Background
Ocean optics is an experimental science for researching the optical properties of oceans, the propagation rule of light in oceans and detecting oceans by applying an optical technology, and the development of ocean optics cannot depart from the updating and the progress of a field measurement technology. After the sunlight is incident to the ocean, the sunlight interacts (absorbs or scatters) with seawater components (including seawater molecules and ocean particles) to generate an underwater spectral radiation field. The field measurement of the underwater profile radiation field is a main information source for detecting the ocean by optical remote sensing, is an important basis for establishing an optical ocean remote sensing model, and is also a basis for correcting and checking the authenticity of ocean water color remote sensing data products.
At present, a seawater section radiometric measurement system can be divided into shipborne buoy, anchor system buoy and BGC-Argo buoy measurement according to a carrying platform, BGC in BGC-Argo is an abbreviation of biogeochemical, Chinese meaning is biogeochemistry, Argo is an abbreviation of Array for Real-time Geostrophic ocean and Chinese meaning is a Real-time ocean parameter measurement Array, namely ocean section parameters can be rapidly and accurately measured by putting a plurality of buoys into ocean. Shipborne survey systems typically use marine radiometers with winches or free-fall optical platforms as carriers for profile radiometry. Therefore, the shipborne measurement system depends on a scientific investigation ship, can only carry out large-area station (point) observation, and cannot carry out long-term continuous (area) observation; but also time-consuming, labor-consuming and high-cost. Ocean optical radiation measurement systems based on anchoring buoys, such as ocean optical buoys MOBY managed and operated by the United states space agency and ocean optical buoys BOUSSOLE managed and operated by the European space agency, both perform ocean optical radiation measurement at a fixed depth (< 10 meters) on the surface layer of a fixed sea area, and cannot perform profile measurement or measurement in other sea areas. In recent years, ocean radiometers have been mounted on BGC-Argo buoys, which are used to float and submerge to measure ocean profile radiance. However, BGC-Argo buoys have limited electrical energy storage and, given long-term observations (> 2 years), the observation period is typically long (> 10 days), and are unable to capture changes in marine radiation or biogeochemical parameters in the short term; furthermore, BGG-Argo buoys are deep submerged (> 1000 meters) while marine optical radiation changes are typically only within the true light layer of seawater (< 200 meters). Therefore, the above mentioned marine optical radiation profile measurement systems, whether based on scientific research vessels, anchoring buoys and BGC-Argo buoys, all have their inherent disadvantages and cannot achieve long-term, high-frequency mobile measurement of marine profile radiation.
Disclosure of Invention
The invention aims to solve the technical problem of providing an autonomous floating and sinking type ocean optical environment light field profile measuring system.
The invention adopts the following technical scheme:
an autonomous floating and sinking type ocean optical environment light field profile measuring system is improved in that: the device comprises a floating ball floating on the sea surface, wherein a gravity attitude stabilizing device, a Beidou communication terminal and an inductive coupling data receiving unit electrically connected with the Beidou communication terminal are arranged on the floating ball, and an ocean spectral irradiance meter is arranged on the gravity attitude stabilizing device; one end of a plastic-coated steel cable is arranged at the bottom of a floating ball, the other end of the plastic-coated steel cable is hung with a tension hammer, a damper is arranged on the plastic-coated steel cable close to the floating ball, a lower damper is arranged close to the tension hammer, a lifting platform capable of sliding up and down along the plastic-coated steel cable is arranged between the upper damper and the lower damper, a cosine collector and a Gershun pipe are respectively arranged at the top and the bottom of the lifting platform, an underwater inductive coupling data transmission unit, a geomagnetic attitude sensor and a pressure sensor are arranged on the lifting platform, the underwater inductive coupling data transmission unit is connected and communicated with the inductive coupling data receiving unit through the plastic-coated steel cable, in addition, two sealed cabins are arranged on the lifting platform, each sealed cabin comprises a battery, a spectrometer and a control unit, the spectrometer of one sealed cabin is connected and communicated with the cosine collector, the spectrometer of the other sealed cabin is connected and communicated with the Gershun pipe, the control unit is connected and communicated with the spectrometer in the sealed cabin where the control unit is located and the underwater inductive coupling data transmission unit on the lifting platform, the geomagnetic attitude sensor and the pressure sensor, and the battery supplies power to the control unit and the spectrometer in the sealed cabin where the battery is located.
Furthermore, the gravity attitude stabilizing device and the Beidou communication terminal are installed at the top of the floating ball, and the inductive coupling data receiving unit is installed at the bottom of the floating ball.
Furthermore, an upper connecting rod is installed at the top of the lifting platform, and the cosine collector is fixedly installed at the end part of the upper connecting rod.
Furthermore, a lower connecting rod is installed at the bottom of the lifting platform, and the Gershun pipe is fixedly installed at the end part of the lower connecting rod.
Further, the length of the lower connecting rod is greater than the height of the lifting platform.
The invention has the beneficial effects that:
according to the profile measuring system disclosed by the invention, the lifting platform can slide up and down along the plastic-coated steel cable based on wave kinetic energy, no additional energy is consumed, and the lifting platform can be arranged in the ocean for long-term observation. The observation depth can be customized according to the research sea area, the profile speed is about 10 m/min, high-frequency profile observation can be realized, and 25 profiles can be measured when the depth of 100 m is measured in the daytime. And the integrated attitude sensor is used for performing shading correction on the observation data and providing high-quality observation data. And the inductive coupling data transmission unit is adopted to carry out cross-medium data transmission and transmit the measurement data in real time.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Embodiment 1, as shown in fig. 1, this embodiment discloses an autonomous floating and sinking type ocean optical environment light field profile measuring system, which includes a floating ball 4 floating on the sea surface, a gravity attitude stabilizing device 2, a beidou communication terminal 3 and an inductive coupling data receiving unit 5 electrically connected with the beidou communication terminal are installed on the floating ball, an ocean spectral irradiance meter 1 is installed on the gravity attitude stabilizing device and used for measuring the downward irradiance on the sea surface, and the gravity attitude stabilizing device is used for stabilizing the ocean spectral irradiance meter to keep the ocean spectral irradiance meter in an upright state; the one end of steel cable 7 is moulded to the package is installed in the floater bottom, the other end hangs tensioning hammer 17, close on the steel cable that the floater department installed attenuator 6 on the package is moulded, it installs down attenuator 16 to close on tensioning hammer department, it can follow package and mould gliding lift platform 8 about the steel cable between the upper and lower attenuator, lift platform is moulded steel cable unidirectional coupling with the package and is connected, the steel cable is moulded to the package and is the passageway of riding when lift platform up-and-down motion, so the package is moulded and is handled, can guarantee on the one hand and the interior unidirectional device coupling of lift platform more inseparabler, on the other hand is following induction coupling data transmission unit provides the data transmission passageway under water. A cosine collector 10 and a Gershun tube 12, also called as Gershun tube suite, are respectively arranged at the top and the bottom of a lifting platform and used for controlling an optical port fiber of ocean optics or the incident aperture of a spectrometer, belonging to the prior art of the optical measurement field and specifically showing a webpage https:// www.antpedia.com/news/69/n-2221569. html. An underwater inductive coupling data transmission unit 15, a geomagnetic attitude sensor and a pressure sensor are arranged on the lifting platform, the underwater inductive coupling data transmission unit is connected and communicated with the inductive coupling data receiving unit through a plastic-coated steel cable, in addition, a sealed cabin A13 sealed cabin B14 is also arranged on the lifting platform, each sealed cabin comprises a battery, a spectrometer and a control unit, the spectrometer of the sealed cabin B is connected and communicated with the cosine collector, the spectrometer of the sealed cabin A is connected and communicated with the Gershun tube, the control unit is connected and communicated with the spectrometer in the sealed cabin and the underwater inductive coupling data transmission unit on the lifting platform, the geomagnetic attitude sensor is connected and communicated with the pressure sensor, and the battery supplies power for the control unit and the spectrometer in the sealed cabin.
The Beidou communication terminal has the functions of satellite communication and real-time transmission of measurement data.
A power system is composed of a floating ball, a plastic-coated steel cable, an upper damping block, a lifting platform, a lower damping block and a tensioning hammer. The floating ball floats on the sea surface, moves up and down under the action of sea waves to provide power for the system, and the lifting platform automatically dives and ascends on the plastic-coated steel cable between the upper damping block and the lower damping block. By adjusting the balance weight, the lifting speed of the lifting platform can be controlled to be 0.2-0.5m/s, so that the high-frequency measurement of ocean section radiation is realized. In addition, the lifting platform descends by means of wave kinetic energy provided by the floating ball, and the lifting platform has long-term working advantages.
The data transmission system is composed of an inductive coupling data receiving unit (HEM) and an underwater inductive coupling data transmission unit (SSM), the SSM is communicated with the HEM on the water surface through a plastic-coated steel cable, and then data are wirelessly transmitted through a Beidou terminal.
The cosine collector and the Gershun pipe are both fixed on the lifting platform, and ocean profile radiation is measured at the uniform-speed rising stage of the lifting platform. The cosine collector is connected with a spectrometer in a sealed cabin through an optical fiber and is used for measuring the irradiance of a seawater section; the Gershun tube is connected with a spectrometer in another sealed cabin through an optical fiber and is used for measuring the seawater section radiance.
The geomagnetic attitude sensor provides the inclination angle and the azimuth angle of the lifting platform and is used for shading correction and data control of ocean irradiance and radiance data. The pressure sensor provides depth data of the lifting platform, and the depth data is used for work triggering and post data processing of the ocean radiometer.
In this embodiment, gravity gesture stabilising arrangement and big dipper communication terminal install at the floater top, and inductive coupling data receiving element installs at the floater bottom. An upper connecting rod 9 is arranged at the top of the lifting platform, and a cosine collector 10 is fixedly arranged at the end part of the upper connecting rod. The bottom of the lifting platform is provided with a lower connecting rod 11, and a Gershun pipe 12 is fixedly arranged at the end part of the lower connecting rod. The length of the lower connecting rod is greater than the height of the lifting platform. The overhanging distance of the upper connecting rod and the lower connecting rod is obtained by geometric optical calculation, and the shadow of the lifting platform is prevented from influencing the measuring result.
The autonomous floating and sinking type ocean optical environment light field profile measuring system disclosed by the embodiment can be distributed in the ocean for a long time, the lifting platform is submerged to the tensioning hammer under the action of wave power, then the lifting platform rises at a constant speed, and the downward spectral irradiance and the upward spectral radiance of the ocean are synchronously measured in the rising process. When the lifting platform rises to the position near the sea surface, the radiometer stops working, the SSM uploads data to the HEM through inductive coupling, and then the lifting platform starts submerging under the action of wave energy and repeats the next section measurement period. See the float platform of the invention patent application with application number 201811475281.0 for the implementation of the lift platform.
The profile measurement system has the advantages of long-term and high-frequency observation, can meet the requirement of ocean optical profile radiation business observation, and is used for optical oceanographic research, ocean water color remote sensing product correction and authenticity inspection research.
The embodiment further discloses a data processing method for processing the data measured by the profile measuring system, which includes the following steps:
step 1, depth offset correction, namely measuring pressure data and the vertical distance between the pressure data and a Gershun pipe and a cosine collector by using a pressure sensor, and calculating depth data of radiance and irradiance measurement;
step 2, controlling quality, recording inclination angle data of the lifting platform by using a geomagnetic attitude sensor, and removing data with an inclination angle larger than 5 degrees;
and 3, correcting the shadow, namely recording the azimuth angles of the Gershun pipe and the cosine collector according to the geomagnetic attitude sensor, calculating whether the azimuth angles are in the shadow of the floating ball, if so, calculating a shadow correction factor according to the following formulas (1) to (3), and correcting by using the following formula (4), wherein as shown in figure 2, the height of the lifting platform from the sea surface and the lengths of the upper connecting rod and the lower connecting rod are designed to avoid the influence of the floating ball and the lifting platform on the measurement of the radiance as much as possible. Based on Monte-Carlo simulations, the effect of floating body shadows on radiance measurements is expressed as
Wherein,
in order to be a shading correction factor,
nis the refractive index of the seawater and is,
is the angle of refraction of the sun in air,
in order to obtain the refraction angle of the sun in water,
ain order to be able to take advantage of the absorption coefficient,
r 0is the radius of the floating ball,
Z 0the distance between the upper connecting rod and the water surface,
for the up-line radiance measured at depth z,
the corrected up-line radiance of the shadow;
the cylindrical elevating platform has no effect on irradiance measurement, but affects up-going radiance measurement. The shade of the cylindrical lifting platform changes along with the elevation angle of the sun, and the lower connecting rodl 1The length should be long enough to avoid falling in the shadow of the cylindrical elevating platform. Ocean optical radiation measurement is generally at the zenith angle of the sun<The process is carried out at 70 degrees, and the lower connecting rod is the longest at the moment, so that the requirement of
Wherein,
in order to ensure the length of the lower connecting rod,
is the height of the cylindrical lifting platform,
is the angle of refraction of the sun in water. When the zenith angle of the sun is 70 degrees, the formula (4) can obtain
. Thus, the length of the lower connecting rod
Lifting platform needing to be larger than cylindrical
。
Step 4, calculating the diffusion attenuation coefficient, and respectively calculating the diffusion attenuation coefficient of the upward radiance by using a least square method according to the irradiance after the quality control, the radiance section measurement data and the corresponding depth data thereofK LuAnd down-going irradiance diffuse attenuation coefficientK Ed;
Step 5, based on the calculation of step 4K LuAndK Edcalculating the up-going radiance just under the water surfaceL u(0-) And down irradianceE d(0-) And underwater remote sensing reflectancer rs;
Step 6, calculating sea surface remote sensing reflectanceR rs,
Wherein,
the transmittance of radiance from the underwater surface to the surface above the water,
is the irradiance transmission from the upper surface to the lower surface,
is the water-air internal reflection coefficient.