Observed spatiotemporal variation of three-dimensional structure and heat/salt transport of anticyclonic mesoscale eddy in Northwest Pacific

Journal of Oceanology and Limnology - As in-situ observations are sparse, targeted observations of a specific mesoscale eddy are rare. Therefore, it is difficult to study the three-dimensional...     

基于SODA资料的太平洋及我国周边海域温差能资源时空特征分析

基于简单海洋数据同化数据集的逐月再分析海温资料,对1971年1月至2010年12月共40年的太平洋及我国周边海域温差能资源的时空特征进行统计分析,得到以下主要结论:（1）温差季节变化特征明显,北半球的20℃等温差线从冬季到夏季可由20°N扩展到40°N,而南半球的温差受季节变化相对较小;温差能有效开采区域集中在30°S~40°N范围内,但纬向分布不均;可近似将气候态平均的20℃等温差线作为全年可开采区域的边界;（2）太平洋绝大部分海域的温差能等价深度呈逐年上升趋势,最大可达近2 m/a;温差能的变异系数具有明显季节变化特征但总体维持在较低水平,有效开采区域之内的变异系数在各季节均低于0.1;（3）我国温差能资源在南海及台湾以东海域最为丰富,其温差维持较高水平,能量密度总体呈逐年上升趋势,能量的稳定性较好且可实现全年有效开采,其最佳利用时间为5-7月,最差利用时间为2-3月;（4）太平洋温差能储量在TW量级,且以2.83 GW/a的趋势递增。     

Evaluating the contribution of satellite measurements to the re-construction of three-dimensional ocean temperature fields in combination with Argo profiles

Assimilation systems absorb both satellite measurements and Argo observations. This assimilation is essential to diagnose and evaluate the contribution from each type of data to the reconstructed analysis, allowing for better configuration of assimilation parameters. To achieve this, two comparative reconstruction schemes were designed under the optimal interpolation framework. Using a static scheme, an in situ-only field of ocean temperature was derived by correcting climatology with only Argo ...     

台湾以东表面黑潮流量与涡旋场相互作用研究

本文基于法国空间局AVISO中心提供的1993年~2015年的卫星遥感海面高度和海表流场逐日资料,分析了台湾以东表面黑潮流量及其邻近海域的涡旋场（海面高度异常）,得到了台湾以东表面黑潮流量和涡旋场的四个主要周期,并研究了不同对应周期的黑潮表面流量及其邻近涡旋场之间的相互作用关系。论文主要结论如下：（1）基于小波分析法,分析了台湾以东表面黑潮流量及其邻近的涡旋场,发现两者都具有明显的季节、年和年际变化周期。对于表面黑潮流量,除了具有182天（0.5年）和365天（1年）的显著周期外,还存在860天（2.35年）和2472天（6.8年）左右的较为明显的周期。涡旋场也相应地存在200天（0.55年）、374天（1年）、889天（2.43年）和2374天（6.5年）四个较明显的周期,但在不同的纬度存在一定差异;（2）基于相关分析和因果分析法,分析了以上四个周期内表面黑潮流量及其邻近涡旋场的相关性,揭示了黑潮与涡旋在不同周期区间、不同纬度相互影响关系的差异。     

Some progress on ocean data assimilation in China: Introduction of the special section “Ocean Data Assimilation”

<正>This special section is the scientific legacy of the 13th National Ocean Data Assimilation and Numerical Simulation Conference of China, which was held in Changsha, China during December 3–4, 2020 with more than 160 participants from 35 units in China. It continued a series of National Ocean Data Assimilation conferences which began in 2003,     

An analysis on the error structure and mechanism of soil moisture and ocean salinity remotely sensed sea surface salinity products

For the application of soil moisture and ocean salinity（SMOS） remotely sensed sea surface salinity（SSS） products,SMOS SSS global maps and error characteristics have been investigated based on quality control information.The results show that the errors of SMOS SSS products are distributed zonally,i.e.,relatively small in the tropical oceans,but much greater in the southern oceans in the Southern Hemisphere（negative bias） and along the southern,northern and some other oceanic margins（positive or negative bias）.The physical elements responsible for these errors include wind,temperature,and coastal terrain and so on.Errors in the southern oceans are due to the bias in an SSS retrieval algorithm caused by the coexisting high wind speed and low temperature; errors along the oceanic margins are due to the bias in a brightness temperature（TB） reconstruction caused by the high contrast between L-band emissivities from ice or land and from ocean; in addition,some other systematic errors are due to the bias in TB observation caused by a radio frequency interference and a radiometer receivers drift,etc.The findings will contribute to the scientific correction and appropriate application of the SMOS SSS products.     

Effects of Na^＋/K^＋ Ratio of Groundwaters on the Gill Ion-Transport Enzyme Activity, Plasma Osmolality and Growth of Cynoglossus semilaevis Juveniles

The effects of environmental Na /K ratio on the gill ion-transport enzyme activity,plasma osmolality and growth ofCynoglossus semi/aevis juveniles were investigated.The results showed that,plasma osmolality was similar among flounder adaptedto different Na /K ratios of saline groundwaters (P>0.05),while the growth,gill Na ,K -ATPase and HCO,3'--ATPase activities wereaffected by Na /K ratio significantly (P<0.05).The gill Na ,K -ATPase activity reached its maximum on day 3,then decreasedgradually from day 3 to day 9 and remained constant from day 9 to day 15.The peak values of gill Na ,K -ATPase activity weredetected on day 3 for all Na /K ratios of saline groundwaters,then the enzyme activities descended,and on day 9 the enzyme activi-ties achieved steady state,and the gill HCO,3--ATPase activity increased rapidly and achieved steady state after one day.Duringsteady state,the gill Na ,K -ATPase and HCO,3--ATPase activity of Na /K ratios 20 and 40 treatments were significantly higherthan those in the control group (Na /K ratio 27.5),while there were no significant differences between the Na /K ratio 30 treatmentand the control group; the gill Na ,K -ATPase activity of Na /K ratio 20 and 40 treatments were significantly higher than that forratio 30 treatment,but there were no significant differences of gill HCO3-ATPase activity among these treatments.At the end of the15-day experiment,the weight gain (%) and specific growth rate (SGR) of flounders maintained in seawater were significantly higherthan those in groundwaters; significant differences also occurred among the treatments; Na /K ratio 30 treatment had the highestvalues (33.7% and 1.94 respectively),which were significantly higher than those under Na /K ratios 20 and 40 treatments.There-fore,for the saline groundwater used in this experiment,it is suggested that the Na /K ratio be adjusted to approximately 30,I.e.,asclose to that of natural seawater as possible in the culture of flounder.     

Effects of Na+/K+ ratio of groundwaters on the gill ion-transport enzyme activity, plasma osmolality and growth of Cynoglossus semilaevis juveniles

The effects of environmental Na⁺/K⁺ ratio on the gill ion-transport enzyme activity, plasma osmolality and growth of Cynoglossus semilaevis juveniles were investigated. The results showed that, plasma osmolality was similar among flounder adapted to different Na⁺/K⁺ ratios of saline groundwaters (P>0.05), while the growth, gill Na⁺, K⁺-ATPase and HCO₃ ⁻-ATPase activities were affected by Na⁺/K⁺ ratio significantly (P<0.05). The gill Na⁺, K⁺-ATPase activity reached its maximum on day 3, then decreased gradually from day 3 to day 9 and remained constant from day 9 to day 15. The peak values of gill Na⁺, K⁺-ATPase activity were detected on day 3 for all Na⁺/K⁺ ratios of saline groundwaters, then the enzyme activities descended, and on day 9 the enzyme activities achieved steady state, and the gill HCO₃ ⁻-ATPase activity increased rapidly and achieved steady state after one day. During steady state, the gill Na⁺, K⁺-ATPase and HCO₃ ⁻-ATPase activity of Na⁺/K⁺ ratios 20 and 40 treatments were significantly higher than those in the control group (Na⁺/K⁺ ratio 27.5), while there were no significant differences between the Na⁺/K⁺ ratio 30 treatment and the control group; the gill Na⁺, K⁺-ATPase activity of Na⁺/K⁺ ratio 20 and 40 treatments were significantly higher than that for ratio 30 treatment, but there were no significant differences of gill HCO₃ ⁻-ATPase activity among these treatments. At the end of the 15-day experiment, the weight gain (%) and specific growth rate (SGR) of flounders maintained in seawater were significantly higher than those in groundwaters; significant differences also occurred among the treatments; Na⁺/K⁺ ratio 30 treatment had the highest values (33.7% and 1.94 respectively), which were significantly higher than those under Na⁺/K⁺ ratios 20 and 40 treatments. Therefore, for the saline groundwater used in this experiment, it is suggested that the Na⁺/K⁺ ratio be adjusted to approximately 30, i.e., as close to that of natural seawater as possible in the culture of flounder.     

基于最小二乘支持向量机的副热带高压预测模型

采用EOF时空分解、小波频牢分解和最小二乘支持向量机（LS-SVM）交叉互补方法,建立夏季500 hPa位势高度场的预测模型,用以描绘和表述副热带高压形势场的形态和变化。首先用经验正交函数分解（EOF）方法将NCEP/NCAR再分析资料500 hPa位势高度场序列分解为彼此正交的特征向量及其对应时间系数,随后提取前15个主要特征向龟的时间系数（方差贡献96.2%）,采用小波分解方法将其分解为相对简单的带通信号,再利用LS-SVM方法建立各分量信号的预测模型,最后通过小波时频分量重构和EOF时空重构,得到500hPa位势高度场的预测结果以及副热带高压形势场的预测。通过对预测模型的试验情况和分析对比,结果表明:基于上述思想提出的算法模型能较为准确地描述500 hPa位势高度场的形态分布并预测1~7 d的副热带高压活动,对10~15 d的副热带高压活动预测结果也有参考意义。     

Three-dimensional structure of an observed cyclonic mesoscale eddy in the Northwest Pacific and its assimilation experiment

Mesoscale eddies play an important role in modulating the ocean circulation. Many previous studies on the threedimensional structure of mesoscale eddies were mainly based on composite analysis, and there are few targeted observations for individual eddies. A cyclonic eddy surveyed during an oceanographic cruise in the Northwest Pacific Ocean is investigated in this study. The three-dimensional structure of this cyclonic eddy is revealed by observations and simulated by the four-dimensional variational data assimilation(4 DVAR) system combined with the Regional Ocean Modeling System. The observation and assimilation results together present the characteristics of the cyclonic eddy. The cold eddy has an obvious dual-core structure of temperature anomaly.One core is at 50–150 m and another is at 300–550 m, which both have the average temperature anomaly of approximately-3.5°C. The salinity anomaly core is between 250 m and 500 m, which is approximately-0.3. The horizontal velocity structure is axis-asymmetric and it is enhanced on the eastern side of the cold eddy. In the assimilation experiment, sea level anomaly, sea surface temperature, and in situ measurements are assimilated into the system, and the results of assimilation are close to the observations. Based on the high-resolution assimilation output results, the study also diagnoses the vertical velocity in the mesoscale eddy, which reaches the maximum of approximately 10 m/d. The larger vertical velocity is found to be distributed in the range of 0.5 to 1 time of the normalized radius of the eddy. The validation of the simulation result shows that the 4 DVAR method is effective to reconstruct the three-dimensional structure of mesoscale eddy and the research is an application to study the mesoscale eddy in the Northwest Pacific by combining observation and assimilation methods.