CN109507761B - Method for obtaining accurate rainfall data based on equivalent rainfall intensity - Google Patents
Method for obtaining accurate rainfall data based on equivalent rainfall intensity Download PDFInfo
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Abstract
The invention provides a method for obtaining accurate rainfall data based on equivalent rainfall intensity, which is characterized by comprising the following steps of: step S1: under the condition of a test environment, different constant rainfall intensity values are set, the tipping bucket type rainfall sensor is tested, and an equivalent rainfall intensity function is constructed according to the test result. Step S2: and obtaining an instant rainfall function according to the equivalent rainfall function. The invention subverts the existing method for obtaining rainfall data by the tipping bucket type rainfall sensor, breaks the conventional effect that the error is smaller under the condition of higher precision, introduces the acquisition of the time interval of two times of tipping of the tipping bucket under the condition of not changing the main body component of the conventional tipping bucket type rainfall sensor, and constructs a brand-new solution scheme for obtaining the accurate rainfall by combining the characteristic attribute of the tipping bucket type rainfall sensor.
Description
Technical Field
The invention relates to the field of meteorological data acquisition, in particular to a method for obtaining accurate rainfall data based on equivalent rainfall intensity.
Background
Precipitation data is used as an important meteorological data index, and has wide application and necessary significance. At present, precipitation data generally mainly take the total rainfall of statistics in a period, mainly realize the collection of real-time precipitation data and upload to meteorological monitoring terminal and summarize and count through devices such as rainfall sensor (rain gauge). The current mainstream rainfall sensor is a tipping bucket rainfall sensor.
The tipping bucket type rainfall sensor is a hydrological and meteorological instrument, and is used for measuring the rainfall in nature, and simultaneously converting the rainfall into digital information quantity expressed in a switching value form for output so as to meet the requirements of information transmission, processing, recording, display and the like. The traditional tipping bucket rainfall sensor can only achieve errors of +/-4% generally, and requirements on historical records and data analysis of weather are increasingly not met.
For the existing tipping bucket type rainfall sensor, the final total rainfall is basically obtained through preset precision (the quantity of water which can cause tipping bucket overturning is positively correlated) and the switching times (switching quantity) of a reed switch triggered by the tipping bucket overturning. If the calculation method has errors, the error is adjusted by an error correction method, so that the finally output switching value can be close to the ideal switching value as much as possible, and the errors are reduced.
However, with the current requirement for higher and higher precision of rainfall data, almost all of the adopted error correction schemes are not necessarily able to properly eliminate the influence of errors, and even new errors may be introduced, for example, although the rainfall sensor of the double-tipping bucket can eliminate dynamic loss (because rainfall is a continuous process, when the tipping bucket on one side receives rainwater and reaches a tipping bucket moment threshold, and when the tipping bucket on the other side receives rainwater, a part of rainwater is not received by the tipping bucket and is not included in the metering range of the tipping bucket type rainfall sensor, which may cause error loss), new random errors are introduced, or because of the limit of processing precision, the elimination of errors cannot be realized within the range of cost and technical capability, and the operation process of correcting errors is tedious and time-consuming and labor-consuming.
Disclosure of Invention
In order to solve the problems of defects and deficiencies in the prior art, the invention adopts a brand-new problem analysis and scheme design idea, and specifically adopts the following technical scheme without changing the main body component of the tipping bucket type rainfall sensor:
a method for obtaining accurate rainfall data based on equivalent rainfall intensity is characterized in that: the rain sensor based on the tipping bucket comprises the following steps:
step S1: under the condition of test environment, different constant rain intensity values are set
Testing the tipping bucket type rainfall sensor, and constructing an equivalent rain intensity function according to a test result:
G(u,t)＝0；
wherein the unit of the equivalent rain intensity u of the bucket time length t is mm/min; the bucket duration t is the time interval of two overturning of the tipping bucket, and the unit is s;
step S2: according to the followingEffective rain intensity function and
obtaining an instant rainfall function:
J(h,t)＝0；
the instant rainfall h is the rainfall generated by the equivalent rainfall intensity of the bucket duration t within the bucket duration t.
Preferably, in step S1, the concrete method for testing the dump-bucket rainfall sensor and constructing the equivalent rain intensity function according to the test result is as follows:
under the condition of the test environment, a plurality of different conditions are set and are at (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
Then, measuring a corresponding t value; and establishing a mapping corresponding relation between u and t;
wherein u ismaxIs an extreme value of rain intensity.
Preferably, in step S1, the concrete method for testing the dump-bucket rainfall sensor and constructing the equivalent rain intensity function according to the test result is as follows:
under the condition of the test environment, a plurality of different conditions are set and are at (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
And measuring a corresponding t value, and obtaining an undetermined equivalent rain intensity function in a fitting mode according to a test result:
the undetermined equivalent rain intensity function comprises n (n is more than or equal to 2) fitting parameters, and the values of the fitting parameters are obtained by the following method:
under the condition of the test environment, n different ones are set to be (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
Then, the corresponding t value is measured to obtain n groups of different values (u)1,t1)、(u2,t2)、……(un,tn) And substituting the undetermined equivalent rain intensity function, thereby determining the values of n fitting parameters.
Preferably, in the duration of rainfall, the time-varying scene of the equivalent rain intensity u of the fighting time t is obtained according to the equivalent rain intensity function and the value of the fighting time t.
Preferably, the method further comprises the following steps:
step S3: in the continuous period of rainfall, obtaining instant rainfall h according to the instant rainfall function and the value of the bucket duration t;
step S4: and obtaining the total rainfall H according to the values of all the instant rainfall H in the total rainfall statistical period.
Preferably, the dump bucket rainfall sensor comprises: the water bearing device comprises a water bearing device, a funnel arranged below the water bearing device, a tipping bucket arranged below the funnel, magnetic steel driven by the tipping bucket, and a counting circuit module comprising a reed switch; the bucket time length t is the time interval between two adjacent switch pulses generated by the reed switch.
Preferably, the counting circuit module is provided with a clock circuit; the bucket time t is obtained through the time interval of two adjacent times of trigger of the reed switch, and an accurate value is calculated through a clock signal provided by a clock circuit arranged in the counting circuit module.
Preferably, in step S4, the total rainfall H is obtained by calculating the number of switching values received by the monitoring terminal from the dump bucket rainfall sensor, and the switching values are obtained by the instantaneous rainfall H and the precision epsilon of the dump bucket rainfall sensor.
Preferably, the switching value is obtained by dividing the accumulated value of the instant rainfall h by the precision epsilon of the tipping bucket rainfall sensor or by dividing the accumulated value of the instant rainfall h by the precision epsilon of the tipping bucket rainfall sensor.
Preferably, in step S3: and electronic signals generated by opening and closing the reed switch each time are transmitted to the monitoring terminal in real time, and the value of the bucket time t is obtained by calculation at the monitoring terminal.
The invention and the optimized scheme thereof subvert the existing method for obtaining rainfall data by the tipping bucket type rainfall sensor, break the conventional effect that the error is smaller under the condition of higher precision, introduce the acquisition of the time interval of two times of tipping bucket overturning under the condition of not changing the main body component of the conventional tipping bucket type rainfall sensor, and construct a brand-new solution for obtaining the accurate rainfall by combining the characteristic attributes of the tipping bucket type rainfall sensor. The method completely surpasses the methodology of analyzing and eliminating the error of the tipping bucket type rainfall sensor in the prior art.
Meanwhile, the scheme provided by the invention also provides two feasible schemes without changing the conventional equipment or adjusting the conventional monitoring terminal, does not increase excessive cost, has strong compatibility and obvious effect, is suitable for large-scale popularization and use, and has very high market value and social effect.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
FIG. 1 is a schematic diagram of basic constitutional units and modules required for realizing embodiment 1 of the present invention;
FIG. 2 is a schematic cross-sectional view of a detailed structure of embodiment 1 of the present invention;
FIG. 3 is a perspective exploded view of a concrete structure of example 1 of the present invention;
FIG. 4 is a perspective view of a counter swing mechanism according to embodiment 1 of the present invention;
FIG. 5 is a schematic circuit diagram of a counting circuit module 1 according to an embodiment of the present invention;
FIG. 6 is a schematic circuit diagram of a counting circuit module of embodiment 1 of the present invention 2;
FIG. 7 is a schematic circuit diagram of a counting circuit module according to embodiment 1 of the present invention;
FIG. 8 is a schematic diagram of basic constitutional units and modules required for realizing embodiment 2 of the present invention;
FIG. 9 is a schematic diagram of a rainfall calibrator suitable for testing in accordance with an embodiment of the present invention;
FIG. 10 is a graph of h-t correlation obtained by an embodiment of the present invention;
FIG. 11 is a graph of the u-t correlation obtained by an embodiment of the present invention;
in the figure: 1-rain bearing device; 2-a scaffold; 3-a funnel; 4-tipping bucket; 5-counting the swing mechanism; 6-a counting circuit module; 7-adjusting the screw; 8-magnetic steel; 21-skip position limiter; 22-counting oscillating mechanism limit pieces; 41-tipping bucket rotating shaft; 42-left bucket chamber; 43-right bucket chamber; 51-counting swing mechanism rotating shaft; 52-a projection; 53-relief portion; 54-pointer part; 61-reed pipe; 62-an output terminal; 63-counting circuit module support; 64-a battery; 65-a clock circuit; 66-a main control chip; 67-programming the debug interface; 68-indicator light circuit; 69-a photocoupler; 610-antistatic protection circuit; 611-USB interface; 612-a power supply circuit; 613-power decoupling filter circuit; 100-a housing; 200-base.
Detailed Description
In order to make the features and advantages of the present invention comprehensible, 2 embodiments accompanied with figures are described in detail as follows:
the basic gist of the present invention is: the time interval (bucket duration t) of two-time overturning of the tipping bucket is collected, and the accurate total rainfall H is directly obtained by combining the correlation characteristics of the tipping bucket type rainfall sensor and the bucket duration t. The correlation characteristic of the tipping bucket rainfall sensor and the bucket duration t is one of characteristic attributes of the tipping bucket rainfall sensor. Characteristic attributes of the dump bucket rain sensor exist based on a specific dump bucket rain sensor, and can be used for describing the characteristics of the dump bucket rain sensor which are different from other dump bucket rain sensors, such as: the characteristic that the left and right tipping buckets can turn over when receiving a certain amount of rainwater, the characteristic that how much time is needed for reaching a stable state from turning beginning to turning ending, the characteristic of the total bucket number under a specific total rainfall and a specific constant rainfall and the like, and the correlation characteristic of the tipping bucket type rainfall sensor and the bucket duration t is a general name of the characteristic attribute which can be obtained and determined by the tipping bucket type rainfall sensor according to the bucket duration t. That is, based on the scheme of the present invention, after a specific dump-bucket rainfall sensor (including the insight of its characteristic attributes) is determined, in a rainfall scene, only the duration t of the dump bucket needs to be measured, and the accurate total rainfall H can be obtained.
In the invention, the correlation characteristic of the tipping bucket rainfall sensor and the bucket duration t is characterized by an instant rainfall function J (H, t) being 0, and the total rainfall H can be obtained through the instant rainfall H.
In the present invention, for the definition of the instantaneous rainfall h: the equivalent rain intensity of the bucket time t is in terms of the amount of rainfall produced within the bucket time t. Wherein for "equivalent rain intensity":
let us consider that in the environment of natural rainfall, when the time point is x, the rainfall intensity is R (x), and then
Thus, the exact amount of rainfall over the bucket duration t can be expressed as:
based on the fundamental design principle of the tipping bucket type rainfall sensor, the rainfall change condition within the bucket time t cannot be obtained by the measurement of the tipping bucket type rainfall sensor, so that the integral type cannot be used for obtaining an accurate solution. However, due to the objective presence of accurate rainfall over the bucket duration t, according to the median theorem of integrals: there must be a certain rain intensity value
Satisfy the requirement of
Although the rain intensity value
Nor is it available, but we have thus obtained the original meaning of "equivalent rain intensity".
In the invention, the equivalent rain intensity is defined as the rain intensity value which is uniquely corresponding to each bucket time length value obtained by the determined tipping bucket type rain sensor under the condition of constant rain intensity, so that the fundamental basis of calculating the rainfall in the bucket time length t is obtained. This means that after the form of the instantaneous rainfall function is determined, the rainfall in each bucket time period t can be approximately obtained directly through the bucket time period t, so as to achieve the purpose of directly obtaining the total rainfall H.
It should be noted that the implementation of the solution of the present invention does not depend on a dump-bucket rain sensor of a specific structure, and the requirements of the dump-bucket rain sensor device as a material basis for data measurement are only that: the method can obtain a t value (the t value of a common tipping bucket type rainfall sensor can be obtained by measuring the time interval between two adjacent switch pulses generated by a reed switch), and has certain relativity between the instant rainfall h and the bucket duration t, namely h-t related characteristic attributes (for example, certain tipping bucket type rainfall sensors provided with an upper tipping bucket and a lower tipping bucket for eliminating errors generated by dynamic loss have no determined relativity with the instant rainfall h or equivalent rainfall intensity due to the structural characteristics of the device, so the method is not in the applicable range of the scheme of the invention). Therefore, in a general case, it can be understood that any dump bucket rainfall sensor (which can be generally considered as a dump bucket rainfall sensor with t decreasing trend along with the increase of real-time rainfall intensity and only one dump bucket) with different bucket time lengths t capable of reflecting the change of the instant rainfall h can be used as the basis of the method of the present invention. The specific structure or circuit configuration of the following embodiments provided by the present invention is not intended to limit the application scope of the method of the present invention, but is merely a case for facilitating those skilled in the art to better understand a specific implementation of the solution of the present invention.
As shown in fig. 1, in the first embodiment of the present invention, the basic arithmetic unit is located locally in the dump bucket rainfall sensor for the purpose of compatibility between the existing dump bucket rainfall sensor and the docking of the monitoring terminal generally installed in the weather station and the manner of data interaction. The embodiment improves the counting circuit module circuit which only has the function of generating counting pulses for opening and closing the reed pipe 61 in the conventional tipping bucket type rainfall sensor, and a clock circuit 65 serving as a local acquisition t value and a main control chip 66 serving as a data operation and storage core are added in the counting circuit module circuit. The main control chip 66 generates a switching value capable of accurately calculating the rainfall amount after performing operation according to the value t, and transmits the switching value to the monitoring terminal through the output terminal 62.
The following describes in detail the data processing and calculating method adopted by the main control chip 66 in this embodiment and the process of generating the same.
(1) Obtaining u-t correlation features
According to the definition of the main scheme of the present invention, in order to obtain the instant rainfall h, in the case that the bucket time t can be directly obtained, the equivalent rainfall u of the bucket time t can be obtained, so in this embodiment, the characteristic attribute of the dump bucket type rainfall sensor is obtained by a u-t correlation, and the u-t correlation is constructed by the following method:
step S1: under the condition of test environment, different constant rain intensity values are set
Testing the tipping bucket type rainfall sensor, and constructing an equivalent rain intensity function according to a test result:
G(u,t)＝0；
wherein the unit of u is mm/min; t is the bucket duration in units of s.
Wherein u is the equivalent rain intensity of the bucket duration t, and the unit is mm/min; t is in units of s. The term "equivalent rain intensity" in this embodiment means that, in an environment with constant rain intensity, each rain intensity value has a one-to-one correspondence relationship with each bucket duration value, and the equivalent rain intensity is a unique rain intensity value corresponding to the characteristic bucket duration t.
The above steps mean that by controlling a constant rain intensity value
And obtaining a corresponding t value, and expressing the correlation of u-t by an equivalent rain intensity function.
More specifically, the present embodiment provides two paths constructed by equivalent rain intensity functions.
One is a construction mode of a discrete function, and specifically includes:
under the condition of the test environment, a plurality of different conditions are set and are at (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
Then, corresponding t values are measured (a plurality of t values can be measured under a constant rain intensity value (the rain intensity of the test environment can be constant to a level that the t values cannot be distinguished because of being extremely difficult to control actually) and the t values can be determined through an average, a median, maximum likelihood estimation or other reasonable mathematical methods so as to increase the accuracy and the reliability); at this time, the constant rain intensity value corresponding to each t is considered
The equivalent rain intensity of the bucket duration t is obtained, and the mapping corresponding relation between u and t is established according to the equivalent rain intensity;
wherein u ismaxThe rainfall is an extreme value of the rainfall intensity, generally 8mm/min can be taken, and because the rainfall exceeding the extreme value of the rainfall intensity cannot exist under normal conditions, the upper bound value can be flexibly adjusted according to actual needs.
The method can be used in practice as follows: establishing a corresponding relation table of u and t according to the test result, and aiming at the constant rain intensity value
Is selectedThe conventional fixed ratio point dividing mode can be adopted, and any reasonable other rules can be adopted as long as the point selection density of u can meet the precision requirement of the corresponding relation table, and the data coverage at the interval boundary is considered.
The construction mode has the advantages of being directly available and guaranteeing the accuracy of the u-t correlation under the condition that the density and the distribution of the test points are reasonable enough.
The second is a construction mode of a continuous (fitting) function, and the specific operation thought can be as follows:
by observing and researching the distribution and the form of a large number of discrete points of u-t, the method is constructed with the aim of fitting: in u e (0, u)max]T > 0, and when u is a continuous functionα＜uβSometimes there is tα≥tβThe equivalent rain intensity function of the basic requirement of (1).
The equivalent rain intensity function can be pre-constructed by presetting a function analytic expression comprising n (n is more than or equal to 2) fitting parameters (the more the number of the fitting parameters is, the more the fitting effect is accurate, but the more the calculation amount is generally larger). The pre-constructed analytic expression form is generally obtained by fitting an image formed by distribution of a large number of test values, and the distribution of the test values of the tipping bucket rainfall sensor adopting similar structure and principle generally has common characteristics and rules, so the pre-constructed functional analytic expression is common to the same type of tipping bucket rainfall sensors, as shown in fig. 11, the curve is a coordinate graph of the u-t correlation curve of the tipping bucket rainfall sensor adopted in the embodiment, and the pre-constructed equivalent rainfall function can be based on fitting of the curve.
Setting n different numbers of the samples to be at (0, u) under the condition of the test environmentmax]Constant rain intensity value of interval
At each constant rain intensity value, the corresponding t value is measured (multiple t values can be measured at one constant rain intensity value and can be determined by means of an average, median, maximum likelihood estimation or other reasonable mathematical methods to increase accuracy and confidence)Obtaining n different sets of test values (u)1,t1)、(u2,t2)、……(un,tn) And introducing the equivalent rain intensity function to be constructed in advance, thereby determining the values of the n fitting parameters.
Thereby completing the determination of the analytic expression of the equivalent rain intensity function.
It should be noted here that, although the pre-constructed function analytic expression is generally preferred to adopt a function form which is easy to solve so as to reduce the amount of calculation. However, even if the constructed function analytic expression cannot solve the exact solution of the fitting parameter by the method, the function analytic expression can obtain an approximate value by a computer program, and therefore, the method also belongs to a feasible scheme.
Compared with the former method of constructing a discrete function, the method of constructing a continuous function has the advantages that in the case of the analytic determination of a pre-constructed function, the required test times are generally less for obtaining the correlation of u-t with the same precision, and the satisfactory output value can be obtained by fitting the correlation data which is difficult to be directly measured by tests and close to 0.
Meanwhile, the accuracy of the constructed continuous function can be verified or corrected in a test mode, and the rationality of the constructed function can also be verified through the inherent characteristics of the correlation of u-t, for example, when u approaches to zero, t is generally required to have the property approaching infinity.
Although the above two construction methods do not depend on mathematical modeling and analysis of the tipping bucket type rainfall sensor, the construction method based on the u-t correlation provided by the embodiment does not exclude that a model of an available function analytic formula is derived through a mathematical model established by the tipping bucket type rainfall sensor, and the composition of the equivalent rainfall function is finally determined through a test method.
(2) Selection of output mode
Obtaining the instant rain intensity.
According to the constructed equivalent rain intensity function, under the actual use state of the tipping bucket type rainfall sensor, the equivalent rain intensity value of the bucket duration t can be directly obtained according to the value of the bucket duration t.
If the constructed discrete function is a discrete function, a u value corresponding to a t value closest to an actually measured t value can be directly taken as an output value on a corresponding relation table of u and t; for the continuous function, the actually measured t value is directly substituted into the analytical expression to obtain the corresponding u value as an output value.
If all the obtained equivalent rain intensity values u are represented on the time axis, a quite accurate and real-time picture capable of reflecting the instant rain intensity situation is obtained, and the change situation of the actual rain intensity along with the time can be quantitatively known, which can not be realized by the prior art.
And acquiring the total rainfall.
The definition of the instant rainfall h according to the scheme of the invention:
wherein the unit of the instant rainfall h is mm.
Therefore, according to the relation and the equivalent rain intensity function, the functional relation between the instant rainfall h and the fighting duration t can be directly obtained:
J(h,t)＝0。
the constructed h-t correlation is generally shown in the graph of FIG. 10.
Therefore, in the actual use state of the tipping bucket type rainfall sensor, the instant rainfall h can be obtained directly according to the value of the bucket duration t.
Since the rainfall intensity of actual rainfall in the natural world is basically impossible to be a constant value even within a bucket duration, the total rainfall H obtained by accumulating all instant rainfall H within the whole rainfall statistic period is substantially an approximate operation similar to integral, however, according to the characteristic, the bucket duration t under the same rainfall intensity is shorter as the precision of the tipping bucket type rainfall sensor is higher, and according to the common knowledge, the rainfall intensity change of natural rainfall is naturally less obvious within a shorter time, and the approximate calculation error of the total rainfall H obtained by accumulating all instant rainfall H within the whole rainfall statistic period is smaller. The characteristic is completely opposite to the existing scheme of calculating rainfall through a tipping bucket type rainfall sensor, is obviously better, and is equivalent to directly obtaining a technical path for realizing ultrahigh-precision rainfall data acquisition.
Specifically, as for how to directly obtain the total rainfall H in the total rainfall statistic period through the instant rainfall H, it is the most ideal way that the skip bucket type rainfall sensor directly outputs each calculated instant rainfall H or the total rainfall H in one rainfall period, and in order to be compatible with the existing rainfall acquisition system, this embodiment provides two technical implementation paths of redefined switching quantities calculated and obtained from the counting circuit module by dividing the instant rainfall H and the precision epsilon of the skip bucket type rainfall sensor:
one of them is that: the method is characterized in that the method is obtained by dividing an accumulated value of the instant rainfall h by the precision epsilon of the tipping bucket type rainfall sensor, namely in a total rainfall statistic period, a counting circuit module performs division operation on the accumulated value of the instant rainfall h and the precision epsilon of the tipping bucket type rainfall sensor in a preset period, the obtained divisor is summed with the mantissa of the previous period, then the integer part of the sum is converted into metering signals with the same number to be used as the switching value z to perform periodic batch output, and the decimal part is used as the mantissa of the period.
The second is that: the real-time rainfall h is obtained by accumulating after being divided by the precision epsilon of the tipping bucket rainfall sensor, namely in the total rainfall statistic period, the counting circuit module divides each real-time rainfall h by the precision epsilon of the tipping bucket rainfall sensor, takes an integer part as the switching value z output, accumulates a decimal part, converts the integer part of an accumulated value into the switching value z output with the same number, and simultaneously keeps the decimal part of the accumulated value to participate in the next accumulation.
The real-time rainfall H obtained through local calculation can be accurately obtained through the two paths in a manner of being compatible with the rainfall obtaining and calculating of the existing monitoring terminal, so that the monitoring terminal can obtain the accurate total rainfall H. Although the present embodiment provides the data signal sent locally to the monitoring terminal in the form of the switching value, the switching value generated by the prior art solution is completely based on the counting signal of the reed switch 61, and the switching value generation mechanism of the present embodiment is completely different as described above.
And ③ a mixed output mode.
It can be seen from experiments and correlation analysis that, as shown in fig. 11, when u is extremely small, t is a large value, and the rate of change of t is very high in the interval where u approaches 0. According to the relation, the coincidence of the equivalent rain intensity function constructed by the scheme provided by the embodiment and the actual situation can be hardly guaranteed. In general, the error of the rainfall calculated by the counting signal of the reed switch 61 and the preset measuring range is smaller as the rainfall intensity value is smaller according to the characteristics of the dump bucket type rainfall sensor.
Therefore, based on the basic scheme proposed by this embodiment, a new hybrid output scheme can also be proposed by combining the switching value generation mechanism proposed by this embodiment with the conventional switching value generation mechanism (generating the switching values directly according to the bucket number): a threshold value of t is preset, when the threshold value is smaller than the threshold value, the current rainfall condition deviates from an interval in which u approaches to 0, at the moment, the switching value generation mechanism provided by the embodiment is adopted for calculation and output, and when the threshold value is larger than the threshold value, the traditional switching value generation mechanism is directly adopted, and accurate rainfall data output can also be ensured.
Because the specific test that this embodiment provided the scheme corresponding is based on invariable rain intensity environment, can't reach ideal experimental environment through the rainfall calibrator that currently commonly uses. This is due to the fact that the conventional rainfall calibrator uses a standard ball as a water source container with a given total rainfall H0The rainfall sensor is simulated to rain, the water level in the standard ball is gradually reduced along with the test, so that the pressure difference between the water level in the standard ball and the water outlet is gradually reduced, the method for controlling the rainfall intensity is generally to change the method for changing the area of the water outlet through hole through the flow control valve, and for the constant area of the water outlet through hole, obviously, the flow is reduced along with the reduction of the pressure, namely, the rainfall intensity is gradually reduced.
As shown in fig. 10, the embodiment provides a new design scheme of a rainfall calibrator capable of outputting precise constant rainfall intensity, which includes a water storage container, during testing, a water pump always injects water into the water storage container, the injected water flow is greater than the water outlet flow, more water flows out from an overflow port, then the height difference between the water outlet and the highest water level of the water storage container remains unchanged, so that for a constant water outlet through hole area, the flow is stable, that is, the rainfall intensity is constant, and then the magnitude of the output rainfall intensity can be precisely controlled and adjusted through a stepping motor and a flow control valve.
By using the device, in the test of the construction of the u-t correlation, the bucket time length t can be obtained without measuring and calculating the interval time of two overturning of the tipping bucket, and can be obtained by the following method:
step 1: determining a constant rain intensity value at a constant time T0Within seconds, the flow control valve is adjusted to enable water to flow into a measuring cup, and the mass m grams of the water in the measuring cup is weighed, so that the water quality is improved
Step 2: constant rain intensity
Simulating rainfall to the tipping bucket type rainfall sensor, setting a constant bucket number y, measuring the total rainfall time T, and then
And step 3: by adjusting different constant rain intensities
A set of data (u) can be derived1,t1)，(u2,t2)，…，(un,tn)。
The test method combined with the specific device is also an optimal example in the equivalent rain intensity function construction test of the embodiment, and can ensure high test precision, so that the equivalent rain intensity function is ensured to be better matched with the actual characteristics of the tipping bucket type rain sensor, and the precision of the measured rain data in the use process is improved. Meanwhile, the device can be used as a test instrument for calibrating the instant rainfall function of the tipping-bucket type rainfall sensor in the subsequent long-term use process.
To further illustrate a possible implementation mechanism of the method of this embodiment, a specific possible implementation mechanism provided in this embodiment is specifically described below with reference to fig. 1 to 7:
in terms of the structure of the device, as shown in fig. 2 and 3, the entire device of the present embodiment, as a typical dump bucket type rain sensor having a single dump bucket, includes: the water receiver comprises a water receiver 1 arranged above a support 2, a funnel 32 arranged at the top of the support 2, a skip bucket 4 arranged below the funnel 3, a counting swing mechanism 5 arranged below the skip bucket 4, and a counting circuit module 6 comprising a reed switch 61.
The tipping bucket 4 is hinged with the bracket 2 through a tipping bucket rotating shaft 41; the counting swing mechanism 5 is hinged with the bracket 2 through a counting swing mechanism rotating shaft 51; the bucket rotation shaft 41 and the counter swing mechanism rotation shaft 51 are provided on the symmetrical surfaces of the left bucket chamber 42 and the right bucket chamber 43 of the bucket 4.
As shown in fig. 2, the device of the present embodiment is integrally mounted in a housing formed by a case 100 and a base 200, and a counter circuit module 6 is disposed on the side of a holder 2, provided with an output terminal 62 and a battery 61, and integrally assembled on a counter circuit module holder 63.
As shown in fig. 4, the counting and swinging mechanism 5 of the present embodiment includes a protrusion 52 protruding along the extending direction of the left bucket chamber 42 and the right bucket chamber 43, a receding part 53 surrounding the skip rotating shaft 41, and a pointer part 54 fixed with a magnetic steel 8; the highest point of the pointer 54 is as high as the reed switch 61 arranged on the side wall of the support 2 (a scheme slightly lower than the reed switch 61 is also feasible, and only the normally open contact of the reed switch 61 is required to be closed when the pointer 54 is at the highest point of the swing, and the normally open contact of the reed switch 61 is required to be opened when the pointer 54 deviates from the highest point); the magnetic steel 8 is arranged on the symmetrical surface of the counting swing mechanism 5.
The swinging ranges of the two sides of the dump bucket 4 and the counting swinging mechanism 5 are respectively limited by two limiting parts, including two dump bucket limiting parts 21 shaped like cylindrical protrusions and two counting swinging mechanism limiting parts 2222 shaped like cylindrical protrusions; the limiting part is used for controlling the maximum swinging range of the tipping bucket 4 and the counting swinging mechanism 5, so that the path of each overturning is controllable.
Furthermore, the form of the counter swing mechanism 5 needs to satisfy: when the counting and swinging mechanism 5 is at any angle within the allowable swinging range, the path along which the dump bucket 4 swings towards two sides intersects with the protruding part 52 of the counting and swinging mechanism 5, so that each overturning and swinging of the dump bucket 4 can correspondingly drive the counting and swinging mechanism 5 to swing, and the magnetic steel 8 can trigger the swinging of the reed pipe 61 to complete one counting.
Meanwhile, the gravity center of the tipping bucket 4 is higher than the tipping bucket rotating shaft 41; the gravity center of the counting swing mechanism 5 should be higher than the rotating shaft 51 of the counting swing mechanism to avoid the situation that the state change of the reed pipe 61 cannot be triggered because the magnetic steel 8 swings repeatedly near the reed pipe 61.
The above components mainly adjust the counting assembly composed of the reed pipe 61 (magnetic reed switch) and the magnetic steel 8, except for the most basic necessary components of the conventional dump-bucket rainfall sensor. The scheme of the embodiment arranges the magnetic steel 8 on the counting swing mechanism 5 structurally separated from the tipping bucket 4, thereby eliminating the error caused by the influence of the magnetic force generated when the magnetic steel 8 is close to the reed pipe 61 on the whole moment of the device. When the skip bucket 4 turns over and the skip bucket 4 chamber on the rain-bearing side drops, the corresponding one-side protruding part 52 acts on the bottom of the skip bucket 4 chamber, and the kinetic energy of the drop bucket 4 chamber drives the counting swing mechanism 5 to swing, so that the magnetic steel 8 arranged on the pointer part 54 swings and passes through the near point of the reed switch 61, and the triggering of the magnetic reed switch can be completed under the condition of not influencing the moment of the skip bucket 4.
It should be noted that, in the conventional dump bucket type rain sensor, the magnetic steel 8 only needs to be set on the counting swing mechanism 5 and the pointer part 54 thereof as described in the device scheme of this embodiment, but only needs to be set on the magnetic steel 8 to swing to a certain characteristic point, which can trigger the normally open contact of the reed pipe 61 to close, and when the magnetic steel 8 deviates from the characteristic point, the normally open contact of the reed pipe 61 is opened, and of course, the specific setting mode of the reed pipe 61 can be flexibly adjusted to match the specific setting position of the magnetic steel 8.
Preferably, in the present embodiment, the dump body 4 is further provided with an adjusting screw 7 capable of adjusting the center of gravity perpendicular to the dump body rotating shaft 41, and the adjusting screw 7 is capable of linearly adjusting the center of gravity of the combined body of the dump body 4 and the adjusting screw 7 according to the disclosure of chinese patent publication No. CN 107765349A. And the rain bearing surface of the tipping bucket 4 is a cylindrical surface. In this preferred structure, the adjusting screw 7 should be disposed inside the pointer 54 to ensure that the distance between the magnetic steel 8 and the reed switch 61 is not too large to trigger the reed switch 61.
In terms of device circuits, as shown in fig. 5 to 7, the main control chip 66 as a control, storage and operation core adopts SMT32L051C8, which is connected to the clock circuit 65, the programming and debugging interface 67, the reed pipe 61, the indicator lamp circuit 68, the photocoupler 69, the power supply circuit 612, the anti-static protection circuit 613 and the USB interface 611, respectively.
The reed switch counting circuit formed by the reed switch counting circuit is matched with magnetic steel 8 driven by the swinging of the tipping bucket 4 in the tipping bucket type rainfall sensor, when the tipping bucket 4 is overturned to a preset position, the distance between the magnetic steel 8 and the reed switch 61 is nearest, so that a normally open switch of the reed switch 61 is closed and conducted under the action of a magnetic field of the magnetic steel 8, and when the magnetic steel 8 moves continuously and is slightly far away from the reed switch 61, the influence of the magnetic steel on the magnetic field of the reed switch 61 is weakened, and the normally open switch of the reed switch 61 is disconnected. The pulse generated by the opening and closing of the reed switch 61 can be used as the counting basis of the overturning times of the tipping bucket.
The clock circuit 65, which is an important component implemented in the present embodiment, is composed of a crystal oscillator, a crystal oscillation control chip, and a capacitor, and is provided for the purpose of measuring and measuring the time interval (bucket length) between two adjacent triggerings of the reed switch 61.
The main control chip 66 undertakes data storage and calculation in the process of acquiring more accurate rainfall data, on one hand, the instant rainfall can be calculated through a preset instant rainfall function and the bucket duration, and then the output switching value is obtained through the accumulation of the instant rainfall and the division calculation of the precision of the tipping bucket rainfall sensor.
In the present embodiment, the switching amount transmitted to the precipitation amount monitoring terminal is output from the output terminal 62 via the photocoupler 69. The output mode can be replaced by a wireless signal transmission mode, so that the switching value output by the tipping bucket rainfall sensor does not need to be transmitted through a specific line.
In order to better achieve the effect of accurate calculation of the main control chip 66, the embodiment provides the USB interface 611 capable of directly performing data interaction with the rainfall calibrator or the upper computer, so as to achieve acquisition of output data of the rainfall sensor or parameter update, and the programming and debugging interface 67 capable of downloading and obtaining the accurate calibration program, where the program language converted by the method of the embodiment and the corresponding parameter value thereof can be downloaded to the local or updated through the port. An anti-static protection circuit 610 is disposed between the USB interface 611 and the main control chip 66 to ensure the overall security of the circuit system.
The power circuit 612 of this embodiment is a 1.8V power supply voltage stabilizing circuit, and is powered by a 8000 ma battery 64, and is also provided with a power decoupling filter circuit 613 to enhance the stability of the power supply. The large-capacity battery can be matched with low-power consumption chips and devices, so that the device can work for a long enough time (years) without charging.
An indicator light circuit 68 is also provided for indicating the state of charge of the power supply.
In contrast, in the second embodiment of the present invention, since the design concept is based on the consideration of the existing dump-bucket rain sensor device, it is not required that the dump-bucket rain sensor device has a specially designed counting circuit module as shown in fig. 5-7 of the first embodiment, and the basic device conditions only need to satisfy the basic structure of the existing dump-bucket rain sensor as shown in fig. 8.
In this embodiment, the task of obtaining the value of the bucket duration t and calculating the total rainfall according to the instant rainfall function is executed at the monitoring terminal, and the electronic signal generated by the reed switch of the local tipping bucket type rainfall sensor is transmitted to the monitoring terminal in real time. At this time, the monitoring terminal can restore the bucket duration corresponding to the tipping bucket type rainfall sensor through the time interval between two adjacent electronic signals, and then the bucket duration is calculated through the method provided by the embodiment. (of course, the determination of the instant rainfall function must be performed locally, and only the determined characteristic function can be placed in the monitoring terminal to calculate the total rainfall according to the duration of the bucket)
The realization idea has the advantages that the construction of the instant rainfall function can be completed only by locally testing the tipping bucket type rainfall sensor without basically changing the hardware of the tipping bucket type rainfall sensor of the existing rainfall collection point (which is not suitable for the double-tipping bucket type rainfall sensor).
Accordingly, however, with this solution, the existing monitoring terminal needs to be modified, and the measuring and calculating precision time and the corresponding device or calculation program for performing the solution calculation need to be increased.
Finally, it should be specifically noted that although the 2 embodiments provided above all convert the acquisition scheme of the bucket duration (the time interval of two-time overturning of the dump bucket) into: and acquiring the time interval between two adjacent switching pulses generated by the reed switch. However, in the solution of the present invention, the obtaining manner of the bucket duration is not limited by the specific device combination of the reed switch 61 and the magnetic steel 8, and the bucket duration can be obtained by using a plurality of other proximity switches or contact switches similar in principle, such as an infrared sensor, a contact sensor, and the like, and the solution of using the reed switch 61 and the magnetic steel 8 in the above 2 embodiments is only because the solution is a common solution of the current tipping bucket type rain sensor, and the use effect is more superior because no additional power supply is required.
The present invention is not limited to the above preferred embodiments, and all other various methods for obtaining accurate rainfall data based on equivalent rainfall intensity can be obtained from the present invention.
Claims (9)
1. A method for obtaining accurate rainfall data based on equivalent rainfall intensity is characterized in that: the rain sensor based on the tipping bucket comprises the following steps:
step S1: under the condition of test environment, different constant rain intensity values are set
Testing the tipping bucket type rainfall sensor, and constructing an equivalent rain intensity function according to a test result:
G(u,t)＝0；
wherein the unit of the equivalent rain intensity u of the bucket time length t is mm/min; the bucket duration t is the time interval of two overturning of the tipping bucket, and the unit is s;
step S2: according to the equivalent rain intensity function and
obtaining an instant rainfall function:
J(h,t)＝0；
wherein the instant rainfall h is the rainfall generated by the equivalent rainfall intensity of the bucket duration t within the bucket duration t;
in step S1, the specific method for testing the dump bucket rainfall sensor and constructing the equivalent rain intensity function according to the test result is as follows:
under the condition of the test environment, a plurality of different conditions are set and are at (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
Then, measuring a corresponding t value; and establishing a mapping corresponding relation between u and t;
wherein u ismaxIs an extreme value of rain intensity.
2. The method for obtaining accurate rainfall data based on equivalent rainfall intensity according to claim 1, wherein in step S1, the dump box rainfall sensor is tested, and the specific method for constructing the equivalent rainfall intensity function according to the test result is as follows:
under the condition of the test environment, a plurality of different conditions are set and are at (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
And measuring a corresponding t value, and obtaining an undetermined equivalent rain intensity function in a fitting mode according to a test result:
the undetermined equivalent rain intensity function comprises n fitting parameters, wherein n is more than or equal to 2, and the values of the fitting parameters are obtained by the following method:
under the condition of the test environment, n different ones are set to be (0, u)max]Constant rain intensity value of interval
At each constant rain intensity value
Then, the corresponding t value is measured to obtain n groups of different values (u)1,t1)、(u2,t2)、……(un,tn) And substituting the undetermined equivalent rain intensity function, thereby determining the values of n fitting parameters.
3. The method for obtaining accurate rainfall data based on equivalent rainfall intensity according to any one of claims 1-2, wherein: and in the continuous period of rainfall, obtaining a scene of the change of the equivalent rainfall u of the fighting time t along with the time according to the equivalent rainfall function and the value of the fighting time t.
4. The method for obtaining accurate rainfall data based on equivalent rainfall intensity according to any one of claims 1-2, further comprising:
step S3: in the continuous period of rainfall, obtaining instant rainfall h according to the instant rainfall function and the value of the bucket duration t;
step S4: and obtaining the total rainfall H according to the values of all the instant rainfall H in the total rainfall statistical period.
5. The method for obtaining accurate rainfall data based on equivalent rainfall intensity of claim 4, wherein: the tipping bucket rainfall sensor comprises: the water bearing device comprises a water bearing device, a funnel arranged below the water bearing device, a tipping bucket arranged below the funnel, magnetic steel driven by the tipping bucket, and a counting circuit module comprising a reed switch; the bucket time length t is the time interval between two adjacent switch pulses generated by the reed switch.
6. The method for obtaining accurate rainfall data based on equivalent rainfall intensity according to claim 5, wherein: the counting circuit module is provided with a clock circuit; the bucket time t is obtained through the time interval of two adjacent times of trigger of the reed switch, and an accurate value is calculated through a clock signal provided by a clock circuit arranged in the counting circuit module.
7. The method for obtaining accurate rainfall data based on equivalent rainfall intensity of claim 6, wherein: in step S4, the total rainfall H is obtained by calculating the number of switching values received by the monitoring terminal from the dump bucket rainfall sensor, and the switching values are obtained by the instantaneous rainfall H and the precision epsilon of the dump bucket rainfall sensor.
8. The method for obtaining accurate rainfall data based on equivalent rainfall intensity of claim 7, wherein: the switching value is obtained by dividing the accumulated value of the instant rainfall h by the precision epsilon of the tipping bucket rainfall sensor or by dividing the accumulated value of the instant rainfall h by the precision epsilon of the tipping bucket rainfall sensor.
9. The method for obtaining accurate rainfall data based on equivalent rainfall intensity according to claim 5, wherein: in step S3: and electronic signals generated by opening and closing the reed switch each time are transmitted to the monitoring terminal in real time, and the value of the bucket time t is obtained by calculation at the monitoring terminal.
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| CN103018794A (en) * | 2012-10-26 | 2013-04-03 | 浙江大学 | Device for improving measurement accuracy and measurement reliability of single-tipping-bucket rain gauge and use method for same |
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