Introduction to Marine Data Source Analysis and Sharing

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Introduction
The development of marine science has roughly gone through three stages: the first is the theoretical traction stage due to the lack of observational data, the scientific research at this stage mainly relies on the establishment of scientific theories to explain ocean phenomena.The second is the observational traction stage, with vigorous development of different observation means and instruments and equipment, human footprints have advanced from the offshore to the deep sea, and established a three-dimensional observation network covering the world's oceans.The third is the data traction stage.With the continuous enrichment of observational technologies, data sources are becoming more extensive and diverse, and the amount of data has increased to the PB level [1].It provides a strong foundation for scientific research, social economy and national security in the field.
The ocean data described in this paper [2]mainly refers to the data obtained from various types of observations and simulations conducted in the marine natural environment, including the dynamic elements of the background field of the ocean environment and the ecological elements of the ocean environment.

Ocean Data Sources
There are a wide range of marine data sources.According to the means and methods of production, this paper summarizes the marine data sources into on-site observation data, satellite telemetry data and reanalysis assimilation data.The relationship between the three is inseparable and complementary to each other.On-site observation mainly refers to shore-based, sea/subseabased and air-based: shore-based refers to the coastal, island, offshore platform and other fixed ocean observation platform, the coastal waters of the marine hydro-meteorological environment, marine ecological environment for observation and monitoring, to obtain a long time series of marine information; sea/subsea base refers to the most basic mobile observation platform, such as marine research vessels, to obtain marine hydrometeorology, marine biochemistry, seafloor topography and geomorphology, seafloor sediments, marine geophysical fields and other elements, which are in the dominant position in marine data sources; spacebased in this species refers to unpowered aerostats flying in the stratosphere, including zero-pressure high-altitude balloons, large overpressure balloons, small overpressure balloons, infrared hot air balloons, etc., generally used to measure the physical and chemical properties of the atmosphere above the near-surface layer, and highaltitude balloons are mainly used in oceanographic surveys to observe meteorological elements.Satellite telemetry data refers to all kinds of marine and atmospheric remote sensing products reflected by altimeters, radiometers, and scatterometers carried by marine satellites and meteorological satellites, which have the advantages of wide coverage, fast speed, high efficiency, and not limited by national boundaries and geography compared with shore-based, sea/subsea-based and air-based observation means.In addition, the reanalysis data based on the dynamic ocean-atmosphere model and assimilation technology effectively make up for the uneven spatial and temporal distribution of the data, and are irreplaceable fundamental information for gaining insight into the ocean-atmosphere motion at multiple spatial and temporal scales and exploring the mechanisms of sea-air interaction.
amount of marine survey data, and successively carried out major national projects, polar expeditions and ocean resource and environment surveys.The results obtained have gained important progress in related fields and expanded the national influence.China's marine scientific investigation has undergone a gradual metamorphosis from none to have, the region from offshore to ocean, the ship from backward to advanced, equipment from reliance on imports to independent development, investigation and research personnel from less to more, the investigation environment from difficult to superior.

Domestic marine observation/monitoring
business.
China's modern independent operational marine observation began in the early 20th century.In 1958, 119 marine hydrometeorological observation stations were set up along the coast of the country.From 1991 to 1995, the key project voyages of the "East China Sea Shelf Edge Ocean Flux Research" were carried out .From then to 1999, more than 80 voyages were carried out in the Taiwan Strait, East China Sea, West Philippine Sea and other waters, all of which were included in the international JGOFS.The plan has effectively promoted the study of ocean fluxes at the edge of the international shelf.

GEOTRACES International Data Assembly Centre(GDAC) 2010~ present
China's first GEOTRACES crosssectional survey voyage was led by Xiamen University from April to June 2019, and the mission was successfully completed by the Xiamen University "Jiageng" scientific research ship [4] , demonstrating the comprehensive strength of China's marine scientific research.

Synthetic Aperture Radar (SAR) [9]data,
which is an active microwave remote sensing imaging radar, is usually used to observe the direction spectrum of sea surface wind, internal waves, and ocean waves [10], and can also monitor sea ice movement and marine oil spills.Since the frequency band of synthetic aperture radar is the microwave band, the instrument can work normally even in the dark, with the advantages of all-day, all-weather and penetrate all features imaging [11], its use is very wide.
Spaceborne radar has developed rapidly in the 1990s.So far, SAR has been carried on some launched satellites, such as Seasat SAR, Almaz SAR, JERS-1 SAR, and ERS-1/2 SAR.In 1999, ESA launched the Envisat-1 satellite loaded with ASAR.In 2001, Canada launched Radar Satellite 2 with full polarization measurement capability, and LightSAR launched in 2002 is a practical imaging radar with L-band multi-polarization and interferometry and scanning modes.In 2006, Japan launched the ALOS satellite, and the PALSAR radar sensor carried is a multipolarization, multi-mode radar system.Provide rich data sources for the development of digital earth .

Reanalysis data
The lack of high-quality, high-resolution, long-term and continuous global observations due to the heterogeneous spatial and temporal distribution of global oceanatmosphere observations has posed great difficulties and challenges to the in-depth understanding of global oceanatmosphere changes, cognition of climate evolution patterns and unveiling of phenomenal mechanisms.Based on the ocean-atmosphere dynamic model, scholars use data assimilation technology to assimilate historical observation data into the ocean-atmosphere dynamic model, and obtain a class of product datasets [12] that effectively solve the above problems.This chapter mainly introduces the dynamic data used for the driving field of the ocean-atmosphere model , which is based on the reanalysis data of the observational data.wind, zonal wind and cloud cover, etc., the space covers the world.
3 ECMWF ECMWF [13]   Provide weather observation data and model forecast products as well as related data for global sea-air model calculation [14] .The data set provided by ECMWF contains a variety of variables, with a grid resolution of 2.5°×2.5°,144 points in the latitude and 73 points in the meridian, and the data time resolution is four times a day.

SODA [14] University of Maryland
The assimilation time of SODA 2.2.4 is more than 100 years, the spatial range is 0.25°E~359.75°E,75.25°S~89.25°N,the horizontal resolution is 0.5°×0.5°,and the vertical direction is divided into 40 unequally spaced layers, From 10m to 250m, the time resolution is monthly average, and the elements include temperature, salinity, zonal flow velocity, meridional flow, sea surface height, zonal wind and meridional wind.

GECCO [16] UH
Developed on the basis of ECCO products released by MITgcm [14 -15] unequally spaced layers, ranging from about 10m to 500m, Product containing 6 variables: temperature, salinity, zonal flow velocity, meridional flow velocity, vertical flow and sea surface height.

HYCOM [14] U.S. Naval Research Laboratory
Product [17] elements include water temperature, salinity, zonal mobility, meridional mobility, and sea surface height.The time span of the reanalysis data product is 1992~2012, the time resolution is 1 day, the latitude range is 80.48°S~80.48°N,the horizontal resolution is 1/12°, and the vertical direction is 40 layers with unequal distances.

OFES
The Earth Simulator Center, Japan The average horizontal resolution of the product is about 12km, and the output variables are re-interpolated to a standard grid of 1°×1°.The vertical resolution is 50 layers, and the time resolution is the daily average.

GLORYS [18] CMEMS
The time span of the product is from 1993 to 2015, and the time resolution is the daily average, including 10 variables, namely water temperature, salinity, and zonal flow velocity.

FIOCOM First Institute of Oceanography
The horizontal resolution is 0.1°×0.1°, the vertical is divided into 54 layers, the depth range is 1m~5316m, and the time resolution is 1d, including 5 variables: temperature, salinity, meridional current velocity, zonal current velocity and sea surface height.

CRA China Meteorological Administration
The product has a horizontal resolution of 34km and a time resolution of 6hr.It is divided into 64 layers vertically, and the height range is from the ground to 55km.

Ocean big data sharing
The progress of marine science depends on the effective use and full sharing of scientific data.Faced with the huge amount of big data generated every day, countries have invested a lot of manpower and material resources to actively promote the sharing of marine scientific data.This chapter mainly summarizes the information released by the data sharing platform to provide reference for scientific researchers in need.

Domestic marine data sharing
Domestically, China has actively advocated information sharing in marine data sharing work, fully exploited marine information resources, made very important contributions in relevant international cooperation and programs, effectively promoted the development of marine scientific research, and increasingly reflected the status of a great power.The national marine authorities and relevant sea-related ministries have released a large amount of marine data information for the use of the society through various ways and with the help of national scientific data centers and characteristic sharing platforms.

Foreign Ocean Data Sharing
In foreign countries, various international organizations are committed to the sharing of global marine data, formulating corresponding data policies and management methods, and upgrading marine data sharing to development strategies and national policies to provide data support for various marine fields.

Table 1 .
such as Argo, WOD, DBCP, ICOADS and other international organizations/plans.It has realized real-time update and release of observation data and information products such as ocean temperature and salinity, ocean currents, meteorology, geology and topography for global users.Major marine international programmes China's Argo Ocean Observation Project has built the basic platform of China's Argo Ocean Observation Network for the first time in the northwestern Pacific Ocean adjacent to my country, creating a long-term, high-resolution and largescale real-time monitoring of temperature and salinity in the water depth of 0-2000 meters in my country.
quality of satellite remote sensing data has been greatly improved.This chapter mainly introduces several types of commonly used satellite data.surface coverage, clouds, aerosols, water vapor, and fire.MODIS provides image data products with high radiometric resolution of all surfaces in the world, sunlight reflection and day and night thermal radiation, and the image resolution is between 0.25 and 1 km.Basic objectives of MODIS measurements include: land and ocean surface temperature and ground fire, ocean [5] Satellite remote sensing dataThe United States successfully launched the first meteorological satellite in 1960[5], and launched the first ocean satellite again in 1978.Subsequently, active remote sensing technology corresponding fast algorithms and inversion methods have formed a situation of rapid development, and remote sensing ocean and atmospheric science application models are becoming increasingly mature.Based on the development of the aerospace industry, the day, covering the global ocean and the time range from 1981 to the present.The Moderate Resolution Imaging Spectroradiometer (MODIS) is an important remote sensing instrument developed by NASA.It is a passive imaging spectroradiometer that can acquire images of targets such as land and ocean temperature, primary productivity, land

Table 2 .
Major reanalysis data products in the marine sector

Table 3 .
Domestic Marine Data Sharing

Table 4 .
Oceanographic data sharing by foreign countries and international organizations