JPS6035618B2 - How to measure vertical temperature distribution in water - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring vertical temperature distribution in water.

There are many ways to measure vertical temperature distribution underwater.

These methods include, as typified by BT and XBT,
There is a problem in that depth information and temperature information must be measured by completely different means. In these methods, bellows or the like was used to obtain depth information, or the falling velocity of a falling object was integrated over time. Therefore, the device using the former method is expensive and has the drawback of being large in size due to mechanical operation, and the device using the latter method has the drawback of poor accuracy. Temperature information has been obtained by using the resistance change due to temperature of a thermistor or by using the thermal coefficient of the metal wire. Therefore, the disadvantage of the device using the former method is that
Thermistors require a response time to change resistance due to temperature changes, and are weak against physical forces. Because precision is required, it is expensive and difficult to handle. The method according to the present invention solves the problems of the conventional methods as described above, and uses a signal obtained by modulating a carrier wave with pulses as a signal wave, and calculates changes in the frequency and pulse interval of the received signal wave. This provides a method that allows you to easily and accurately obtain the vertical temperature distribution in water just by reading it.

The method of the present invention will be described below based on one embodiment thereof.

FIG. 1 is a block diagram of a measurement system based on this embodiment, and 1 is a transmission system. In this system 1, 2 is an oscillation circuit, for example, a crystal oscillator with a stable oscillation frequency, 3 is a pulse modulation circuit, 4 is an amplification circuit, and 5 is an electro-acoustic converter. 6 is a receiving system.

In this system 6, 7 is an acoustic-electric conversion section, 8 is a circuit for reading the received pulse interval, 9 is a circuit for reading the frequency of the carrier wave of the pulse signal, and 10 is a circuit for processing information from the circuit sections 8 and 9. , 11 is a bar coder. In the transmission system 1, a carrier signal having a frequency f generated by an oscillation circuit 2 is modulated in a pulse modulation circuit 3 into a pulse signal that is intermittently interrupted at intervals t. In the transmission system 1, the frequency f and the interval t are kept constant. This modulated signal is converted into an acoustic signal in the electro-acoustic converter and radiated into the water. The sound waves propagate through water, are received by the receiving system 6, and are converted into electrical signals by the acoustic-electric converter 7. Then, a circuit 8 detects the signal pulse interval, and a circuit 9 reads the carrier wave frequency. The information obtained is processed by the circuit 10 to obtain the depth of the transmission system 1 and the temperature at that position. Information regarding depth and temperature is recorded on the bar coder 11. A method for obtaining depth information and temperature information will be described using FIGS. 2 and 3.

The dropped transmission system 1 descends into the water as shown in FIG. 3 while generating pulse signals of carrier frequency f and interval t as shown in FIG. 2A. The interval and carrier frequency of the signals reaching the receiving system 6 change depending on the depth and temperature, resulting in a waveform as shown in FIG. 2B. In Fig. 3, point i is the position where the pulse signal is transmitted, △xi is the distance between point i and point i11, V'i is the speed of sound at point i, and Vi is the average speed of sound at point i and point i+1. It is.

V' is calculated by actually measuring the temperature of the water surface.

For example, the following Wayne D. Wmson's empirical formula is used. V=1449.22 ten△VT+△VP ten△Vs ten△V
sTP△VT=4.6233T-5.4585xlo-
? r212・822×10−4Tmar−5・07×10−
7T4△VP: 1.60518×10-IP+1.02
79xlo-5P2 3.451×10-9P3-3.
503×10-144ΔVs=1.391(S-35)
-7.8×10-2(S-35)2 △VMp=(S-35)(-1.197×10-2T+
2.61×10-4P-1.96×10-72-2.0
9XIO-ya T) 10P (12.796xlo-4T+1
．． 3302xlo-5T2-6.644xlo-8)
Juhei (12.391×10-7T+9.286xl0-
lOT2) --, 745xlo-1 where V: Sound velocity (m/s), T: Water temperature (00) P: Hydrostatic pressure (k9/S)
, S: Salinity (%) In reality, the speed of sound V has a relatively small effect on salinity, so if you know the water temperature T and the hydrostatic pressure P, you can find the speed of sound V.

By subtracting the preset carrier frequency 〆 from the carrier frequency of the pulse signal sent from point 1, the change Δf, becomes known, and the velocity v, of point 1 can be found from the equation below. VI=-△frVI”
E 1f + △f, Here, in the transmission system 1, if t is set short during the pulse of the transmission signal, the change in water temperature during the time t falling from the water surface to point 1 is very small, and {in formula 1' The effect of water temperature changes can be ignored.

Next, if the transmitting system 1 receives the pulse signal generated at point 2 and knows the pulse interval t+△t of the received signal, then △above V
3≦Dimension...[21] Therefore, the average sound velocity at points 1 and 2, V, can be found from the following equation.

V. = device~...'3' Since the transmission pulse interval t is short, the transmission system 1
The falling distance is small, and the following approximation can be made.

V′2=VI”-(
4. In the same manner, −△frV′i
…[51Vi=Complete≠”Vi=Vessel+W
The depth information is obtained from the falling velocity meter at each point 1, 2, 3, ..., 1, ... of the dropped transmission system, using formula '5}.
is found, therefore n D=i≧lt・v, (D: depth) ... [7',
You can ask for it.

Further, the temperature information can be obtained from the sound velocity Vi at point i obtained by the formula '6}, from the above-mentioned Wa strike e○. The hydrostatic pressure can be calculated from the depth using Wmson's empirical formula, ignoring the salinity term. As described above, in the method of the present invention, a transmission system that generates pulse signals with a constant carrier frequency and constant intervals is lowered into the water, receives the pulse signals propagating through the water, and receives the carrier wave frequency of the received signal. Depth information and temperature information are obtained from the change in pulse interval and the change in pulse interval.

According to this method, a signal with a constant carrier frequency and interval is sent, and information regarding depth and temperature can be obtained from changes occurring in the water. Further, there is no need to provide a special sensor for both depth and temperature, making it possible to obtain an extremely small, simple, robust, and inexpensive device. Furthermore, since it uses the Doppler effect, a principle that does not require response time, there is no measurement error due to response time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a transmitting system and a receiving system for explaining the method of measuring vertical temperature distribution in water according to the present invention, FIG. FIG. 3 is a diagram showing the waveforms of received signals, respectively, and is a diagram for explaining that depth information and temperature information are obtained using the configuration shown in FIG. 1. 1... Transmission system, 2... Oscillation circuit, 3.
...Pulse modulation circuit, 4... Increase circuit,
5... Electrical-acoustic converter, 6... Receiving system, 7... Acoustic-electrical converter, 8...
A circuit for reading the pulse interval, 9... A circuit for detecting the frequency of a carrier wave, 10... A circuit for processing the output of the circuits 8 and 9, 11... A recorder. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A transmitting system that generates pulse signals with a constant carrier frequency and constant intervals is lowered into the water, receives the pulse signals propagating through the water, and detects the change in the carrier frequency and the change in the pulse interval of the received signal. A method for measuring vertical temperature distribution in water, characterized by obtaining depth information and temperature information from