GB/T 39420-2020.Marine observation terminology.
1 Scope
GB/T 39420 defines the terms involved in marine hydrological observation and marine meteorological observation.
GB/T 39420 is applicable to marine observation and forecasting, marine disaster prevention and mitigation, marine environmental protection, marine scientific research and other related work and academic exchanges.
2 General terms
2.1
universal time coordinated; UTC
standard time at Greenwich.
2.2
Beijing time
standard time in the time zone where Beijing is located.
2.3
day boundary
the time boundary that defines the start and end of a day for marine hydrological and marine meteorological observations.
Note: The tide, wave, surface sea temperature, surface sea salinity and sea ice in the marine hydrological items within the jurisdiction of the People's Republic of China are based on 24:00 Beijing time (excluding 24:00), and the sea luminescence is based on sunrise; the marine meteorological items are based on 20:00 Beijing time (including 20:00). The marine hydrological and meteorological observations outside the jurisdiction of the People's Republic of China are based on the local time zone.
2.4
time calibration
Calibrate the observation system clock with the standard time.
2.5
travel time error
The difference between the observation system clock and the standard time after the observation is completed.
2.6
observation time
The time determined according to the observation requirements.
2.7
Supplementary measurement
When an item or element cannot be observed or the observation fails during the observation time, the measurement is carried out within the specified time after the observation time.
2.8
Missing measurement
Failure to carry out observation or supplementary measurement within the specified time.
2.9
Standard observation layer
The seawater observation layer divided according to different observation depth ranges.
Note: It can generally be divided into the surface layer, multiple intermediate layers and the bottom layer.
2.10
Sea surface layer
The water layer on the surface of the ocean.
This standard defines the terms involved in marine hydrological observation and marine meteorological observation. This standard is applicable to marine observation and forecasting, marine disaster prevention and mitigation, marine environmental protection, marine scientific research and other related work and academic exchanges.

ICS07.060
National Standard of the People's Republic of China
GB/T39420—2020
Marine observation terminology
Marine observation terminology2020-11-19Release
State Administration for Market Regulation
National Standardization Administration
2021-06-01Implementation
GB/T3942 0—2020
General terms
Observation elements
Marine hydrological elements
Marine meteorological elements
Observation classification·
Observation content:
Observation area and content
Observation type and means
5 Observation frequency·
References
This standard was drafted in accordance with the rules given in GB/T1.1-2009. This standard was proposed by the Ministry of Natural Resources of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Marine Standardization (SAC/TC283). GB/T39420—2020
This standard was drafted by: National Marine Standards and Metrology Center, National Marine Information Center, Hohai University, National Marine Technology Center, East China Sea Forecast Center of the State Oceanic Administration, and North Sea Bureau of the Ministry of Natural Resources. The main drafters of this standard are Yuan Lingling, Wu Shuangquan, Song Xiangzhou, Jiang Min, Gan Yi, Li Yangang, Zhang Bo, Wang Ying, Chen Fangfang, Si Yujie, Wang Weiyang and Fan Wenjing.
1 Scope
Ocean Observation Terms
This standard defines the terms involved in marine hydrological observation and marine meteorological observation. GB/T39420—2020
This standard is applicable to marine observation and forecasting, marine disaster prevention and mitigation, marine environmental protection, marine scientific research and other related work and academic exchanges. 2
General Terms
Universal time
Future time coordinated; UTC Greenwich location standard time.
Beijing time
Beijing time
Beijing time
Beijing time.
Day boundary
The time boundary of the beginning and end of a day for marine hydrological and marine meteorological observations. Note: The tide, wave, surface sea temperature, surface sea salinity and sea ice in the marine hydrological items within the jurisdiction of the People's Republic of China are based on 24:00 Beijing time (excluding 24:00), and the sunrise is the day boundary for sea luminescence; the marine meteorological items are based on 20:00 Beijing time (including 20:00). The marine hydrological and meteorological observations outside the sea areas under the jurisdiction of the People's Republic of China are based on the local time zone. Time calibration is to calibrate the observation system clock with the standard time. Travel time error is the difference between the observation system clock and the standard time after the observation is completed. Observation time is the observation time determined according to the observation requirements. Supplementary measurement is the activity of measuring within the specified time after the observation time when a certain item or element cannot be observed or the observation fails due to some reason.
missingmeasurement
Failure to make an observation or make up a measurement within the specified time. 2.9
Standard observation layer
standardobservationlayer
Seawater observation layer divided according to different observation water depth ranges Note: Generally, it can be divided into surface layer, multiple intermediate layers and bottom layer. 2.10
seasurfacelayer
Water layer on the surface of the ocean.
GB/T39420—2020
Note: The thickness of the surface layer is related to the observation elements, observation area and observation purpose. For example, the surface layer for temperature observation in seashore observation is 0m~0.5m, and the surface layer for current observation is 0m~3m.
Bottomseabottomlayer
Water layer close to the seabed.
Note: When the water depth is less than 50m, the bottom layer is the water layer 2m away from the bottom; when the water depth is within the range of 50m to 200m, the distance between the bottom layer and the bottom is 4% of the water depth; when the water depth is >200m, the distance between the bottom layer and the adjacent standard layer is not less than 25m. 3
Observation elements
Ocean hydrological elements
Sea water temperature
seawater temperature
A physical quantity that characterizes the degree of coldness and heat of seawater.
Surface water temperature
sea surface temperature
The temperature of the surface water of the ocean.
Bottom water temperature
sea bottom temperature
The temperature of the bottom water of the ocean.
Skin water temperature
seaskintemperature
Sea surface temperature.
salinity
A quantity that characterizes the amount of dissolved salts in seawater. Note: Salinity can be divided into absolute salinity and practical salinity. If not otherwise specified, salinity generally refers to practical salinity. [GB/T15920-2010, definition 2.1.9] 3.1.1.6
sea surface salinity
sea surface salinity
The salinity of the surface water of the ocean.
observationaldepth
Observational depth
The vertical distance from the sea surface to the observation point.
3.1.2 Ocean current
current
The macroscopic movement of seawater, characterized by velocity and direction. [GB/T15920—2010, definition 2.3.3]3.1.2.2
current speed
The distance traveled by seawater in unit time
Note: The unit is centimeters per second (cm/s), or meters per second (m/s). 2
『GB/T15920—2010, definition 2.3.33.1.2.3
current direction
The direction in which seawater flows.
Surface current speed
sea surface current speed
The speed of the seawater flowing at the surface of the ocean.
Surface current direction
sea surfacecurrentdirection
The direction of the seawater flowing at the surface of the ocean.
bottomcurrentspeed
bottom current speed
The speed of the seawater flowing at the bottom of the ocean.
bottomcurrentdirection
bottomcurrentdirection
direction of the flow of the bottom seawater of the ocean.
tidal current
periodic horizontal movement of seawater under the tidal force of celestial bodies such as the sun and the moon. 3.1.2.9
residual current
periodic current after filtering out tidal currents and other periodic flow components from the measured ocean currents. [GB/T15920—2010, definition 2.3.473.1.3 Waves
periodic fluctuations of the sea surface caused by wind.
Note: mainly includes wind waves and swells.
[GB/T15920—2010, definition 2.4.1]
windwave
periodic gravity waves generated by the direct action of wind on the dry water surface. [GB/T15920—2010, definition 2.4.24] 3.1.3.3
GB/T39420—2020
Waves left on the sea surface after the local wind speed decreases or subsides rapidly or the wind direction changes. [GB/T15920—2010, definition 2.4.25] 3.1.3.4
wavedirection
The direction of wave propagation.
[GB/T15920—2010, definition 2.4.13] 3.1.3.5
Wind wave direction
wind wave direction
Direction of wind wave propagation.
GB/T39420—2020
swelldirection
Swell direction
Direction of swell wave propagation.
wave height
The height difference between adjacent wave crests and troughs on the wave section. [GB/T15920—2010, definition 2.4.9] 3.1.3.8bzxz.net
Wave period
wave period
The time it takes for two consecutive wave crests (or wave troughs) on the wave section to pass through a fixed point. [GB/T15920—2010, definition 2.4.14] 3.1.3.9
Maximum wave height
maximumwaveheight
The maximum value of wave height in a continuous record of ocean waves. 3.1.3.10
maximum wave period
maximum wave period
wave period corresponding to the maximum wave height.
average wave height
average wave height
average value of all wave heights in the continuous wave record 3.1.3.12
average wave period
average wave height period
average value of the average wave height corresponding to the period. 3.1.3.13
significant wave height
significant wave height
1/3 height of the highest wave - third wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average value of the first 1/3 wave heights after sorting. [GB/T15920—2010, definition 2.4.36] 3.1.3.14
period of significant wave
Period of significant wave
The average value of each wave height corresponding to the period. 3.1.3.15
1/10 height of the highest-tenth wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average value of the first 1/10 wave height after sorting. [GB/T15920—2010, definition 2.4.37] 3.1.3.16
period of thehighest-tenth wave1/10 period of the highest-tenth wave
The average value of each wave height corresponding to the period of the highest-tenth wave. 3.1.3.17
wavenumber
The number of waves within a unit distance.
Note: Wave number represents the density of spatial fluctuations. 『GB/T15920—2010 definition 2.4.15
wavepattern
Appearance characteristics of ocean waves.
[GB/T12763.2—2007 definition 3.8]
wavescale
Grade of wave fluctuation intensity.
[GB/T15920—2010 definition 2.4.19］3.1.3.20
Wave crest line
Wave crest line
The connection of wave crests with the same specific phase, whose direction points perpendicularly to the direction of wave propagation. Note: Rewrite GB/T15920-2010 definition 2.4.23. 3.1.3.21
sea condition: sea state
Characteristics of the sea surface under the action of wind
Note: It is divided into 10 levels according to the presence or absence of waves and the shape of wave crests, the breaking of the crests and the amount of waves. [GB/T15920-2010 definition 2.4.18] 3.1.3.22
ocean wave spectrum
ocean wave spectrum
The structural pattern describing the distribution of the energy inside the waves relative to the frequency and direction of the constituent waves. Note: The wave spectrum can be divided into the frequency spectrum and the directional spectrum of the waves. 3.1.4 Tide
The periodic rise and fall of the sea surface caused by the tidal force of celestial bodies. [GB/T15920—2010 definition 2.5.1]
tidelevel
The height of the sea surface relative to the reference point when the tide occurs. [GB/T15920—2010 definition 2.5.2]
highwater
The highest tide level in a tidal cycle. [GB/T15920—2010 definition 2.5.3]
lowwater
The lowest tide level in a tidal cycle.
[GB/T15920—2010 definition 2.5.6]
High tide height
5highwater level
The height at which the tide level is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
low water level
lowwater level
The height of the tidal level in the period before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
high water hour
The moment when high water occurs.
[GB/T15920—2010. definition 2.5.5
GB/T39420—2020
GB/T39420—2020
low water hour
The middle moment of the tidal flat.
[GB/T15920—2010, definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010, definition 2.5.9]3.1.4.10
spring tide
One to three days after the first quarter (first day of the month) and the full moon (fifteenth day of the month), the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
The tide with a small tidal range caused by the subtraction of the tides caused by the moon and the sun around the first quarter (tenth and eighth day of the month) and the last quarter (twenty-second and twenty-third day of the month).
seiche
Free vibration of the sea surface in the form of main waves caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54] 3.1.4.13
Tidal datum level
tidal datum level
The starting surface for measuring the height of the sea tide.
Note: Generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
Fundamental leveling point
fundamentalbenchmark
The permanent height control point of the tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
Checkbenchmark
The leveling point used to check the zero point of the staffgauge and the elevation of the reading pointer. 3.1.4.17
Staff gauge check
Regularly check the height of internal and external gauges. 3.1.4.18
sealevel
The water surface with constantly changing sea level due to factors such as tidal force, wind, air pressure, runoff and hydrology. [GB/T15920—2010, definition 2.5.62] 3.1.5 Sea ice
seaice
Ice formed by the freezing of seawater.
『GB/T15920—2010. Definition 2.6.19
maximum wave height
maximum wave height
the maximum value of the wave height in the continuous wave record. 3.1.3.10
maximum wave period
maximum wave period
the wave period corresponding to the maximum wave height.
average wave height
average wave height
the average value of all wave heights in the continuous wave record 3.1.3.12
average wave period
average wave height period
the average value of the corresponding period of each wave height. 3.1.3.13
significant wave height
significant wave height
1/3 wave height of the highest-third wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average value of the first 1/3 wave heights after sorting. [GB/T15920—2010, definition 2.4.36] 3.1.3.14
period of significant wave
Period of significant wave
The average value of each wave height corresponding to the period. 3.1.3.15
1/10 height of the highest-tenth wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average value of the first 1/10 wave height after sorting. [GB/T15920—2010, definition 2.4.37] 3.1.3.16
period of thehighest-tenth wave1/10 period of the highest-tenth wave
The average value of each wave height corresponding to the period of the highest-tenth wave. 3.1.3.17
wavenumber
The number of waves within a unit distance.
Note: Wave number represents the density of spatial fluctuations. 『GB/T15920—2010 definition 2.4.15
wavepattern
Appearance characteristics of ocean waves.
[GB/T12763.2—2007 definition 3.8]
wavescale
Grade of wave fluctuation intensity.
[GB/T15920—2010 definition 2.4.19］3.1.3.20
Wave crest line
Wave crest line
The connection of wave crests with the same specific phase, whose direction points perpendicularly to the direction of wave propagation. Note: Rewrite GB/T15920-2010 definition 2.4.23. 3.1.3.21
sea condition: sea state
Characteristics of sea surface under wind force
Note: It is divided into 10 levels according to the presence or absence of waves and the shape of wave crests, the breaking of crests and the amount of waves. [GB/T15920-2010 definition 2.4.18] 3.1.3.22
ocean wave spectrum
ocean wave spectrum
The structural pattern describing the distribution of energy inside waves relative to the frequency and direction of the constituent waves. Note: The ocean wave spectrum can be divided into the frequency spectrum and the directional spectrum of ocean waves. 3.1.4 Tide
The periodic rise and fall of the sea surface caused by the tidal force of celestial bodies. [GB/T15920—2010 definition 2.5.1]
tidelevel
The height of the sea surface relative to the reference point when the tide occurs. [GB/T15920—2010 definition 2.5.2]
highwater
The highest tide level in a tidal cycle. [GB/T15920—2010 definition 2.5.3]
lowwater
The lowest tide level in a tidal cycle.
[GB/T15920—2010 definition 2.5.6]
High tide height
5highwater level
The height at which the tide level is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
low water level
lowwater level
The height of the tidal level in the period before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
high water hour
The moment when high water occurs.
[GB/T15920—2010. definition 2.5.5
GB/T39420—2020
GB/T39420—2020
low water hour
The middle moment of the tidal flat.
[GB/T15920—2010, definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010, definition 2.5.9]3.1.4.10
spring tide
One to three days after the first quarter (first day) and the full quarter (fifteenth day), the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
The tide with a small tidal range caused by the subtraction of the tides caused by the moon and the sun around the first quarter (tenth and eighth day) and the last quarter (twenty-second and twenty-third day).
seiche
Free vibration of the sea surface in the form of main waves caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54] 3.1.4.13
Tidal datum level
tidal datum level
The starting surface for measuring the height of the sea tide.
Note: Generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
Fundamental leveling point
fundamentalbenchmark
The permanent height control point of the tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
Checkbenchmark
The leveling point used to check the zero point of the staffgauge and the elevation of the reading pointer. 3.1.4.17
Staff gauge check
Regularly check the height of internal and external gauges. 3.1.4.18
sealevel
The water surface with constantly changing sea level due to factors such as tidal force, wind, air pressure, runoff and hydrology. [GB/T15920—2010, definition 2.5.62] 3.1.5 Sea ice
seaice
Ice formed by the freezing of seawater.
『GB/T15920—2010. Definition 2.6.19
maximum wave height
maximum wave height
the maximum value of the wave height in the continuous wave record. 3.1.3.10
maximum wave period
maximum wave period
the wave period corresponding to the maximum wave height.
average wave height
average wave height
the average value of all wave heights in the continuous wave record 3.1.3.12
average wave period
average wave height period
the average value of the corresponding period of each wave height. 3.1.3.13
significant wave height
significant wave height
1/3 wave height of the highest-third wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average value of the first 1/3 wave heights after sorting. [GB/T15920—2010, definition 2.4.36] 3.1.3.14
period of significant wave
Period of significant wave
The average value of each wave height corresponding to the period. 3.1.3.15
1/10 height of the highest-tenth wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average value of the first 1/10 wave height after sorting. [GB/T15920—2010, definition 2.4.37] 3.1.3.16
period of thehighest-tenth wave1/10 period of the highest-tenth wave
The average value of each wave height corresponding to the period of the highest-tenth wave. 3.1.3.17
wavenumber
The number of waves within a unit distance.
Note: Wave number represents the density of spatial fluctuations. 『GB/T15920—2010 definition 2.4.15
wavepattern
Appearance characteristics of ocean waves.
[GB/T12763.2—2007 definition 3.8]
wavescale
Grade of wave fluctuation intensity.
[GB/T15920—2010 definition 2.4.19］3.1.3.20
Wave crest line
Wave crest line
The connection of wave crests with the same specific phase, whose direction points perpendicularly to the direction of wave propagation. Note: Rewrite GB/T15920-2010 definition 2.4.23. 3.1.3.21
sea condition: sea state
Characteristics of sea surface under wind force
Note: It is divided into 10 levels according to the presence or absence of waves and the shape of wave crests, the breaking of crests and the amount of waves. [GB/T15920-2010 definition 2.4.18] 3.1.3.22
ocean wave spectrum
ocean wave spectrum
The structural pattern describing the distribution of energy inside waves relative to the frequency and direction of the constituent waves. Note: The ocean wave spectrum can be divided into the frequency spectrum and the directional spectrum of the ocean wave. 3.1.4 Tide
The periodic rise and fall of the sea surface caused by the tidal force of celestial bodies. [GB/T15920—2010 definition 2.5.1]
tidelevel
The height of the sea surface relative to the reference point when the tide occurs. [GB/T15920—2010 definition 2.5.2]
highwater
The highest tide level in a tidal cycle. [GB/T15920—2010 definition 2.5.3]
lowwater
The lowest tide level in a tidal cycle.
[GB/T15920—2010 definition 2.5.6]
High tide height
5highwater level
The height at which the tide level is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
low water level
lowwater level
The height of the tidal level in the period before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
high water hour
The moment when high water occurs.
[GB/T15920—2010. definition 2.5.5
GB/T39420—2020
GB/T39420—2020
low water hour
The middle moment of the tidal flat.
[GB/T15920—2010, definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010, definition 2.5.9]3.1.4.10
spring tide
One to three days after the first quarter (first day) and the full quarter (fifteenth day), the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
The tide with a small tidal range caused by the subtraction of the tides caused by the moon and the sun around the first quarter (tenth and eighth day) and the last quarter (twenty-second and twenty-third day).
seiche
Free vibration of the sea surface in the form of main waves caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54] 3.1.4.13
Tidal datum level
tidal datum level
The starting surface for measuring the height of the sea tide.
Note: Generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
Fundamental leveling point
fundamentalbenchmark
The permanent height control point of the tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
Checkbenchmark
The leveling point used to check the zero point of the staffgauge and the elevation of the reading pointer. 3.1.4.17
Staff gauge check
Regularly check the height of internal and external gauges. 3.1.4.18
sealevel
The water surface with constantly changing sea level due to factors such as tidal force, wind, air pressure, runoff and hydrology. [GB/T15920—2010, definition 2.5.62] 3.1.5 Sea ice
seaice
Ice formed by the freezing of seawater.
『GB/T15920—2010. Definition 2.6.115
1/10 height of the highest stone-tenth wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average of the first 1/10 wave height after sorting. [GB/T15920—2010, definition 2.4.37] 3.1.3.16
period of the highest stone-tenth wave1/10 period of the highest stone-tenth wave
The average value of each wave height corresponding to the wave period of the highest stone-tenth wave. 3.1.3.17
wavenumber
The number of waves within a unit distance.
Note: The wave number represents the density of spatial waves. 『GB/T15920—2010 definition 2.4.15
wavepattern
Appearance characteristics of ocean waves.
[GB/T12763.2—2007 definition 3.8]
wavescale
The level of wave fluctuation intensity.
[GB/T15920—2010 definition 2.4.19] 3.1.3.20
Wave crest line
Wave crest line
The connection of wave crests with the same specific phase, with its direction perpendicular to the direction of wave propagation. Note: Rewrite GB/T15920-2010 definition 2.4.23. 3.1.3.21
sea condition: sea state
Characteristics of sea surface under wind force
Note: It is divided into 10 levels according to the presence or absence of waves and the shape of wave crests, the breaking of crests and the amount of waves. [GB/T15920-2010 definition 2.4.18] 3.1.3.22
ocean wave spectrum
ocean wave spectrum
The structural pattern describing the distribution of energy inside waves relative to the frequency and direction of the constituent waves. Note: The ocean wave spectrum can be divided into the frequency spectrum and the directional spectrum of the ocean wave. 3.1.4 Tide
The periodic rise and fall of the sea surface caused by the tidal force of celestial bodies. [GB/T15920—2010 definition 2.5.1]
tidelevel
The height of the sea surface relative to the reference point when the tide occurs. [GB/T15920—2010 definition 2.5.2]
highwater
The highest tide level in a tidal cycle. [GB/T15920—2010 definition 2.5.3]
lowwater
The lowest tide level in a tidal cycle.
[GB/T15920—2010 definition 2.5.6]
High tide height
5highwater level
The height at which the tide level is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
low water level
lowwater level
The height of the tidal level in the period before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
high water hour
The moment when high water occurs.
[GB/T15920—2010. definition 2.5.5
GB/T39420—2020
GB/T39420—2020
low water hour
The middle moment of the tidal flat.
[GB/T15920—2010, definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010, definition 2.5.9]3.1.4.10
spring tide
One to three days after the first quarter (first day) and the full quarter (fifteenth day), the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
The tide with a small tidal range caused by the subtraction of the tides caused by the moon and the sun around the first quarter (tenth and eighth day) and the last quarter (twenty-second and twenty-third day).
seiche
Free vibration of the sea surface in the form of main waves caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54] 3.1.4.13
Tidal datum level
tidal datum level
The starting surface for measuring the height of the sea tide.
Note: Generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
Fundamental leveling point
fundamentalbenchmark
The permanent height control point of the tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
Checkbenchmark
The leveling point used to check the zero point of the staffgauge and the elevation of the reading pointer. 3.1.4.17
Staff gauge check
Regularly check the height of internal and external gauges. 3.1.4.18
sealevel
The water surface with constantly changing sea level due to factors such as tidal force, wind, air pressure, runoff and hydrology. [GB/T15920—2010, definition 2.5.62] 3.1.5 Sea ice
seaice
Ice formed by the freezing of seawater.
『GB/T15920—2010. Definition 2.6.115
1/10 height of the highest stone-tenth wave Arrange the wave height sequence measured continuously in a certain period from large to small, and take the average of the first 1/10 wave height after sorting. [GB/T15920—2010, definition 2.4.37] 3.1.3.16
period of the highest stone-tenth wave1/10 period of the highest stone-tenth wave
The average value of each wave height corresponding to the wave period of the highest stone-tenth wave. 3.1.3.17
wavenumber
The number of waves within a unit distance.
Note: The wave number represents the density of spatial waves. 『GB/T15920—2010 definition 2.4.15
wavepattern
Appearance characteristics of ocean waves.
[GB/T12763.2—2007 definition 3.8]
wavescale
The level of wave fluctuation intensity.
[GB/T15920—2010 definition 2.4.19] 3.1.3.20
Wave crest line
Wave crest line
The connection of wave crests with the same specific phase, with its direction perpendicular to the direction of wave propagation. Note: Rewrite GB/T15920-2010 definition 2.4.23. 3.1.3.21
sea condition: sea state
Characteristics of sea surface under wind force
Note: It is divided into 10 levels according to the presence or absence of waves and the shape of wave crests, the breaking of crests and the amount of waves. [GB/T15920-2010 definition 2.4.18] 3.1.3.22
ocean wave spectrum
ocean wave spectrum
The structural pattern describing the distribution of energy inside waves relative to the frequency and direction of the constituent waves. Note: The ocean wave spectrum can be divided into the frequency spectrum and the directional spectrum of the ocean wave. 3.1.4 Tide
The periodic rise and fall of the sea surface caused by the tidal force of celestial bodies. [GB/T15920—2010 definition 2.5.1]
tidelevel
The height of the sea surface relative to the reference point when the tide occurs. [GB/T15920—2010 definition 2.5.2]
highwater
The highest tide level in a tidal cycle. [GB/T15920—2010 definition 2.5.3]
lowwater
The lowest tide level in a tidal cycle.
[GB/T15920—2010 definition 2.5.6]
High tide height
5highwater level
The height at which the tide level is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
low water level
lowwater level
The height of the tidal level in the period before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
high water hour
The moment when high water occurs.
[GB/T15920—2010. definition 2.5.5
GB/T39420—2020
GB/T39420—2020
low water hour
The middle moment of the tidal flat.
[GB/T15920—2010, definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010, definition 2.5.9]3.1.4.10
spring tide
One to three days after the first quarter (first day) and the full quarter (fifteenth day), the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
The tide with a small tidal range caused by the subtraction of the tides caused by the moon and the sun around the first quarter (tenth and eighth day) and the last quarter (twenty-second and twenty-third day).
seiche
Free vibration of the sea surface in the form of main waves caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54] 3.1.4.13
Tidal datum level
tidal datum level
The starting surface for measuring the height of the sea tide.
Note: Generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
Fundamental leveling point
fundamentalbenchmark
The permanent height control point of the tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
Checkbenchmark
The leveling point used to check the zero point of the staffgauge and the elevation of the reading pointer. 3.1.4.17
Staff gauge check
Regularly check the height of internal and external gauges. 3.1.4.18
sealevel
The water surface with constantly changing sea level due to factors such as tidal force, wind, air pressure, runoff and hydrology. [GB/T15920—2010, definition 2.5.62] 3.1.5 Sea ice
seaice
Ice formed by the freezing of seawater.
『GB/T15920—2010. Definition 2.6.16]
High water level
5highwater level
The height at which the tide is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
Low water level
lowwater level
The height at which the tide is in a state of no tide during a period of time before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
High water hour
The moment when high tide occurs.
[GB/T15920—2010.Definition 2.5.5
GB/T39420—2020
GB/T39420—2020
Low water hour
lowwater hour
The middle moment of the cessation of tide.
[GB/T15920—2010,Definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010,Definition 2.5.9]3.1.4.10
spring tide
One to three days after the first day of the lunar month and the fifteenth day of the lunar month, the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
A tide with a small tidal range formed by the subtraction of the tides caused by the moon and the sun around the first quarter (the 10th and 8th day of the first lunar month) and the last quarter (the 22nd and 23rd day of the first lunar month).
seiche
Free vibration of the sea surface in the form of main waves caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54]3.1.4.13
tidal datum level
tidal datum level
The starting surface for measuring the height of the sea surface tide.
Note: It is generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
fundamental benchmark
fundamentalbenchmark
The permanent height control point of a tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
checkbenchmark
abenchmark used to check thezeropointofthestaffgaugeandtheheightofthereadingpointer. 3.1.4.17
staffgaugecheck
staffgaugecheck
regularlychecktheheightoftheinternalandexternalgauges. 3.1.4.18
sealevel
a surface of water with a constantlychangingseawaterheightaffectedbytidalforce,wind,airpressure,runoffandhydrology. [GB/T15920—2010,definition2.5.62]3.1.5seaice
seaice
iceformedbythefreezingofseawater.
『GB/T15920—2010. Definition 2.6.16]
High water level
5highwater level
The height at which the tide is in a state of equilibrium during a period of time before and after high tide. [GB/T15920—2010, definition 2.5.4]
Low water level
lowwater level
The height at which the tide is in a state of no tide during a period of time before and after low tide. [GB/T15920—2010, definition 2.5.7]3.1.4.7
High water hour
The moment when high tide occurs.
[GB/T15920—2010.Definition 2.5.5
GB/T39420—2020
GB/T39420—2020
Low water hour
lowwater hour
The middle moment of the cessation of tide.
[GB/T15920—2010,Definition 2.5.8]
tidal range
The difference between adjacent high and low tide levels.
[GB/T15920—2010,Definition 2.5.9]3.1.4.10
spring tide
One to three days after the first day of the lunar month and the fifteenth day of the lunar month, the tide with a large tidal range caused by the addition of the tides caused by the moon and the sun. 3.1.4.11
neaptide
A tide with a small tidal range formed by the subtraction of the tides caused by the moon and the sun around the first quarter (the 10th and 8th day of the first lunar month) and the last quarter (the 22nd and 23rd day of the first lunar month).
seiche
Free vibration of the sea surface in the form of a main wave caused by the inertia of external forces in closed or semi-enclosed waters. [GB/T15920—2010, definition 2.5.54]3.1.4.13
tidal datum level
tidal datum level
The starting surface for measuring the height of the sea surface tide.
Note: It is generally taken as the theoretical lowest tide level in the local area. 3.1.4.14
fundamental benchmark
fundamentalbenchmark
The permanent height control point of a tide gauge station.
zeropointofstaffgauge
zeropointofstaffgauge
zeropointofthelocaltidegaugestation.
checkbenchmark
abenchmark used to check thezeropointofthestaffgaugeandtheheightofthereadingpointer. 3.1.4.17
staffgaugecheck
staffgaugecheck
regularlychecktheheightoftheinternalandexternalgauges. 3.1.4.18
sealevel
a surface of water with a constantlychangingsealevelaffectedbytidalforce,wind,airpressure,runoffandhydrology. [GB/T15920—2010,definition2.5.62]3.1.5seaice
seaice
iceformedbythefreezingofseawater.
『GB/T15920—2010. Definition 2.6.1
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