函数,计算区域水位的平均变化趋势。EOF分解表明,珠江三角洲水位总体呈上升趋势,平均变化率为3.1mm·a-1。     

珠江三角洲近几十年水位变化趋势研究

根据珠江三角洲２０个验潮站近几十年来的验潮资料,应用最平滤波器对月均验潮序列进行低通数字滤波,由低通序列一元线性回归分析确定各站的水位变化趋势。应用经验正交函数（ＥＯＦ）对区域水位变化进行分解,由分解的特征函数来分析区域水位变化的时－空特征,据主要模态的时间特征函数,计算区域水位的平均变化趋势。ＥＯＦ分解表明,珠江三角洲水位总体呈上升趋势,平均变化率为３．１ｍｍ·ａ＾－１。     

Intermediate Circulation in the Northwestern North Pacific Derived from Subsurface Floats

In order to examine the formation, distribution and synoptic scale circulation structure of North Pacific Intermediate Water (NPIW), 21 subsurface floats were deployed in the sea east of Japan. A Eulerian image of the intermediate layer (density range: 26.6–27.0σ_θ) circulation in the northwestern North Pacific was obtained by the combined analysis of the movements of the subsurface floats in the period from May 1998 to November 2002 and historical hydrographic observations. The intermediate flow field derived from the floats showed stronger flow speeds in general than that of geostrophic flow field calculated from historical hydrographic observations. In the intermediate layer, 8 Sv (1 Sv ≡ 10⁶ m³s⁻¹) Oyashio and Kuroshio waters are found flowing into the sea east of Japan. Three strong eastward flows are seen in the region from 150°E to 170°E, the first two flows are considered as the Subarctic Current and the Kuroshio Extension or the North Pacific Current. Both volume transports are estimated as 5.5 Sv. The third one flows along the Subarctic Boundary with a volume transport of 5 Sv. Water mass analysis indicates that the intermediate flow of the Subarctic Current consists of 4 Sv Oyashio water and 1.5 Sv Kuroshio water. The intermediate North Pacific Current consists of 2 Sv Oyashio water and 3.5 Sv Kuroshio water. The intermediate flow along the Subarctic Boundary contains 2 Sv Oyashio water and 3 Sv Kuroshio water. This revised version was published online in July 2006 with corrections to the Cover Date.     

西中太平洋经向大气环流的年际变化

讨论了西中太平洋经向大气环流的年际变化特征,其中西太平洋区(WP)和中太平洋区(CP)EOF分解的第一模态分别是WP的负异常Hadley环流和CP的正异常Hadley环流,其时间系数与Nio3.4指数极为一致;第二模态的最显著空间特征是两区都在5°N~15°N有异常上升,但其时间系数与Nio3.4指数同期相关很低。西中太平洋有2类海表面温度异常(SSTa),通过其上的深对流潜热加热驱动异常Hadley环流:El Nio型驱动了WP区和CP区赤道区符号相反的第一模态异常环流型;热带辐合带(ITCZ)型驱动了WP区和CP区5°N~15°N区符号一致的第二模态异常环流。     

磨刀门河口近期水文动力变化及人类活动对其影响研究

分析磨刀门河口近几十年来水文动力的变化并重点研究围垦和挖沙这二类人类活动对水文动力变化的影响。磨刀门河口近期水文动力的变化主要表现在:水位升高,主干分流比加大,断面平均流速增大;潮汐动力20世纪607、0年代至90年代初明显减弱,潮差减小,主要分潮振幅变小;20世纪90年代初至21世纪初,潮汐动力增强,潮差增大,主要分潮振幅变大,涨潮量增大。围垦加速了水位的抬升,改变了河口的径流和涨潮量分流比,使河口的断面平均流速增大,减弱了河口的潮汐动力。挖沙使河口潮汐动力增强,降低了水位上升的速度。     

Wave climate variability in the North Atlantic in recent decades in the winter period using numerical modeling

The study focuses on investigating significant wave height, including both mean and extreme values, in the North Atlantic in winter during the period from 1979 to 2010. We perform a 32-year wind wave hindcast for the North Atlantic using a spectral ocean wave model (WaveWatch III) and a high-resolution nonhydrostatic atmospheric model (WRF-ARW), which provides the wind forcing function. Analysis of the 32-year hindcast of wave characteristics in the North Atlantic reveals stronger mean and extreme waves simulated with high resolution modeling systems and identifies significant downward trends in the mean significant wave height in the subpolar North Atlantic. Such trends were not found in the wave characteristics from ERA-Interim reanalysis. At the same time, the 32-year hindcast did not confirm the statistically significance of strong positive trends in the central Atlantic diagnosed by ERA-Interim reanalysis; differences between the reanalysis and hindcast are discussed.     

Increase of anthropogenic CO2 in the Pacific Ocean over the last two decades

The multiple-parameter linear regression method (Monitoring global ocean carbon inventories. Ocean Observing System Development Panel, Texas A&M University, College Station, TX, 1995, 54pp; Global Biogeochem. Cycles 13 (1999) 179) is used to compare inorganic carbon data from the GEOSECS CO₂ survey in the Pacific Ocean in 1973 to the WOCE/JGOFS global CO₂ survey in the 1990s. A model of total dissolved inorganic carbon (DIC) as a function of five variables (AOU, θ, S, Si, and PO₄) has been developed from the recent CO₂ survey data (namely CGC91 and CGC96) in the Pacific Ocean. After correcting for a systematic DIC offset of −30.3±7 μmol kg⁻¹ from the GEOSECS data, the residual DIC based on this model as computed from GEOSECS data has been used to estimate the anthropogenic CO₂ penetration in the Pacific Ocean. In the Northeast Pacific, we obtained an increase of CO₂ of 21.3±7.9 mol m⁻² over the period from GEOSECS in 1973 to CGC91 in 1991. This gives a mean anthropogenic CO₂ uptake rate of 1.3±0.5 mol m⁻² yr⁻¹ over this 17 year time period. In the South Pacific, north of 50°S between 180° and 120°W region, the integrated anthropogenic CO₂ inventory is estimated to be 19.7±5.7 mol m⁻² over the period from GEOSECS in 1974 to CGC96 in 1996. The equivalent mean CO₂ uptake rate is estimated to be 0.9±0.3 mol m⁻² yr⁻¹ over the 22 years. These results are compared with the isopycnal method (Nature 396 (1998) 560) to estimate the anthropogenic CO₂ signal in the Northeast Pacific (30°N, 152°W) at the crossover region between CGC91 and GEOSECS. The results of the isopycnal method are consistent with those derived from the MLR method. Both methods show an increase in anthropogenic CO₂ inventory in the ocean over two decades that is consistent with the increase expected if the ocean uptake has kept pace with the atmospheric CO₂ increase.     

中国大陆海岸线近30 a的时空变化分析

基于遥感和地理信息系统的方法与技术,以1980、1990、2000和2010年4个时期为特征年,对近30年来我国大陆海岸线时空变化特征进行了分析研究。结果显示:（1）海岸类型转化显著,人工岸线所占比例由1980年的24.6%上升到2010年的56.1%;（2）海岸线变化呈现显著区域特征,变化较剧烈的区域集中在珠江口岸段、长江口-杭州湾岸段、海州湾-吕四段、滦河口-潍河口段及辽河口-葫芦岛港段;（3）3个时期相比,海岸开发由早期的围垦养殖向后期的城镇建设和海洋运输开发方式转变,并且这种转换方式在南方早于北方。     

The seasonal variation of the North Pacific Meridional Overturning Circulation heat transport

Based on the 50-year Simple Ocean Data Assimilation (SODA) reanalysis data, we investigated the basic characteristics and seasonal changes of the meridional heat transport carried by the North Pacific Meridional Overturning Circulation. And we also examined the dynamical and thermodynamic mechanisms responsible for these heat transport variability at the seasonal time scale. Among four cells, the tropical cell (TC) is strongest with a northward heat transport (NHT) of (1.75±0.30) PW (1 PW=1.0×10^15 W) and a southward heat transport (SHT) of (-1.69±0.55) PW, the subtropical cell (STC) is second with a NHT of (0.71±0.65) PW and SHT of (-0.63±0.53) PW, the deep tropical cell (DTC) is third with a NHT of (0.18±0.03) PW and SHT of (-0.18±0.11) PW, while the subpolar cell (SPC) is weakest with a NHT of (0.09±0.05) PW and SHT of (-0.07±0.09) PW. These four cells all have diff erent seasonal changes in their NHT and SHT. Of all, the TC has stronger change in its SHT than in its NHT, so do both the DTC and SPC, but the seasonal change in the STC SHT is weaker than that in its NHT. Therefore, their dynamical and thermodynamic mechanisms are diff erent each other. The local zonal wind stress and net surface heat flux are mainly responsible for the seasonal changes in the TC and STC NHTs and SPC SHT, while the local thermocline circulations and sea temperature are primarily responsible for the seasonal changes of the TC, STC and DTC SHTs and SPC NHT.