Twenty years of ocean observations with China Argo

The international Argo program,a global observational array of nearly 4000 autonomous profiling floats initiated in the late 1990s,which measures the water temperature and salinity of the upper 2000 m of the global ocean,has revolutionized oceanography.It has been recognized one of the most successful ocean observation systems in the world.Today,the proposed decade action“OneArgo”for building an integrated global,full-depth,and multidisciplinary ocean observing array for beyond 2020 has been endorsed.In the past two decades since 2002,with more than 500 Argo deployments and 80 operational floats currently,China has become an important partner of the Argo program.Two DACs have been established to process the data reported from all Chinese floats and deliver these data to the GDACs in real time,adhering to the unified quality control procedures proposed by the Argo Data Management Team.Several Argo products have been developed and released,allowing accurate estimations of global ocean warming,sea level change and the hydrological cycle,at interannual to decadal scales.In addition,Deep and BGC-Argo floats have been deployed,and time series observations from these floats have proven to be extremely useful,particularly in the analysis of synoptic-scale to decadal-scale dynamics.The future aim of China Argo is to build and maintain a regional Argo fleet comprising approximately 400 floats in the northwestern Pacific,South China Sea,and Indian Ocean,accounting for 9%of the global fleet,in addition to maintaining 300 Deep Argo floats in the global ocean(25%of the global Deep Argo fleet).A regional BGC-Argo array in the western Pacific also needs to be established and maintained.

China Argo project:progress in China Argo ocean observations and data applications

This paper reviews the current achievements of the China Argo project. It considers aspects of both the construction of the Argo observing array, float technology, and the quality control and sharing of its data. The developments of associated data products and data applications for use in the fields of ocean, atmosphere, and climate research are discussed, particularly those related to tropical cyclones （typhoons）, ocean circulation, mesoscale eddies, turbulence, oceanic heat/salt storage and transportation, water masses, and operational oceanic/atmospheric/climatic forecasts and predictions. Finaliy, the challenges and opportunities involved in the long-term maintenance and sustained development of the China Argo ocean observation network are outlined. Discussion also focuses on the necessity for increasing the number of floats in the Indian Ocean and for expanding the regional Argo observation network in the South China Sea, together with the importance of promoting the use of Argo data by the maritime countries of Southeast Asia and India.

Ocean Observation Technologies:A Review

Covering about three quarters of the surface area of the earth,the ocean is a critical source of sustenance,medicine,and commerce.However,such vast expanse in both surface area and depth,presents myriad observing challenges for researchers,such as corrosion,attenuation of electromagnetic waves,and high pressure.Ocean observation technologies are progressing from the conventional single node,static and short-term modalities to multiple nodes,dynamic and long-term modalities,to increase the density of both temporal and spatial samplings.Although people’s knowledge of the oceans has been still quite limited,the contributions of many nations cooperating to develop the Global Ocean Observing System(GOOS)have remarkably promoted the development of ocean observing technologies.This paper reviews the typical observing technologies deployed from the sea surface to the seafloor,and discusses the future trend of the ocean observation systems with the docking technology and sustained ocean energy.

Ocean Observation from Haiyang Satellites

In 2018,China successfully launched three new Haiyang(which means ocean in Chinese,referred to as HY)satellites which are an ocean color observation satellite HY-1C(operational),an ocean dynamics environment satellite HY-2B(operational)and the China-France ocean satellite CFOSAT(experimental).In 2019,all the three satellites had finished their commissioning phases and were declared operational.HY-2A satellite continues to operate in-orbit,and its operational status is basically normal.So in 2020,China has 4 Haiyang satellites in-orbit,China’s ocean satellites enter into a new operational application phase.The operation of the ground application system of Chinese ocean satellites is stable.In 2019,Beijing,Hainan,Mudanjiang,and Hangzhou ocean satellite ground stations had received the data of HY-1C,HY-2A,HY-2B,and CFOSAT 5012 orbits and 26.46 TB data had been distributed to both domestic and international users.Chinese ocean satellite data has played an important role in marine disaster prevention and mitigation,development and management of marine resources,maintenance of marine rights and interests,marine environment protection,scientific researches,and blue economy development.

Quality control for ocean observations: From present to future

The quality control(QC) of ocean observational data, essential to establish a high-quality global ocean database, is one of the basic data pre-processing steps in oceanography research, marine monitoring, and forecasting. With the introduction of various advanced instruments in recent decades, oceanographic surveys have expanded from coastal regions to open oceans.However, as ocean in-situ observations are obtained using different instruments that offer heterogeneous data qualities, it is paramount that bad data could be accurately and efficiently identified via QC to provide a reliable global ocean database. In this review, we briefly summarize the latest progress of QC for oceanic in-situ observations, and mainly focus on temperature and salinity data. The similarities and differences between QC schemes developed by various ocean organizations are introduced. We also discuss the performances of the various QC schemes and identify the key challenges. Based on the discussions, several recommendations are proposed for future improvements in the QC for ocean observations.

The SOOS Asian Workshop on Southern Ocean research and observations

1 Background and purpose of workshop The Southern Ocean plays a fundamental role in the function of the Earth System, influencing climate, sea level, biogeochemical cycles, and biological productivity on a variety of scalesIll. Observations from the Southern Ocean suggest that dramatic changes are taking place, which are of global concern, yet because of its remote location, seasonal sea ice, and harsh environment, the Southern Ocean remains one of the least sampled zones in the world.

Digital Ocean Information Framework of China and its application in the international marine cooperation

Digital Ocean Information Framework （DOIF） has been proposed by China in 2011 based on the achievements of the comprehensive offshore oceanic surveys supported by Chinese Offshore Investigation and Assessment Program, whose code name is 908. All observations from the surveys have been integrated and managed by DOIF. DOIF is capable of supporting the decision of making process for the sustainable use of marine resources in coastal regions of China, providing useful information and added value products as well as services for the improved management of the coastal areas in China with high business impact on the targeted groups as public authorities and commercial operators （e.g. managers, fishermen, shipping companies）. The future vision of DOIF in the international marine data and information exchange and service at Western Pacific region is presented in this paper.

Analysis of the characteristics of offshore currents in the Changjiang(Yangtze River) estuarine waters based on buoy observations

A buoy of 10 m in diameter was used to record the current speed and direction in a vertical profile in the offshore area of the Changjiang（Yangtze River） Estuary（with an average water depth of 46.0 m） for one year.The results include：（1） the currents rotate clockwise and the current direction is consistent in a vertical profile without clear seasonal variations.（2） The horizontal current speeds are generally high,with a maximum of 128.5 cm/s occurring in summer and 105.5 cm/s appearing in winter commonly close to the surface.The average current speeds in the vertical profile fall in the same range（the differences are less than 8.0 cm/s）,with the maximum of47.0 cm/s occurring in summer and 40.8 cm/s in winter.The average current speed during spring tides is twice that during neap tides（26.5 cm/s）.（3） Significant differences of speeds are observed in the vertical profile.The maximum current speed occurs at either surface（spring and winter） or sub-surface（summer and autumn）,with the minimum current speed appearing at the bottom.The maximum average current speed of all layers is 57.9cm/s,which occurs in the 18-m layer during summer.（4） The average speed of the residual currents ranges from7.5 cm/s to 11.3 cm/s,with the strongest occurring in spring and weakest in winter.The residual currents of all layers are eastward during spring and winter,whereas northeastward or northward during summer and autumn.（5） The currents in the offshore of Changjiang Estuary are impacted collectively by diluted Changjiang River discharge,the Taiwan Warm Current,monsoon and tides.

Reconstruction Model of Ocean Observing Complex Virtual Instrument

With the newly proposed Global Ocean Observing Integration, ocean observing scope has been expanded from the region to the global, therefore the need of large-scale ocean observing system integration has become more and more urgent. Currently, ocean observing systems enabled ocean sensor networks are commonly developed by different organizations using specific technologies and platforms, which brings several challenges in ocean observing instrument （OOI） access and ocean observing system seamless integration. Furthermore, the development of ocean observing systems often suffers from low efficiency due to the complex prograrmning and debugging process. To solve these problems, a novel model, Complex Virtual Instrument （CVI） Model, is proposed. The model provides formal definitions on observing instrument description file, CVI description file, model calculation method, development model and interaction standard. In addition, this model establishes mathematical expressions of two model calculation operations, meanwhile builds the mapping relationship between observing instrument description file and CVI description file. The CVI based on the new model can achieve automatic access to different OOIs, seamless integration and communication for heterogeneous environments, and further implement standardized data access and management for the global unified ocean observing network. Throughout the development, integration and application of such CVI, the rationality and feasibility of the model have been evaluated. The results confirm that the proposed model can effectively implement heterogeneous system integration, improve development efficiency, make full usage of reusable components, reduce development cost, and enhance overall software system quality. We believe that our new model has great significance to promote the large-scale ocean observing system integration.

Intelligent Data Pre-processing Model in Integrated Ocean Observing Network System

There are a number of dirty data in observation data set derived from integrated ocean observing network system. Thus, the data must be carefully and reasonably processed before they are used for forecasting or analysis. This paper proposes a data pre-processing model based on intelligent algorithms. Firstly, we introduce the integrated network platform of ocean observation. Next, the preprocessing model of data is presemed, and an imelligent cleaning model of data is proposed. Based on fuzzy clustering, the Kohonen clustering network is improved to fulfill the parallel calculation of fuzzy c-means clustering. The proposed dynamic algorithm can automatically f＇md the new clustering center with the updated sample data. The rapid and dynamic performance of the model makes it suitable for real time calculation, and the efficiency and accuracy of the model is proved by test results through observation data analysis.

Research of Marine Sensor Web Based on SOA and EDA

A great deal of ocean sensor observation data exists, for a wide range of marine disciplines, derived from in situ and remote observing platforms, in real-time, near-real-time and delayed mode. Ocean monitoring is routinely completed using sensors and instruments. Standardization is the key requirement for exchanging information about ocean sensors and sensor data and for comparing and combining information from different sensor networks. One or more sensors are often physically integrated into a single ocean ‘instrument' device, which often brings in many challenges related to diverse sensor data formats, parameters units, different spatiotemporal resolution, application domains, data quality and sensors protocols. To face these challenges requires the standardization efforts aiming at facilitating the so-called Sensor Web, which making it easy to provide public access to sensor data and metadata information. In this paper, a Marine Sensor Web, based on SOA and EDA and integrating the MBARI's PUCK protocol, IEEE 1451 and OGC SWE 2.0, is illustrated with a five-layer architecture. The Web Service layer and Event Process layer are illustrated in detail with an actual example. The demo study has demonstrated that a standard-based system can be built to access sensors and marine instruments distributed globally using common Web browsers for monitoring the environment and oceanic conditions besides marine sensor data on the Web, this framework of Marine Sensor Web can also play an important role in many other domains' information integration.

Evaluating the Potential Economic Benefits of the New South Wales Node of Australia＇s Integrated Marine Observing System： [NSW-IMOS]

The Integrated Marine Observing System [IMOS] is an Australian national program for observing the oceans around Australia. As one of its important nodes, the New South Wales Integrated Marine Observing System （NSW-IMOS] aims to provide more accurate descriptions of the East Australian Current [EAC]. The purpose of this paper is to evaluate the potential economic benefits from NSW-IMOS. Six related sectors which can potentially be among its main beneficiaries are considered： beach recreation, commercial fishing, recreational fishing, recreational boating, natural hazard predictions, and oil spill mitigation. The 1% constant percentage increase evaluation method is used to estimate the potential economic benefits to these six beneficiaries. By using this method, our study shows that the total potential economic benefit for these sectors is estimated to be $ 6.07 million per year. We consider that this is indicative but not conclusive in demonstrating some of the potential economic benefits that can be provided from information gathered by NSW-IMOS facilities. We conclude with further evaluative approaches that could be used to provide more accurate estimates of potential economic benefits.

Advances in environmental DNA monitoring:standardization,automation,and emerging technologies in aquatic ecosystems

Environmental DNA(eDNA)monitoring,a rapidly advancing technique for assessing biodiversity and ecosystem health,offers a noninvasive approach for detecting and quantifying species from various environmental samples.In this review,a comprehensive overview of current eDNA collection and detection technologies is provided,emphasizing the necessity for standardization and automation in aquatic ecological monitoring.Furthermore,the intricacies of water bodies,from streams to the deep sea,and the associated challenges they pose for eDNA capture and analysis are explored.The paper delineates three primary eDNA survey methods,namely,bringing back water,bringing back filters,and bringing back data,each with specific advantages and constraints in terms of labor,transport,and data acquisition.Additionally,innovations in eDNA sampling equipment,including autonomous drones,subsurface samplers,and in-situ filtration devices,and their applications in monitoring diverse taxa are discussed.Moreover,recent advancements in species-specific detection and eDNA metabarcoding are addressed,highlighting the integration of novel techniques such as CRISPR-Cas and nanopore sequencing that enable precise and rapid detection of biodiversity.The implications of environmental RNA and epigenetic modifications are considered for future applications in providing nuanced ecological data.Lastly,the review stresses the critical role of standardization and automation in enhancing data consistency and comparability for robust long-term biomonitoring.We propose that the amalgamation of these technologies represents a paradigm shift in ecological monitoring,aligning with the urgent call for biodiversity conservation and sustainable management of aquatic ecosystems.