CN108267800B - High-precision water surface evaporation capacity monitoring method - Google Patents
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Abstract
The invention discloses a high-precision water surface evaporation capacity monitoring method, which overcomes the defects of errors caused by acquisition lag, unstable liquid level and overlarge rainfall of the conventional evaporation device. The method divides each day into a plurality of monitoring time periods, and takes the starting time point of each monitoring time period as an acquisition point; the water level in the evaporation device is collected at a collection point, and the calculation error of the evaporation capacity can be reduced by means of taking rainfall in advance and obtaining data after the rainfall is finished and the water level balance is finished after the water replenishing is finished; the opening and closing time of the valve is controlled through calculating the height of the liquid level and the time required by water supplement and overflow, the closing time of the valve is accurately controlled, and the liquid level of the evaporation monitoring device is kept stable; the active overflow mode is adopted, so that the accumulated error can be eliminated, and the accuracy is improved; through the abnormal data filtering mode, abnormal data with defects are further eliminated, and the data accuracy and the reasonability are improved.
Description
Technical Field
The invention belongs to the technical field of hydrological and meteorological monitoring, and relates to a high-precision water surface evaporation capacity monitoring method.
Background
The water surface evaporation capacity is an important index for observing hydrology and water resources and weather in China, and a key problem is how to accurately monitor the evaporation capacity. The existing automatic evaporation station measures the change of the liquid level height every day through a measuring needle to calculate the evaporation capacity, and actively supplements water to make up the lost water in the evaporation device, and when the water surface rises, the excessive water flows out through an overflow port to ensure that the liquid level in the evaporation device is not too high. Under the structure of the existing device, because a large amount of water is always stored in the overflow pipe, the calculation of the overflow amount is not accurate, and because the water level change modes are various, the water amount in the overflow pipe cannot be accurately calculated, so that the calculation of the evaporation amount has large errors.
The applicant has previously applied an improved automatic monitoring device (application number 2016212862494) for water surface evaporation capacity, which adopts active overflow and automatic water replenishing to minimize the occurrence of passive overflow, thereby effectively avoiding overflow metering errors. However, in the using process, the following problems are still found:
1. because the mode of replacing an overflow sensor and a barrel connecting pipe with active overflow can cause the problem of lagging water level collection after overflow or water supplement.
2. During rainfall, the liquid level of the measuring well and the liquid level of the evaporation barrel are unstable, so that the calculation error of the evaporation amount can be caused.
3. The active water replenishing and the active overflow are carried out in the evaporation barrel and are completed through the opening and closing of the ball valve. When the valve was opened completely, rivers were too fast, and it is unable to realize to gather through the liquid level and come accurate control valve closing time. In addition, the flow rate of active water replenishing and overflowing is too high, and the stability of the liquid level of the evaporation monitoring device is influenced.
4. When heavy rain is strong, the error of the evaporation capacity caused by the increase of the error of the rain gauge is increased.
Disclosure of Invention
In order to solve the problems, the invention discloses a high-precision water surface evaporation capacity monitoring method, which overcomes the defects of errors caused by acquisition lag, unstable liquid level and overlarge rainfall of the conventional evaporation device.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides a high-precision water surface evaporation capacity monitoring method, which comprises the following steps:
step one, dividing each day into a plurality of monitoring time intervals, taking the starting time point of each monitoring time interval as an acquisition point, and dividing each monitoring time interval into a plurality of small time units;
when the liquid level of the first collection point exceeds an overflow line or is lower than a water replenishing line, overflowing or water replenishing occurs, judging whether rainfall exists in each time unit or not after the first collection point and the time unit, and when the rainfall does not exist, taking the reference rainfall as the rainfall before the time unit; if the rainfall exists, continuously judging the rainfall condition of the next time unit until no rainfall is judged, wherein the reference rainfall is the rainfall before the time unit, and the reference water level is the rear water level of the first time unit without rainfall after water replenishing and overflowing;
when the liquid level of the first collection point is not more than the overflow line and not less than the water replenishing line, whether rainfall exists in the previous time unit is judged:
if no rainfall exists, taking the rainfall before the time unit according to the reference rainfall, and taking the water level after the time unit according to the reference water level;
if the rainfall exists, judging whether the rainfall exists in the next time unit or not after the first acquisition point, if the rainfall does not exist, calculating the reference rainfall as the rainfall before the time unit, and taking the reference water level as the rear water level of the first time unit without the rainfall after the first acquisition point;
collecting water levels in the evaporation device at other collection points, and when the liquid level of the collection point exceeds an overflow line, overflowing occurs: judging whether rainfall exists in each time unit after the collection point and the time unit, and taking the reference rainfall as the rainfall before the time unit when the rainfall does not exist; if the rainfall exists, continuously judging the rainfall condition of the next time unit until no rainfall is judged, wherein the reference rainfall is the rainfall before the time unit, and the reference water level is the rear water level of the first time unit without rainfall after the water replenishing overflow is finished;
if no overflow occurs, directly using the previously set reference rainfall and reference water level, and continuing to the next collection point to execute the step three;
step four, collecting water level at the end time point of each monitoring period as calculated water level, and taking rainfall before the last time unit of each monitoring period as calculated rainfall;
step five, calculating the evaporation capacity of each monitoring period according to the following formula at the end time point of each monitoring period and transmitting the data to a data center:
E＝P+(h1-h2)
h1 is the calculated water level in the step two, h2 is a reference water level, and P is the calculated rainfall-reference rainfall;
and step six, accumulating the evaporation capacity at the collection point where the overflow occurs every time in the day to obtain the total evaporation capacity in the day.
Further, in the fifth step, when the liquid level at the collection point exceeds the overflow line or is lower than the water replenishing line, after water replenishing or overflow occurs, after the evaporation capacity in the period is calculated, whether rainfall exists or not is judged in a time interval from the collection point to the collection point plus compensation, if no rainfall exists, the evaporation capacity in the period is calculated as 8/7, evaporation compensation is performed, and if rainfall exists, evaporation compensation is not performed.
Further, the compensation judgment time is 2 time units.
Further, filtering abnormal values in the sixth step, if there is a rainfall period in the monitoring period and the rainfall is too large and the evaporation amount is too large, filtering data, and excluding an abnormal accumulated value according to the evaporation amount data of the collection point before the next overflow collection point.
Further, in the sixth step, when the evaporation data in a certain monitoring period exceeds the maximum value of normal rainfall, the data is abnormal, data filtering is needed, and an abnormal accumulated value is eliminated aiming at the evaporation data of the collection point before the next overflow collection point.
Further, when rainfall makes the evaporation barrel water level reach the warning line, stop the liquid level monitoring, this period evaporation capacity is zero, monitors again after overflowing until next acquisition point.
Furthermore, the water replenishing or overflowing time required by the unit height is preset, the height difference is calculated by measuring the liquid level when water replenishing or overflowing is required, and the specific time required by water replenishing and overflowing is calculated, so that the opening and closing time of the valve is controlled, and the reference liquid level in the evaporation barrel is accurately controlled.
Further, the monitoring time period is 4 hours, the time unit is 15 minutes, the active overflow time is 15 minutes, and the compensation judgment time is 30 minutes.
Compared with the prior art, the invention has the following advantages and beneficial effects:
according to the invention, through the modes of counting rainfall in advance and obtaining data after the rainfall is finished and the water replenishing and overflowing are finished and the liquid level is balanced, the calculation error of the evaporation capacity can be reduced; the opening and closing time of the valve is controlled through calculating the height of the liquid level and the time required by water supplement and overflow, the closing time of the valve is accurately controlled, and the liquid level of the evaporation monitoring device is kept stable; the active overflow mode is adopted, so that the accumulated error can be eliminated, and the accuracy is improved; through the abnormal data filtering mode, abnormal data with defects are further eliminated, and the data accuracy and the reasonability are improved.
Detailed Description
The technical solutions provided by the present invention will be described in detail below with reference to specific examples, and it should be understood that the following specific embodiments are only illustrative of the present invention and are not intended to limit the scope of the present invention.
According to the stipulation of ' SL630-2013 ' water surface evaporation observation standard ' in China, the daily evaporation capacity in the non-ice period is calculated according to the following method:
E＝P-∑hget-∑hOverflow+∑hAdding+(h1-h2) (1)
In the formula: e-daily evaporation, mm
P-daily precipitation, mm
∑hGet-the sum of the water amounts taken out from 8 hours on the previous day to 8 days on the current day, mm
∑hAddingThe sum of the water amount added from 8 hours on the previous day to 8 days on the current day is mm
∑hOverflowThe sum of the overflow water amounts from 8 hours before the day to 8 days at the day, mm
h1，h2The water level of the evaporator, mm, at the last (previous day) and this (current day).
According to the above formula, the automatic water surface evaporator can only really realize the automatic measurement of the evaporation capacity by automatically completing the measurement of each element. The system simplifies the formula, adds the functions of active overflow and active water supplement based on the evaporation capacity monitoring device applied by the applicant in the earlier stage, and can monitor h in the formula (1) through monitoring the water levelGet、hAdding、hOverflowControl is performed to ensure that no water is taken from eight points on the previous day to 8 points on the current day, no measurement of the evaporation amount is performed during water replenishing and overflowing, and the evaporation amount during the water replenishing and overflowing period is replenished with time in the later period. So that the formula can be simplified into
E＝P+(h1-h2) (2)
H1 in the above formula is the water level height after the liquid level is stabilized after the last drainage, also called the reference water level, and h2 is the calculated water level. E is the evaporation before overflow occurs, P is the rainfall, and is obtained by subtracting the reference rainfall from the calculated rainfall. In addition, the invention divides each observation day into a plurality of monitoring periods based on unit time, for example, divides 24 hours of a day into N1 equal monitoring periods, and the time occupied by each monitoring period is T1-24/N1. Dividing T1 into N2 small time units, wherein the time T2 of each small time unit is T1/N2, and T2 time has two requirements: requirement 1, T2 is greater than the settling time of the logging and evaporation throughput levels, which is experimentally determined based on the system configuration. Requirement 2, T2 is greater than the time for the device to actively open the valve to complete active water replenishment and active flooding. Therefore, the time of 2 × T2 can be the liquid level stabilization time after water replenishment or overflow, and therefore the compensation time is 2 × T2. T1 was 4 hours in this example.
The evaporation device is provided with four lines, namely a warning line, an overflow line, a standard line and a water supplementing line, and whether overflow or water supplementation is needed or not is judged by comparing the overflow line with the water supplementing line. The water replenishing or overflowing time required by the unit height is set by adding a manual setting mode, the height difference is calculated by measuring the liquid level, and the specific time required by water replenishing and overflowing is automatically calculated by the device, so that the opening and closing time of the valve is controlled, and the reference liquid level is controlled. After water supplement or overflow is completed, the device collects the liquid level after waiting for the liquid level balance, and records the liquid level as a reference liquid level. In this example, the active water replenishing and overflowing time can be controlled within 15 minutes through the design of a mechanical structure, after the overflowing is finished, after 15 minutes, the liquid level measurement is carried out, namely the T2 is 15 minutes, and each T1 is divided into 8T 2. The compensation time was therefore 2 × T2 ═ 30 minutes. For example, active overflow occurs at 8 points, and then the liquid level is collected at 8 points 30. Calculating the evaporation capacity of 8:30-12:00 to estimate the evaporation capacity of 8: 00-12: stage evaporation amount of 00. Of course, each evaporation station can control the specific time of the active overflow according to the conditions and set. The evaporation device is also provided with a liquid level measuring device and a rain gauge. Both the liquid level measuring device and the rain gauge have a history data recording function so that the invention extracts corresponding data at a desired time point. The evaporation device can also be provided with a processor so as to calculate and display the evaporation amount on site.
The conventional evaporation amount calculation adopts 8 points as a starting point, acquisition points need to be added after the overflow frequency is increased, and the initial water level and the initial rainfall are determined again after the overflow so as to improve the measurement accuracy.
In the embodiment, the initial water level every day is based on 8 points, the water level is read every 4 hours to calculate the evaporation capacity, and the overflow line and the water supplementing line are compared to judge whether overflow or water supplementation is needed. And in the later period, whether overflow is needed or not is judged by reading water level data every 4 hours, if the overflow is needed, the flag bit in the current table is 1, otherwise, the flag bit is 0, and the overflow flag bit at 8 points of the next day is 1 (fixed). If flooding occurs, the evaporation is recalculated.
Specifically, the high-precision water surface evaporation amount monitoring method provided by the invention comprises the following steps:
dividing each day into a plurality of monitoring periods, and taking the starting time point of each monitoring period as an acquisition point; this example will divide each day into 6 time periods, i.e. with 6 acquisition points, each monitoring period being 4 hours. The data collected in each monitoring period are all sent to a data center for calculation and storage, the 4-hour interval is reasonable, the program is too complicated and unstable in liquid level when the time is too short, and the evaporation capacity is easily lost when the time is too long.
And step two, collecting the water level in the evaporation device at a first collection point (the first collection point is 8:00 in the invention), actively overflowing to the outside of the evaporation device when the water level is higher than an overflow line, and actively replenishing water to the inside of the evaporation device when the water level is lower than a water replenishing line. The water replenishing or overflowing is preferably performed when the final water level reaches the standard line.
The invention also judges when the water level and the rainfall are taken as the reference water level according to whether the rain falls or not, thereby avoiding the water level measurement error caused by the water level fluctuation in the water level well due to the rainfall. The rainfall participating in the evaporation calculation was counted fifteen minutes in advance. For example, if the water level is the water level collected at 8 points, the rainfall is 7: 45.
When the liquid level at the 8 point exceeds an overflow line or is lower than a water replenishing line, overflow or water replenishing is carried out, judgment is carried out on whether rainfall exists in a time unit (15 minutes) or not after the first collection point + the time unit (15 minutes including active overflow time) namely after the 8 point 15 overflow or water replenishing is finished, when no rainfall exists in the time unit, the rainfall at that time is taken as the reference rainfall which is the rainfall before the time unit, namely the rainfall at the beginning of the time unit without rainfall; and if the rainfall exists, continuously judging the rainfall condition of the next time unit until no rainfall is judged, and obtaining the reference rainfall which is the rainfall before the time unit. And the reference water level is the rear water level of the first rainfall-free time unit after the water replenishing overflow is finished, namely the water level at the end of the 15-minute rainfall-free time unit.
When the liquid level at the 8 point does not exceed the overflow line and is not lower than the water replenishing line, judging whether rainfall exists in the previous 15 minutes, namely 7:45-8: 00:
if no rainfall is present at 7:45-8:00, the reference rainfall is measured 15 minutes before, namely 7:45 rainfall, and the reference water level is the current water level, namely 8-point water level.
And if rainfall exists at 7:45-8:00, judging whether the rainfall exists within 15 minutes after the first collecting point, namely after 8 points, and if no rainfall exists, taking the rainfall at that time as the reference rainfall, namely the rainfall before 15 minutes. The reference water level is the current water level.
It should be noted that water replenishment is only possible at 8:00-8:30 per day, whereas flooding may occur at the collection point for any observation period. Therefore, whether water is needed to be supplemented or not is judged at the collection points except the first collection point without a water supplementing line.
And step three, collecting the water level in the evaporation device at other collection points, and actively overflowing to the outside of the evaporation device when the water level is higher than an overflow line, wherein the overflow is preferably performed when the final water level reaches a standard line.
When the liquid level of the collection point exceeds the overflow line and overflow occurs, judging whether rainfall exists in the time unit (15 minutes) after the collection point and the time unit (15 minutes) and after the overflow or water supplement is completed, and if the rainfall does not exist, taking the rainfall at that time as the reference rainfall, namely the rainfall before the time unit; and if the rainfall exists, continuously judging the rainfall condition of the next 15 minutes until no rainfall is judged, and obtaining the reference rainfall which is the rainfall before the time unit. And the reference water level is the rear water level of the first rainfall-free time unit after the water replenishing overflow is finished. Namely, when the other collection points after the first collection point overflow due to the fact that the water level is higher than the overflow line, the reference rainfall and the reference water level need to be reset, if the overflow does not occur, the values do not need to be reset, the reference rainfall and the reference water level which are set and completed before are directly used, and the collection points continue to the next collection point.
And step four, collecting the water level at the end time point of each monitoring period as a calculated water level, and taking the rainfall before the last time unit (namely the rainfall at the beginning time point of the last time unit) of each monitoring period as the calculated rainfall.
Different values of the reference rainfall, the reference water level, the calculated water level and the calculated rainfall based on different conditions of water replenishment, overflow and rainfall are explained by way of examples below.
For example: and (3) mixing the components in parts by weight: 00-12: the 4 hours 00 are divided into 16 rainfall time cells, 0 for no rain, 1 for rain reference rainfall and reference water level indicated by dark grey, and the time cells for calculating rainfall and water level indicated by light grey.
A) If the water supplement or overflow happens at 8 points-8: 30
(1) The rainfall condition is as follows
| 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
It can be seen that there was no rainfall between 8 points 15-8:30, and therefore
The reference rainfall is 8-point 15 rainfall, and the reference water level is 8-point 30 water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
(2) The rainfall condition is as follows
| 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
The reference rainfall is 8-point 45 rainfall. The reference water level is 9-point water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
(3) The rainfall condition is as follows
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
The reference rainfall was 11 points 45. The reference water level is 12-point water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
It can be seen that when rain continues, we consider the evaporation amount to be 0.
(4) The rainfall condition is as follows
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
The reference rainfall is 10-point rainfall. The reference water level is 10 o' clock 15 water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
B) If no make-up or overflow occurs at 8 o' clock-8: 30,
(1)7:45-8:00 no rainfall
The reference rainfall is 7-point 45 rainfall, and the reference water level is 8-point water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
(2) Rainfall at 7:45-8:00, and no rainfall after 15 minutes. A reference water level is measured.
| 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 |
The reference rainfall is 8-point rainfall. The reference water level is 8-point 15 water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
(3) The rainfall condition is as follows
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
The reference rainfall was 11 points 45. The reference water level is 12-point water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
(4) The rainfall condition is as follows
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
The reference rainfall is 10-point rainfall. The reference water level is 10 o' clock 15 water level.
The calculated rainfall is 11 points 45 rainfall, and the calculated water level is 12 points water level.
Step five, calculating the evaporation capacity of each monitoring period according to the following formula at the end time point of each monitoring period and transmitting the data to a data center:
E＝P+(h1-h2)
and h1 is the calculated water level in the step two, h2 is the reference water level, and P is the calculated rainfall-reference rainfall.
As an improvement, compensation is made during each calculation period when flooding or water replenishment occurs. When the liquid level of the collection point exceeds the overflow line or is lower than the water replenishing line, water replenishing and overflow are needed in the monitoring time period of the collection point, after the evaporation capacity of the time period is calculated, the judgment of whether rain exists or not is carried out on the time (2 time units, 30 minutes in the example) from the collection point to the collection point and the compensation judgment time, and if rain does not exist, the formula is adopted: the evaporation amount is P + (h1-h2) × 8/7, and evaporation compensation is performed. If rainfall exists, evaporation compensation is not carried out, and the evaporation amount in the time period is calculated. The evaporation amount was calculated as P + (h2-h 1).
And step six, accumulating the evaporation capacity at the collection point where the overflow occurs every time in the day to obtain the total evaporation capacity in the day. The evaporation amount is calculated by using a method of combining the sectional amount and the cumulative amount. In this example, the evaporation amount is calculated by a table look-up method, and the evaporation amount is determined by a table look-up method using the flag bit of the overflow.
For example: overflow occurs at 16 points, and when overflow occurs at 0 point, the data in the storage space is as follows (6 units)
| Collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Amount of evaporation | 0.2 | 0.6 | 0.3 | 0.5 | 0.1 | 0.4 |
| Overflow sign | 0 | 1 | 0 | 1 | 0 | 1 |
In the above table: 0.2 represents the evaporation amount from 8 to 12 points. 0.6 represents the evaporation amount from 8 to 16 points. 0.3 represents the evaporation amount from 16 to 20 points. 0.5 represents the evaporation amount from 16 to 0 points. 0.1 represents the evaporation amount from 0 o ' clock to 4 o ' clock on the following day, and 0.4 represents the evaporation amount from 8 o ' clock on the following day.
Therefore, the daily evaporation rate from 8 o 'clock to 8 o' clock of the next day is 1.5 instead of 0.6+0.5+0.4
And during calculation, judging whether the daily evaporation amount needs to be calculated according to whether the overflow flag bit is 1 or not.
According to the characteristics of evaporation capacity, if the 4-hour time interval quantity has a rainfall period, the rainfall is greater than a certain fixed value, and the evaporation capacity is greater than a certain fixed value, data filtering is carried out, if no overflow occurs in the next monitoring time interval, the abnormal accumulated value is calculated and eliminated comprehensively, wherein the adopted filtering fixed value is different according to different environments of different regions and different stage evaporation capacities, and the basic value can be set manually.
Outlier filtering example one:
p is the previous time period, namely 4 hours of rainfall before the current acquisition point
| Collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Time interval rainfall | P＝1.0 | P＝5.0 | P＝0 | P＝0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 4.1 | 4.5 | 4.8 | 4.9 | 5.0 |
| Overflow sign | 0 | 0 | 0 | 0 | 0 | 0 |
It can be seen that at 16 points, data is abnormal, and in the case where the rainfall is 5.0, it is impossible that the evaporation amount per unit time period is EI4.1-0.2-3.9, the time section is judged to be abnormal, the evaporation capacity of the time section is assigned with 0, and then the evaporation capacity data of the abnormal time section is sequentially subtracted from the evaporation capacity data of each collection point according to the overflow capacity mark. When overflow occurs, we believe that the error is eliminated and the collection point after the overflow collection point does not need to subtract this abnormal period of evaporation data.
The data in the table is filtered and changed to the data with the daily evaporation amount of 1.1
| Collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Time interval rainfall | P＝1.0 | P＝5.0 | P＝0 | P＝0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 0.2 | 4.5-3.9＝0.6 | 4.8-3.9＝0.9 | 4.9-3.9＝1.0 | 5.0-3.9＝1.1 |
| Overflow sign | 0 | 0 | 0 | 0 | 0 | 0 |
Outlier filtering example two:
| collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Time interval rainfall | P＝1.0 | P＝40.0 | P＝0 | P＝0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 4.1 | 0.1 | 0.2 | 0.4 | 0.5 |
| Overflow sign | 0 | 1 | 0 | 0 | 0 | 0 |
It can be seen that at 16 points, data are abnormal, and in the case of a rainfall of 5.0, it is impossible to obtain a unit evaporation amount of EI4.1-0.2-3.9, so that the time period of change is judged to be abnormal, 0 is assigned to the evaporation capacity of the time period of change, and the actual evaporation capacity is changed according to the overflow capacity mark and the actually stored evaporation capacity in sequence.
The above table was changed to the table below, and the daily evaporation was 0.2+ 0.5-0.7
| Collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00(The next day) |
| Time interval rainfall | P＝1.0 | P＝40.0 | P＝0 | P＝0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 0.2 | 0.1 | 0.2 | 0.4 | 0.5 |
| Overflow sign | 0 | 1 | 0 | 0 | 0 | 0 |
Outlier filtering example three:
| collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Time interval rainfall | P＝1.0 | P＝5.0 | P＝0 | P＝0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 4.1 | 0.7 | 0.8 | 0.9 | 1.0 |
| Overflow sign | 0 | 0 | 0 | 0 | 0 | 0 |
It can be seen that at 16 points, data are abnormal, and in the case of a rainfall of 5.0, it is impossible to obtain a unit evaporation amount of EIThe time interval is judged to be different from 4.1 to 0.2 to 3.9And (4) always assigning 0 to the evaporation capacity in the time period, and then changing the actual evaporation capacity according to the overflow capacity mark and the actually stored evaporation capacity in sequence.
The above table was modified as follows, and the daily evaporation amount was 1.0
| Collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Time interval rainfall | P＝1.0 | P＝5.0 | P＝0 | P＝0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 0.2 | 0.7 | 0.8 | 0.9 | 1.0 |
| Overflow sign | 0 | 0 | 0 | 0 | 0 | 0 |
Outlier filtering example four:
| collection point | 12:00 | 16:00 | 20:00 | 00:00 (the next day) | 4:00 (the next day) | 8:00 (the next day) |
| Time interval rainfall | P＝1.0 | P＝40.0 | P＝0 | P＝20.0 | P＝0 | P＝0 |
| Amount of evaporation | 0.2 | 4.1 | 0.1 | 3.1 | 3.2 | 3.4 |
| Overflow sign | 0 | 1 | 0 | 0 | 0 | 0 |
It can be seen that at 16 points, data are abnormal, and in the case of a rainfall of 5.0, it is impossible to obtain a unit evaporation amount of EI4.1-0.2-3.9, therefore, the time period is judged to be abnormal, 0 is assigned to the evaporation amount of the time period, and the actual evaporation amount is changed according to the overflow amount mark and the actually stored evaporation amount in sequence. And at the point 0, the data is abnormal, the rainfall is 20, and the unit evaporation amount E2 is not possible to be 3.1-0.1-3, so that the time period is judged to be abnormal, 0 is assigned to the evaporation amount of the time period, and the actual evaporation amount is changed according to the overflow amount mark and the actually stored evaporation amount in sequence.
The above table is modified as follows, and the daily evaporation is 0.2+ 0.4-0.6
In the calculation process, the time interval evaporation of each monitoring time interval is calculated according to the data in the table, and according to the rainfall data of each time interval, if the evaporation data of a certain monitoring time interval exceeds the maximum value of normal non-rainfall, the data is abnormal, and the data filtering is needed. And sequentially filtering all the accumulation periods of the following evaporation monitoring period on the current day.
In addition, a warning line can be arranged above the overflow line, when rainfall enables the water level of the evaporation barrel to reach the warning line, the liquid level monitoring is stopped, the evaporation amount in the period is zero, the monitoring is carried out again after the overflow is carried out until the next collection point, and the evaporation amount is the accumulated value before the overflow and the stage value (or the accumulated value) after the overflow.
As an improvement, the time of water replenishing and overflowing can be automatically controlled within a certain range, the water replenishing or overflowing time required by unit height is set by adding a manual setting mode, the height difference is calculated by measuring the liquid level, the specific time required by water replenishing and overflowing is automatically calculated by the device based on the water replenishing and overflowing speed of the device, so that the opening and closing time of the valve is controlled, and the reference liquid level is controlled. It should be noted that the refill and overflow times should be controlled to be within time unit T2, which is 15 minutes in this example. After water supplement or overflow is completed, the device collects the liquid level after waiting for the liquid level balance, and records the liquid level as a reference liquid level.
The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and such improvements and modifications are also considered to be within the scope of the present invention.
Claims (8)
1. A high-precision water surface evaporation capacity monitoring method is characterized by comprising the following steps:
step one, dividing each day into a plurality of monitoring time intervals, taking the starting time point of each monitoring time interval as an acquisition point, and dividing each monitoring time interval into a plurality of small time units;
step two, collecting the water level in the evaporation device at a first collection point, actively overflowing to the outside of the evaporation device when the water level is higher than an overflow line, and actively replenishing water to the inside of the evaporation device when the water level is lower than a water replenishing line;
when the liquid level of the first collection point exceeds an overflow line or is lower than a water replenishing line, overflowing or water replenishing occurs, judging whether rainfall exists in each time unit or not after the first collection point and the time unit, and when the rainfall does not exist, taking the reference rainfall as the rainfall before the time unit; if the rainfall exists, continuously judging the rainfall condition of the next time unit until no rainfall is judged, wherein the reference rainfall is the rainfall before the time unit, and the reference water level is the rear water level of the first time unit without rainfall after water replenishing and overflowing;
when the liquid level of the first collection point is not more than the overflow line and not less than the water replenishing line, whether rainfall exists in the previous time unit is judged: if no rainfall exists, taking the rainfall before the time unit according to the reference rainfall, and taking the water level after the time unit according to the reference water level;
if the rainfall exists, judging whether the rainfall exists in the next time unit or not after the first acquisition point, if the rainfall does not exist, calculating the reference rainfall as the rainfall before the time unit, and taking the reference water level as the rear water level of the first time unit without the rainfall after the first acquisition point;
collecting water levels in the evaporation device at other collection points, and when the liquid level of the collection point exceeds an overflow line, overflowing occurs: judging whether rainfall exists in each time unit after the collection point and the time unit, and taking the reference rainfall as the rainfall before the time unit when the rainfall does not exist; if the rainfall exists, continuously judging the rainfall condition of the next time unit until no rainfall is judged, wherein the reference rainfall is the rainfall before the time unit, and the reference water level is the rear water level of the first time unit without rainfall after the water replenishing overflow is finished;
if no overflow occurs, directly using the previously set reference rainfall and reference water level, and continuing to the next collection point to execute the step three;
step four, collecting water level at the end time point of each monitoring period as calculated water level, and taking rainfall before the last time unit of each monitoring period as calculated rainfall;
step five, calculating the evaporation capacity of each monitoring period according to the following formula at the end time point of each monitoring period and transmitting the data to a data center:
E＝P+(h1-h2)
h1 is the water level calculated in the fourth step, h2 is the reference water level in the third step, and P is the calculated rainfall-reference rainfall;
and step six, accumulating the evaporation capacity at the collection point where the overflow occurs every time in the day to obtain the total evaporation capacity in the day.
2. The high-precision water surface evaporation amount monitoring method according to claim 1, wherein the method comprises the following steps: and in the fifth step, when the liquid level of the collection point exceeds an overflow line or is lower than a water replenishing line, after water replenishing or overflow occurs, calculating the evaporation capacity in the period, judging whether rainfall exists in a time interval from the collection point to the collection point by adding compensation, if no rainfall exists, calculating the evaporation capacity in the period, namely 8/7, performing evaporation compensation, and if rainfall exists, not performing evaporation compensation.
3. The high-precision water surface evaporation amount monitoring method according to claim 2, wherein: the compensation judgment time is 2 time units.
4. The high-precision water surface evaporation amount monitoring method according to claim 1, wherein the method comprises the following steps: and filtering abnormal values, if the rainfall period exists in the monitoring period and the rainfall is too large and the evaporation amount is too large, filtering data, and removing the abnormal accumulated value aiming at the evaporation amount data of the collection point before the next overflow collection point.
5. The high-precision water surface evaporation amount monitoring method according to claim 1, wherein the method comprises the following steps: when the evaporation data in a certain monitoring period exceeds the maximum value of normal rainfall, the data is abnormal, data filtering is needed, and an abnormal accumulated value is eliminated aiming at the evaporation data of the collection point before the next overflow collection point.
6. The high-precision water surface evaporation amount monitoring method according to claim 1, wherein the method comprises the following steps: when rainfall makes the evaporation bucket water level reach the warning line, stop the liquid level monitoring, this period evaporation capacity is zero, monitors again after overflowing until next acquisition point.
7. The high-precision water surface evaporation amount monitoring method according to claim 1, wherein the method comprises the following steps: also comprises the following steps:
the water replenishing or overflowing time required by the unit height is preset, the height difference is calculated by measuring the liquid level when water is required to be replenished or overflowing, and the specific time required by water replenishing and overflowing is calculated, so that the opening and closing time of the valve is controlled, and the reference liquid level in the evaporation barrel is accurately controlled.
8. The high-precision water surface evaporation amount monitoring method according to claim 1, wherein the method comprises the following steps: the monitoring time period is 4 hours, the time unit is 15 minutes, the active overflow time is 15 minutes, and the compensation judgment time is 30 minutes.
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| US6401530B1 (en) * | 1999-02-23 | 2002-06-11 | Claber S.P.A. | Rain sensor |
| KR20120009794A (en) * | 2010-07-21 | 2012-02-02 | 부경대학교 산학협력단 | Apparatus and method of measuring natural evaporating, icing, melting |
| CN206223753U (en) * | 2016-06-15 | 2017-06-06 | 江苏南水水务科技有限公司 | A kind of water surface evaporation automated watch-keeping facility |
| CN107037503A (en) * | 2016-12-23 | 2017-08-11 | 北京美科华仪科技有限公司 | A kind of evaporation from water surface measurement apparatus and system |
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| US6401530B1 (en) * | 1999-02-23 | 2002-06-11 | Claber S.P.A. | Rain sensor |
| KR20120009794A (en) * | 2010-07-21 | 2012-02-02 | 부경대학교 산학협력단 | Apparatus and method of measuring natural evaporating, icing, melting |
| CN206223753U (en) * | 2016-06-15 | 2017-06-06 | 江苏南水水务科技有限公司 | A kind of water surface evaporation automated watch-keeping facility |
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