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海水温度、盐度与深度的观测方法 PowerPoint Presentation
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海水温度、盐度与深度的观测方法

海水温度、盐度与深度的观测方法

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海水温度、盐度与深度的观测方法

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  1. 海洋学基础实验(水文部分) Physical Oceanographic Measurements & Data Processing 海水温度、盐度与深度的观测方法 15160081687 0592-2182348 zyliu@xmu.edu.cn 刘志宇 厦门大学海洋与环境学院 近海海洋环境科学国家重点实验室(厦门大学)

  2. 提 纲 温度观测 温盐深剖面观测 海表面温度的遥感观测 海上生活 盐度与电导率观测 压强与深度观测 2 4 5 6 3 1

  3. I. 压强与深度观测 Relationship between pressure and depth Measurements of Pressure (Depth)

  4. I. 压强与深度观测 Measurements of Pressure (Depth) OLD: strain gage (压力应变计, ±1%) ora pair of mercury reversing thermometers 4

  5. I. 压强与深度观测 MODERN:quartz(石英)transducerthat produces digital output Measurements of Pressure (Depth) Resolution: ±0.001% Accuracy: ±0.015 ℃ 5

  6. II. 温度观测 • 单点温度计 • 剖面温度计 • 液体温度计(水银) • 表面温度计 • 颠倒温度计 • 机械式温度计 • 温深自记仪(BT) • 电子温度计 • 热电式温度计 • 电阻式温度计 • 电子式温度计 • 晶体振荡式温度计 • 红外辐射计 Platinum Resistance Thermometer (铂电阻温度计) is the standard for temperature. It is used by national standards laboratories to interpolate between defined points on the practical temperature scale, and primarily to calibrate other temperature sensors.

  7. II. 温度观测 Surface Thermometer(OLD) Bucket thermometer (水桶温度计) The temperature of surface waters has been routinely measured at sea by putting a mercury thermometer into a bucket which is lowered into the water, letting it sit at a depth of about a meter for a few minutes until the thermometer comes to equilibrium, then bringing it aboard and reading the temperature before water in the bucket has time to change temperature. The accuracy is around 0.1℃. This is a very common source of direct surface temperature measurements.

  8. II. 温度观测 Reversing Thermometer(OLD) carried on Nansen bottles

  9. II. 温度观测 Reversing Water Bottle (Nansen bottle) Pairs of reversing thermometers carried on Nansen bottles were the primary source of sub-sea measurements of temperature as a function of pressure from around 1900 to 1970. The accuracy of mercury thermometers is up to ±0.001 ℃.

  10. II. 温度观测 Reversing Water Bottle (Nansen bottle) Bathythermograph (BT) was a mechanical device that measured temperature vs depth on a smoked glass slide. The device was widely used to map the thermal structure of the upper ocean, including the depth of the mixed layer before being replaced by the expendable bathythermograph in the 1970s. Expendable Bathythermograph (XBT) is an electronic device that measures temperature vs depth using a thermistor on a free-falling streamlined weight. The thermistor is connected to an ohm-meter on the ship by a thin copper wire that is spooled out from the sinking weight and from the moving ship. The XBT is now the most widely used instrument for measuring the thermal structure of the upper ocean. About 65,000 are used each year. (Accuracy: ±2% for depth, ±0.001℃ for temperature)

  11. II. 温度观测 Modern Thermometerthermistor (热敏电阻) based technology Since 1960s A SBE 3plus thermometer The sensing element is a glass-coated thermistor bead (珠形热敏电阻), pressure-protected inside an 0.8 mm diameter thin-walled stainless steel tube. Exponentially related to temperature, the thermistor resistance is the controlling element in an optimized Wien Bridge oscillator circuit. The resulting sensor frequency is inversely proportional to the square root of the thermistor resistance and ranges from approximately 2 to 6 kHz, corresponding to temperatures from -5 to +35℃. 11

  12. II. 温度观测 Modern Thermometer A SBE 3plus thermometer SPECIFICATIONS Range: -5.0 to +35 ℃ Resolution: 0.0003 ℃ at 24 samples per second Initial Accuracy: ±0.001 ℃ Stability: a drift less than 0.001 ℃ per 6 months period Response Time: 0.065 ± 0.010 seconds Depth Rating: 6800 m (Aluminum housing) or 10500 m (Titanium housing) 12

  13. III. 盐度与电导率观测 Definition & Facts • “Salinity” in the oldest sense is the mass of salt (expressed in grams) dissolved in a kilogram of seawater, unit is parts per thousand (‰). • UNESCO practical salinity scale of 1978 (PSS78) defines salinity in terms of an electrical conductivity ratio (relative to standard seawater), and so is dimensionless, unit is “psu” (practical salinity units). • The concept of salinity is useful because all of the constituents of sea salt are present in almost equal proportion everywhere in the ocean, i.e. an empirical Law of equal proportions. • Open-ocean salinities are generally 32-37 psu.

  14. III. 盐度与电导率观测 Measurements of Salinity • Oldest: evaporate the seawater and weigh the salts. • Old: titration method to determine the amount of chlorine(氯), bromide (溴) and iodine(碘). (prior to 1957) ±0.02‰ • Modern: Use seawater conductivity, which depends on temperature and salinity, along with accurate temperature measurement, to compute salinity. ±0.005 psu • Modern conductivity measurements: • (1) in the lab relative to a reference standard. • (2) profiling instrument (which MUST be calibrated to (1)).

  15. III. 盐度与电导率观测 Measurements of Salinity (Conductivity)

  16. III. 盐度与电导率观测 Measurements of Salinity (Conductivity) A SBE 4c conductivity sensor The sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes (铂电极).Conductivity cell (电导池)

  17. III. 盐度与电导率观测 Measurements of Salinity (Conductivity) A SBE 4c conductivity sensor SPECIFICATIONS Range: 0.0 - 7.0 Siemens/meter (S/m) Initial Accuracy: 0.0003 S/m Stability: a drift less than 0.0003 S/m per month Resolution: 0.00004 S/mat 24 Hz Response Time: 0.060 seconds Depth Rating: 6800 m (Aluminum housing) or 10500 m (Titanium housing) 17

  18. IV. 温盐深剖面观测 CTD (Conductivity, Temperature, Depth) Profiler 温盐深剖面仪

  19. IV. 温盐深剖面观测 CTD (Conductivity, Temperature, Depth) Profiler 温盐深剖面仪 19

  20. IV. 温盐深剖面观测 CTD (Conductivity, Temperature, Depth) Profiler 温盐深剖面仪 20

  21. IV. 温盐深剖面观测 CTD (Conductivity, Temperature, Depth) Profiler 温盐深剖面仪 21

  22. IV. 温盐深剖面观测 22

  23. IV. 温盐深剖面观测 特定层次水样的采集 23

  24. IV. 温盐深剖面观测 标准采水层次 24

  25. IV. 温盐深剖面观测 ARGO floats: measure ocean T and S while drifting with ocean currents, surface regularly to communicate with satellites to transmit data. 25

  26. IV. 温盐深剖面观测

  27. IV. 温盐深剖面观测 An Argo profile from the subtropical North Pacific (20.25ºN, 21.4ºW, May 15 2004).

  28. IV. 温盐深剖面观测 Moored Profiler (系缆式剖面仪)Based CTD Measurements 28

  29. IV. 温盐深剖面观测 Glider (水下滑翔机) Based CTD Measurements 29

  30. IV. 温盐深剖面观测 Towed (拖曳式) CTD Chain Measurements 30

  31. IV. 温盐深剖面观测 Towed Undulating Vehicle Based CTD Measurements 31

  32. V. 海表面温度的遥感观测 Based on Infrared Radiometers on Satellites Accuracy: ±0.6℃ (daily) 32

  33. V. 海上生活 Cruise Cruise Baby! http://www.cooa.unh.edu/cruise_cruise_baby.jsp