Model of the Tropical Atlantic incorporating the upper mixed layer

We present a multilayer ocean model incorporating a non-local integral model of the upper mixed layer (UML). In the framework of a three-layer Tropical Atlantic model, we study the model's response to various closure hypotheses for heat fluxes at the UML lower boundary.Translated by V. Puchkin.     

Modelling of upwelling and downwelling in the ocean

Numerical experiments on the reconstruction of upwelling and downwelling at the eastern boundary of the ocean were carried out in the framework of a multilayer model of the ocean involving the upper mixed layer (UML). The peculiarities of these phenomena when they are formed and attenuated owing to the strong intensification and abatement of the longshore wind have been studied. It is shown that cold waters are always involved from the thermocline to the UML during upwelling. In downwelling, this occurs as a rule. However, during upwelling the abatement of the wind may result in subduction —the inflow of warm waters from the UML to the thermocline.Translated by Mikhail M. Trufanov.     

A hydrothermodynamic quasi-isopycnic model of the ocean thermocline

The results of a numerical experiment on the formation of the large-scale circulation and the main thermocline in the temperate latitudes of an ocean at steady external factors are discussed. A multilayer model [1] is used which involves the upper mixed layer (UML). The boundaries of the areas where the internal layers reach the UML are calculated. The zones where seawater is entrapped from the thermocline to the UML are revealed, as well as the subduction zones where seawater is brought from the UML to the internal layers and moves there, ventilating the thermocline.Translated by Mikhail M. Trufanov. UDK 551.465.     

一种基于工作流逻辑偶的海域无人机监视监测业务流程建模方法

通过构建海域无人机监视监测业务流程形式化模型,为海域无人机监控与管理系统能够自适应可变的业务流程奠定基础。首先对比了各种业务流程建模方法的技术特点和适用场景,然后对海域无人机监视监测业务流程进行分析,提出了一种UML活动图转化为基于Petri网的工作流逻辑偶的方法,最后基于此方法对海域无人机监视监测业务流程进行建模。建模结果表明,该方法能有效地将海域无人机监视监测业务流程的分支、分叉以及汇合等流程逻辑转化为工作流逻辑偶,并且转化的结果满足良序性、良构性以及畅通性。     

Quasi-isopycnic layer model for large-scale ocean circulation

A hydrothermodynamic model of a multilayer ocean, incorporating the upper mixed layer (UML) is described. The model is based on a system of primitive equations integrated within each layer. All layers are assumed to be horizontally-inhomogeneous, however, the density in each thermocline layer changes within the limits determineda priori by the prescribed basic stratification. It is assumed that the layers may outcrop. Results of the numerical experiment on subduction simulation (downwelling of UML waters toward the main thermocline layers) are given.Translated by V. Puchkin.     

支持海洋遥感信息提取技术的可视化建模系统流程设计

根据海洋遥感信息提取可视化建模应用需求,以用户可视化模型建立及流程设计实现为目标,采用统一建模语言UML面向对象分析方法,设计海洋遥感信息提取可视化建模系统软件结构、用户需求用例(use case)结构、类(class)结构及流程图表示法,同时完成流程定义器、流程调度的设计和实现.结果表明,可视化用户建模系统可以使广大海洋用户在使用遥感数据时无须在数据预处理及转换工作上花费较多的时间,也不要学习很多遥感信息处理专业知识即可适应和使用组件式海洋遥感数据处理和信息提取通用软件,并且在该软件平台上进行他们的研究和应用开发工作.     

Evaluation of the heat balance constituents of the upper mixed layer in the North Atlantic

Different physical mechanisms which cause interannual and interdecadal temperature anomalies in the upper mixed layer (UML) of the North Atlantic are investigated using the data of ORA-S3 reanalysis for the period of 1959–2011. It is shown that the annual mean heat budget in UML is mainly caused by the balance between advective heat transfer and horizontal turbulent mixing (estimated as a residual term in the equation of thermal balance). The local UML temperature change and contribution from the heat fluxes on the lower boundary of the UML to the heat budget of the upper layer are insignificant for the time scale under consideration. The contribution of the heat fluxes on the upper UML boundary to the low-frequency variability of the upper layer temperature in the whole North Atlantic area is substantially less than 30%. Areas like the northwestern part of the Northern Subtropical Anticyclonic Gyre (NSAG), where their contribution exceeds 30–60%, are exceptions. The typical time scales of advective heat transfer variability are revealed. In the NSAG area, an interannual variability associated with the North Atlantic Oscillation dominates, while in the North Atlantic subpolar gyre, an interdecadal variability of advective transfers with periods of more than 30 years prevails.     

有限海域海水表温数值预报改进模式

以海洋上部混合层(UML)存在为基础,建立了考虑UML深度变化的二维层模式。探讨有限区域的短期海表温(SST)业务数值预报模式。预报方程有三:低频流(黑潮及其分支)的无幅散化余流方程组、动力预报方程和模式物理学方程。本模式用于3～5d的SST预报,同时也给出UML平均漂流的预报。指出在大风状况下的降温,UML深是一个重要的影响因子,并与UML为平底时情况进行了比较。     

Modelling of the generation and evolution of the cold intermediate layer in the Black Sea

This paper discusses the results of a numerical experiment on modelling the seasonal variability of the water circulation and temperature/salinity fields in the Black Sea. A multi-layered quasi-isopycnic model is used based on primitive equations and incorporating the upper mixed layer (UML). It is shown that during springtime warming, relatively cold layers emerge in some areas, due to subduction, from the UML, which then spread virtually over the entire basin and persist until they become absorbed by the rapidly deepening UML during the period of cooling in winter. Translated by Vladimir A. Puchkin.     

A quantitative analysis of sources for summertime phytoplankton variability over 18 years in the South Shetland Islands (Antarctica) region

Eighteen years of summertime hydrographic and chlorophyll-a (Chl-a) data (～2700 stations) from the South Shetland Islands (Antarctica) region show that a “bell-shaped” (unimodal) distribution of phytoplankton biomass results annually when plotted against the inshore to offshore gradient in surface salinity. The maximum for this unimodal Chl-a distribution corresponds with a shallow upper mixed layer (UML) in iron-rich waters that occurs at salinities ～34. Methods of gradient analysis are used to distinguish sources of variability for bloom development among years. The control of phytoplankton biomass is resolved across the salinity gradient that separates the co-limiting conditions of deep UML depths and low-iron concentrations as opposing end-members. Chlorophyll-fluorescence yield data (a proxy for Fe-stress) showed that at salinities ～34, phytoplankton biomass was unlikely to be limited by Fe. Instead, blooming at salinities ～34 (1.3±1 mg Chl-a m^?3) co-varied with shallow UML depths (41±19 m) that occurred as a function of higher UML temperature (1.5±0.5 °C) among years, and is evidence that atmospheric climate variability impacts summertime phytoplankton biomass and production in this Southern Ocean seascape.     

Observation and modelling of the variability of the Arabian Sea upper layers during the development of the SW monsoon in 1988 and 1989

Experimental data on the vertical structure of theT, S temporal variations in the upper 1000 m layer of the Arabian Sea during the inter-monsoon period from April to June are reported. Variations in the upper mixed layer (UML) thickness and temperature distributed horizontally are considered. The local UML model was used to compute these variations from the atmospheric influence preset from observations.Translated by Mikhail M. Trufanov.     

Short-term photoacclimation effects on photoinhibition of phytoplankton in the Drake Passage (Southern Ocean)

We assessed whether short-term photoacclimation responses of natural phytoplankton populations in the Drake Passage (Southern Ocean) were affecting protection from photodamage as cells are mixed up to the surface from depth. To this end, we measured phytoplankton fluorescence characteristics and their ratio of xanthophyll cycle pigment to photosynthetic pigments within the upper mixed layer (UML) and in short-term deck incubation experiments. Phytoplankton within the UML photoacclimated by increasing their ratio of xanthophyll cycle (diadinoxanthin [dd] and diatoxanthin [dt]) pigments to chlorophyll a. The photoacclimation processes observed within the UML did, however, not influence the protection of phytoplankton from photodamage during short-term near-surface irradiance experiments. Exposure to near-surface irradiance resulted in photodamage in all experiments, regardless of the phytoplankton community composition and irradiance levels. Incubating phytoplankton for six hours at either 2% or 50% of surface irradiance prior to exposure to near-surface irradiance did not alter the photodamage characteristics. This suggests that short-term photoacclimation processes within the UML are not adequate to protect phytoplankton from photodamage when cells are mixed up to the surface from depth, and that repair of damaged photosystems is crucial for maintaining photosynthesis under fluctuating irradiance conditions, even at very low mean irradiance levels. Likely, continuously operating photoacclimation processes offset to some extent the negative effects of photodamage on photosynthetic performance, albeit with increased metabolic costs.     

HF radar ocean current algorithm based on MUSIC and the validation experiments

Wuhan University's ocean state measuring and analyzing radar (OSMAR2000), working at around 7.5 MHz in the low region of the HF band with a 120-m-long linear receiving antenna array, can measure ocean surface current at ranges of up to 200 km. An ocean surface current algorithm based on direction finding (DF) using the multiple signal classification (MUSIC) method is developed for the OSMAR2000 radar. This paper describes the OSMAR2000 ocean surface current algorithm based on MUSIC and the validation experiments in the East China Sea. The results of the ocean surface current measurements demonstrate that the OSMAR2000 ocean surface current algorithm based on MUSIC is feasible for the long range of ocean surface current mapping with a sufficient bearing resolution.     

Connections between the Long-Period Variability Modes of Both Temperature and Depth of the Upper Mixed Layer of the North Atlantic and the Climate Variability Indices

Izvestiya, Atmospheric and Oceanic Physics - The interannual–multidecadal variability of the temperature and depth of the upper mixed layer (UML) in the North Atlantic (NA) is analyzed on the...     

A spectral barotropic model of the wind-driven world ocean

A global spectral barotropic ocean model is introduced to describe the depth-averaged flow. The equations are based on vorticity and divergence (instead of horizontal momentum); continents exert a nearly infinite drag on the fluid. The coding follows that of spectral atmospheric general circulation models using triangular truncation and implicit time integration to provide a first step for seamless coupling to spectral atmospheric global circulation models and an efficient method for filtering of ocean wave dynamics. Five experiments demonstrate the model performance: (i) Bounded by an idealized basin geometry and driven by a zonally uniform wind stress, the ocean circulation shows close similarity with Munk’s analytical solution. (ii) With a real land–sea mask the model is capable of reproducing the spin-up, location and magnitudes of depth-averaged barotropic ocean currents. (iii) The ocean wave-dynamics of equatorial waves, excited by a height perturbation at the equator, shows wave dispersion and reflection at eastern and western coastal boundaries. (iv) The model reproduces propagation times of observed surface gravity waves in the Pacific with real bathymetry. (v) Advection of tracers can be simulated reasonably by the spectral method or a semi-Langrangian transport scheme. This spectral barotropic model may serve as a first step towards an intermediate complexity spectral atmosphere–ocean model for studying atmosphere–ocean interactions in idealized setups and long term climate variability beyond millennia.     

A spectral barotropic model of the wind-driven world ocean

A global spectral barotropic ocean model is introduced to describe the depth-averaged flow. The equations are based on vorticity and divergence (instead of horizontal momentum); continents exert a nearly infinite drag on the fluid. The coding follows that of spectral atmospheric general circulation models using triangular truncation and implicit time integration to provide a first step for seamless coupling to spectral atmospheric global circulation models and an efficient method for filtering of ocean wave dynamics. Five experiments demonstrate the model performance: (i) Bounded by an idealized basin geometry and driven by a zonally uniform wind stress, the ocean circulation shows close similarity with Munk’s analytical solution. (ii) With a real land–sea mask the model is capable of reproducing the spin-up, location and magnitudes of depth-averaged barotropic ocean currents. (iii) The ocean wave-dynamics of equatorial waves, excited by a height perturbation at the equator, shows wave dispersion and reflection at eastern and western coastal boundaries. (iv) The model reproduces propagation times of observed surface gravity waves in the Pacific with real bathymetry. (v) Advection of tracers can be simulated reasonably by the spectral method or a semi-Langrangian transport scheme. This spectral barotropic model may serve as a first step towards an intermediate complexity spectral atmosphere–ocean model for studying atmosphere–ocean interactions in idealized setups and long term climate variability beyond millennia.     

Organic matter characterization and fate in the sub-arctic Norwegian fjords during the late spring/summer period

The organic matter (OM) pool has been studied in two sub-arctic north Norwegian fjords, Balsfjord and Ullsfjord, in July 2001 and June 2003. Besides general OM parameters such as dissolved organic carbon (DOC), particulate organic carbon and nitrogen (POC and PON), the distribution of specific compounds such as folic acid and surface active substances (SAS) was followed. The results are supported with data of salinity, temperature, and chlorophyll a (Chl a). This approach allowed assessment of the fate of the OM pool, and its distinct vertical, spatial, and seasonal variations. Fjord waters could be vertically divided into two layers: the upper mixed layer (UML), until 40 m depth, and the deep aphotic layer. Spatial variability between the two fjords is a consequence of different influences of shelf waters on the fjords. Significant enrichment of POC and PON concentrations (3–5 times), as well as those of particulate SAS and folic acid (up to 3.2 times) in the UML was recorded during the period of new production, in early June. Depletion of particulate OM in deep waters was ascribed to fast dissolution or remineralization in the UML or upper part of aphotic layer. OM in July 2001 was characterized with 15.9% higher DOC pool compared to June 2003, and had refractory properties, suggesting the fjords to be an important source of organic matter for the continental shelf ecosystem. The DOC pool in these subarctic fjords represents the major component of the OM pool. The DOC concentrations in fjords are lower than those in previously studied warmer seas (e.g. the Adriatic Sea), whereas the concentrations of folic acid and SAS are comparable to those in the Adriatic Sea.     

Application of leeway drift data to predict the drift of panga skiffs: Case study of maritime search and rescue in the tropical pacific

The use of Search and Rescue (SAR) drift forecasting in an operational capacity is demonstrated through two SAR case studies, each predicting the drift of a panga skiff for 120 h (Case 1) and 72 h (Case 2). The leeway characteristics of panga skiffs were previously unknown, until a leeway field study was undertaken in mid-2012 to empirically determine the influence of wind and waves on their drift. As part of the two case studies described herein, four ocean models were used as environmental forcing for a stochastic particle trajectory model, to forecast the drift and resulting search areas for the panga skiffs. Each of the four ocean models were tested individually, and then combined into a consensus forecast to ascertain which ocean model was the most accurate in terms of distance error of modelled positions compared to actual panga skiff locations. Additionally, a hit analysis was undertaken to determine whether the panga skiff was located within the forecast search areas for each ocean model, and for consensus search areas. Finally, an assessment of the search area sizes was carried out to assess the single ocean model forecast search area sizes, and how they compared with the consensus search area size. In both of the case studies, all four ocean model forecast search areas contained the panga skiff at the time intervals tested, indicating a 100% hit rate and general consensus between the ocean models. The consensus search area, where all four ocean models overlapped, was approximately one third the size of the average single model search area. This demonstrates that the consensus search areas provide a more efficient search area compared to individual ocean model search area forecasts.     

The effect of the wave-induced mixing on the upper ocean temperature in a climate model

The significant underestimation of sea surface temperature （SST） and the temperature in the upper ocean is one of common problems in present climate models. The influence of the wave-induced mixing on SST and the temperature in the upper ocean was examined based on a global climate model. The results from the model coupled with wave-induced mixing showed a significant improvement in the simulation of SST and the temperature in the upper ocean compared with those of the original model without wave effects. Although there has still a cold bias, the new simulation is much closer to the climatology, especially in the northern ocean and tropical ocean. This study indicates that some important physical processes in the accurate simulation of the ocean may be ignored in present climate models, and the wave-induced mixing is one of those factors. Thus, the wave-induced mixing （ or the effect of surface waves） should be incorporated properly into climate models in order to simulate or forecast the ocean, then climate system, more accurately.     

基于“灰箱”模型的海洋公共治理责任结构论证分析

海洋公共治理是我国政府治理现代化体系建设的重要组成内容。作为适应新时期"海洋强国"战略实施的海洋公共治理被认作一种异于传统陆地政府治理的新型地公共治理活动,存在着自身一定的责任结构体系。收集了2012-2016年的六大类海洋责任案例(主要是海洋执法案例),以时间(t)、案例数量(q)、制度(I)、人(H)来构建"灰箱"模型,通过考察问责复发率(P)分析海洋公共责任(R)的问题及原因。研究结果表明:(1)我国海洋公共治理过程中应亟须重视"海洋政府"理念,问责事件也从样本数量上得到了体现;(2)海洋公共治理的目标应是防范于未然,确保责任事件的可预期化,推进政府治理能力现代化,应当基于法治的导向来重新塑造海洋政府的责任体系;(3)我国未来海洋公共治理的责任体系建构应通过立法的方式实现责任人和责任形式的可预期化,最终实现对海洋公共治理责任法治监督的应有之义。