Some standard content:
ICS07.060
National Standard of the People's Republic of China
GB/T336942017
Specification Observing for automatic climatological station Issued on 2017-05-12
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implementation on 2017-12-01
GB/T33694—2017
1 Scope
Normative references
Terms and definitions
Basic requirements
Observation items
Time system and day boundary
Observation tasks
Observation site
Metadata
Observation methods
Measurement performance requirements
Instrument layout and installation
Maintenance and verification
Sampling and algorithm
Data quality control
6 Data files
Basic information of the site
6.3 Element observation values
6.4 Quality control information
Appendix A (Normative Appendix)
Appendix B (Normative Appendix)
References
Sampling and algorithm
Data quality control method
This standard was drafted in accordance with the rules given in GB/T1.1-2009. This standard was proposed by the China Meteorological Administration.
This standard is under the jurisdiction of the National Technical Committee for Standardization of Meteorological Instruments and Observation Methods (SAC/TC507). GB/T33694—2017
Drafting units of this standard: Meteorological Observation Center of China Meteorological Administration, Henan Meteorological Bureau, Hebei Meteorological Bureau, Beijing Meteorological Bureau, Shandong Meteorological Bureau, Jiangsu Radio Science Research Institute Co., Ltd. Main drafters of this standard: Wang Bolin, Zhang Xin, Zhang Fan, Cao Tie, Liu Wenzhong, Wu Yongxue, Song Shuli, Hua Weidong, Chen Dongdong, Yao LuntaoH
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1 Scope
Observation specification for automatic climate station
This standard specifies the basic requirements and observation methods for automatic climate station observation. This standard applies to ground climate observations by automatic climate stations. 2 Normative references
GB/T336942017
The following documents are indispensable for the application of this document. For all dated references, only the dated versions apply to this document. For any undated referenced document, the latest version (including all amendments) shall apply to this document. GB31221-2014 Meteorological Detection Environmental Protection Specification Ground Meteorological Observation Station QX4-2015 Meteorological Station (Station) Lightning Protection Technical Specification QX/T45-2007 Ground Meteorological Observation Specification QX/T118-2010 Ground Meteorological Observation Data Quality Control 3 Terms and Definitions
The terms and definitions defined in QX/T45-2007 and the following terms and definitions apply to this document. For ease of use, some terms and definitions in QX/T45-2007 are repeated below. 3.1
Climate
indicates the long-term average state of the physical characteristics of the atmosphere in a certain area on the earth, and is a comprehensive expression of various weather processes during that period. Note: The statistics of meteorological elements such as temperature, precipitation and radiation are the basic basis for describing climate. 3.2
automatic climatological stationAutomatic climatological station
High-precision, high-stability automatic observation instrument used for ground-based climate observation. 3.3
Metadata
is "data about data". That is, data about the content, quality, conditions and other characteristics of data. Its basic function is to describe the data.
[QX/T45—2007 definition 3.22]
4 Basic requirements
4.1 Observation items
should include the following observation elements:
- Temperature:
- Precipitation.
It is advisable to add but not limited to the following observation elements: 1
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GB/T33694—2017
Air pressure;
-Air humidity:
-Wind direction;
Wind speed;
Ground temperature:
Total radiation.
4.2 Time system and day boundary
Observation items generally adopt Beijing time, and it is advisable to take Beijing time 20 o'clock as the day boundary. Total radiation observation adopts local mean solar time, and takes local mean solar time 24 o'clock as the day boundary.
4.3 Time calibration
It has automatic time calibration function, and is based on Beijing time, with an error of no more than 30s. 4.4 Observation tasks
Continuous observation should be carried out for 24 hours every day.
4.5 Observation site
Should meet the following requirements:
The location should reflect the climate characteristics of a larger local area; maintain the natural underlying surface:
-The detection environment should comply with Chapter 3 of GB31221-2014;-Establish obvious signs and set up fences on the site; measure the longitude and latitude and altitude of the center of the observation site; set up meteorological detection environment protection warning signs at the observation site: Set up lightning protection facilities in accordance with the requirements of QX4-2015. 4.6 Metadata
A meteorological observation metadata archive containing the following contents should be established, and change information should be recorded: 1. Observation station: station name, observation mode, district station number, geographical location; Geographical environment: surface cover, terrain characteristics, observation data affected by external factors due to instrument installation orientation, surrounding environment of the observation field and its impact on observation data;
Observation elements: element value name, measurement unit, observation time: data collection and analysis methods;
Data quality information:
Observation instrument information: instrument measurement range, sensor height above the ground, instrument calibration time, last calibration date, time and validity period, instrument model and serial number, instrument regular maintenance status, instrument use date and time. 5 Observation method
5.1 Measurement performance requirements
Automatic climate stations should include sensors, collectors, power supply units, structures and installation accessories, etc. Sensor configuration and measurement performance should meet the requirements of Tables 1 and 2.
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Meteorological elements
Precipitation
Air humidity
Ground temperature
Total radiation
Meteorological elements
Precipitation
Relative humidity
Ground temperature
Total radiation
Sensor name
Sensor configuration table
Platinum resistance temperature sensor
Tipping bucket rainfall sensor
Weighing precipitation sensor
Air pressure sensor
Humidity sensor
Wind direction sensor
Wind speed sensor||tt| |Infrared temperature sensor
Total radiation sensor
Measuring range
-50℃~+50℃
Tipping bucket: greater than 0.1mm
Weighing: 0mm~400mm
Basic type: 500hPa1100hPa
Highland type: 450hPa~900hPa
5%~100%
0°~360°
0m/s~60m/s
-50℃~80℃
0W/m~2000W/m
V is the actual wind speed.
Instrument layout and installation
The layout meets the following requirements:
Technical performance requirements
Resolution
GB/T33694—2017
Required.
The difference between the measured values should be ≤0.1℃, and the deviation size and change direction within the measurement range are consistent.
Maximum allowable error
±0.4mm(≤10mm)
±4%(>10 mm)
±0.4mm(≤10mm)
±4%(>10mm)
±2%≤80%）)
±3%(>80%)
±(0.5m/s+0.03V)*
Uncertainty:
8% (hourly twilight radiation)
5% (sunny twilight radiation)
High instruments and facilities should be installed on the north side of the observation site, and low instruments and facilities should be installed on the south side of the observation site; instruments and facilities should be arranged in rows from east to west and in columns from north to south; adjacent instruments should not block or affect each other: 3
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The total radiation sensor should be installed on the south side of the observation site, and the sensing surface should not be blocked by any obstacles. The installation should meet the requirements of Table 3.
Table 3 Sensor installation requirements
Air temperature sensor
Humidity sensor
Wind direction sensor
Wind speed sensor
Air pressure sensor
Tipping bucket rainfall sensor
Weighing precipitation sensor
Infrared ground temperature sensor
Global radiation sensor
Maintenance and calibration
Should be carried out in accordance with the following requirements:
Requirements and error range
Height 150cm
Height 150cm
Height 150cm and 1000cm
North orientation
Height 150cm and 1000cm
Installed in the collector chassis
±10cm| |tt||Benchmark part
Top end of sensing part
Center of sensing part
Center of wind vane
Azimuth north mark (needle)
±10cm
Height not less than 70cm, not higher than 300cm
Height 120cm
Windbreak ring should be installed
Height 150cm
Bracket height 150cm
Maintain the observation site and instruments regularly and record them in time; when any instrument is found to be faulty, it should be repaired or replaced in time±3cm
±10cm
±10cm
When the measured values of the temperature sensors differ by more than 0.2C, the cause should be found out in time: use instruments that have passed the verification or calibration.
5.4 Sampling and algorithm
5.4.1 Sampling
The sampling frequency shall comply with the requirements of Table 4.
2 Algorithm
Instantaneous value time interval
The instantaneous value time interval of each meteorological variable shall comply with the requirements of Table 4. Instantaneous value calculation
The calculation of instantaneous value shall comply with the requirements of Table 4. The calculation method is shown in Appendix A. 4
Center of wind cup
Center position of sensor
Infrared transmitter
North-south line of bracket mounting surface base
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Meteorological variables
Relative humidity
Ground temperature
Precipitation
(Tipping bucket observation method)
Precipitation
(Weighing observation method)
Total radiation
(Irradiance)
Total radiation
(Radiation)
Sampling frequency
30 times/min
30 times/min
30 times/min||tt ||4 times/s
1 time/s
30 times/min
1 time/min
1 time/min
30 times/min
5.4.2.3 Calculation of temperature timing value
Table 4 Calculation method of instantaneous meteorological value
Time interval
3s average value: 3s
1min average value: 1min
2min average value: 2min
10min average value: 10min
1min average value: 1min
2min average value: 2min
10min average value: 10m in
Indication update
GB/T33694—2017
Calculation method
30 samples, arithmetic average method, see A.1.1150 samples, sliding average method, see A.1.230 samples, arithmetic average method, see A.1.130 samples, arithmetic average method, see A.1.112 samples, sliding average method, see A.1.2Taking the 3s average value at the whole second as the sample, 60 samples, arithmetic average method, see A.1.1
Taking the 3s average value at the whole second as the sample, 120 samples, arithmetic average method, see A.1.1
Taking the 1min average value as the sample, 10 samples, sliding average method, see A.1.2bzxZ.net
60 samples, unit loss average method, see A.1.3120 samples, unit loss average method, see A.1.3Take 1min average value as sample, 10 samples, unit loss sliding average method, see A.1.4
30 samples, arithmetic mean method, see A.1.1Arithmetic sum method, see A4.1
Calculate the difference between the total precipitation sampling values of 2min, see A.4.1
Arithmetic mean method, see A.1.1
Derived from the instantaneous irradiance value, see A.4.2
The temperature timing value should be calculated according to the temperature timing value algorithm in A.3 to obtain the temperature timing value of each of the three temperature sensors. 5.5 Data quality control
Data quality control should be carried out on the sampling values and instantaneous values of each meteorological variable according to the method given in Appendix B, and the data should be marked according to the results of data quality control.
6 Data file
6.1 Overview
The data file should contain the following contents:
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GB/T33694—2017
一Basic information of the station;
一Element observation value;
一Quality control information.
Basic information of the station
Should at least include the following contents:
一Measuring station name and code:
Observation site latitude:
Observation site longitude:
Observation site altitude;
Observation method.
Element observation value
should include the following contents:
Observation time;
Minute observation data of each element:
Hourly observation data of each element:
-Extreme value of each element and the time when the extreme value occurs. Quality control information
should include the following identification contents of observation data: correct;
suspicious;
error;
-missing;
modified;
-other situations.
A.1 Average value calculation formula
A.1.1 Arithmetic mean method
Should be calculated according to formula (A.1):
Where:
—average value of meteorological variables during the observation period; y
Appendix A
(Normative Appendix)
Sampling and algorithm
GB/T33694—2017
The ith sampling instantaneous value (sample) of the meteorological variable during the observation period, where: "errors" and "suspicious" samples that are not "correct" should be discarded and not used for calculation, that is, let y: = 0; N——the total number of samples during the observation period;
Observation The number of "correct" samples in the measurement period (m≤N). Note: When m=N and N≤10, the truncated average method can be used to calculate. After removing the maximum and minimum values of a set of data, the average value of the remaining values is calculated to make the average value have a strong concentration trend. A.1.2
The sliding average method
should be calculated according to formula (A.2):
wherein:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" and "suspicious" samples that are not "correct" should be discarded and not used for calculation; a
the first sample in the moving average time interval; when n2) Calculation:
Where:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" "suspicious" and other non-"correct" samples should be discarded and not used for calculation; a
- the first sample in the moving average time interval; when n2) Calculation:
Where:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" "suspicious" and other non-"correct" samples should be discarded and not used for calculation; a
- the first sample in the moving average time interval; when n2C: The cause should be found out in time: Use qualified instruments for verification or calibration.
5.4 Sampling and algorithm
5.4.1 Sampling
The sampling frequency should meet the requirements of Table 4.
2 Algorithm
Instantaneous value time interval
The instantaneous value time interval of each meteorological variable should meet the requirements of Table 4. Instantaneous value calculation
The calculation of instantaneous value should meet the requirements of Table 4. The calculation method is shown in Appendix A. 4
Center of wind cup
Center position of sensor
Infrared transmitter
North-south line of bracket mounting surface base
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Meteorological variables
Relative humidity
Ground temperature
Precipitation
(Tipping bucket observation method)
Precipitation
(Weighing observation method)
Total radiation
(Irradiance)
Total radiation
(Radiation)
Sampling frequency
30 times/min
30 times/min
30 times/min||tt ||4 times/s
1 time/s
30 times/min
1 time/min
1 time/min
30 times/min
5.4.2.3 Calculation of temperature timing value
Table 4 Calculation method of instantaneous meteorological value
Time interval
3s average value: 3s
1min average value: 1min
2min average value: 2min
10min average value: 10min
1min average value: 1min
2min average value: 2min
10min average value: 10m in
Indication update
GB/T33694—2017
Calculation method
30 samples, arithmetic average method, see A.1.1150 samples, sliding average method, see A.1.230 samples, arithmetic average method, see A.1.130 samples, arithmetic average method, see A.1.112 samples, sliding average method, see A.1.2Taking the 3s average value at the whole second as the sample, 60 samples, arithmetic average method, see A.1.1
Taking the 3s average value at the whole second as the sample, 120 samples, arithmetic average method, see A.1.1
Taking the 1min average value as the sample, 10 samples, sliding average method, see A.1.2
60 samples, unit loss average method, see A.1.3120 samples, unit loss average method, see A.1.3Take 1min average value as sample, 10 samples, unit loss sliding average method, see A.1.4
30 samples, arithmetic mean method, see A.1.1Arithmetic sum method, see A4.1
Calculate the difference between the total precipitation sampling values of 2min, see A.4.1
Arithmetic mean method, see A.1.1
Derived from the instantaneous irradiance value, see A.4.2
The temperature timing value should be calculated according to the temperature timing value algorithm in A.3 to obtain the temperature timing value of each of the three temperature sensors. 5.5 Data quality control
Data quality control should be carried out on the sampling values and instantaneous values of each meteorological variable according to the method given in Appendix B, and the data should be marked according to the results of data quality control.
6 Data file
6.1 Overview
The data file should contain the following contents:
HiiKAoNi KAca
GB/T33694—2017
一Basic information of the station;
一Element observation value;
一Quality control information.
Basic information of the station
Should at least include the following contents:
一Measuring station name and code:
Observation site latitude:
Observation site longitude:
Observation site altitude;
Observation method.
Element observation value
should include the following contents:
Observation time;
Minute observation data of each element:
Hourly observation data of each element:
-Extreme value of each element and the time when the extreme value occurs. Quality control information
should include the following identification contents of observation data: correct;
suspicious;
error;
-missing;
modified;
-other situations.
A.1 Average value calculation formula
A.1.1 Arithmetic mean method
Should be calculated according to formula (A.1):
Where:
—average value of meteorological variables during the observation period; y
Appendix A
(Normative Appendix)
Sampling and algorithm
GB/T33694—2017
The ith sampling instantaneous value (sample) of the meteorological variable during the observation period, where: "errors" and "suspicious" samples that are not "correct" should be discarded and not used for calculation, that is, let y: = 0; N——the total number of samples during the observation period;
Observation The number of "correct" samples in the measurement period (m≤N). Note: When m=N and N≤10, the truncated average method can be used to calculate. After removing the maximum and minimum values of a set of data, the average value of the remaining values is calculated to make the average value have a strong concentration trend. A.1.2
The sliding average method
should be calculated according to formula (A.2):
wherein:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" and "suspicious" samples that are not "correct" should be discarded and not used for calculation; a
the first sample in the moving average time interval; when n2C: The cause should be found out in time: Use qualified instruments for verification or calibration.
5.4 Sampling and algorithm
5.4.1 Sampling
The sampling frequency should meet the requirements of Table 4.
2 Algorithm
Instantaneous value time interval
The instantaneous value time interval of each meteorological variable should meet the requirements of Table 4. Instantaneous value calculation
The calculation of instantaneous value should meet the requirements of Table 4. The calculation method is shown in Appendix A. 4
Center of wind cup
Center position of sensor
Infrared transmitter
North-south line of bracket mounting surface base
HiiKAoNiKAca
Meteorological variables
Relative humidity
Ground temperature
Precipitation
(Tipping bucket observation method)
Precipitation
(Weighing observation method)
Total radiation
(Irradiance)
Total radiation
(Radiation)
Sampling frequency
30 times/min
30 times/min
30 times/min||tt ||4 times/s
1 time/s
30 times/min
1 time/min
1 time/min
30 times/min
5.4.2.3 Calculation of temperature timing value
Table 4 Calculation method of instantaneous meteorological value
Time interval
3s average value: 3s
1min average value: 1min
2min average value: 2min
10min average value: 10min
1min average value: 1min
2min average value: 2min
10min average value: 10m in
Indication update
GB/T33694—2017
Calculation method
30 samples, arithmetic average method, see A.1.1150 samples, sliding average method, see A.1.230 samples, arithmetic average method, see A.1.130 samples, arithmetic average method, see A.1.112 samples, sliding average method, see A.1.2Taking the 3s average value at the whole second as the sample, 60 samples, arithmetic average method, see A.1.1
Taking the 3s average value at the whole second as the sample, 120 samples, arithmetic average method, see A.1.1
Taking the 1min average value as the sample, 10 samples, sliding average method, see A.1.2
60 samples, unit loss average method, see A.1.3120 samples, unit loss average method, see A.1.3Take 1min average value as sample, 10 samples, unit loss sliding average method, see A.1.4
30 samples, arithmetic mean method, see A.1.1Arithmetic sum method, see A4.1
Calculate the difference between the total precipitation sampling values of 2min, see A.4.1
Arithmetic mean method, see A.1.1
Derived from the instantaneous irradiance value, see A.4.2
The temperature timing value should be calculated according to the temperature timing value algorithm in A.3 to obtain the temperature timing value of each of the three temperature sensors. 5.5 Data quality control
Data quality control should be carried out on the sampling values and instantaneous values of each meteorological variable according to the method given in Appendix B, and the data should be marked according to the results of data quality control.
6 Data file
6.1 Overview
The data file should contain the following contents:
HiiKAoNi KAca
GB/T33694—2017
一Basic information of the station;
一Element observation value;
一Quality control information.
Basic information of the station
Should at least include the following contents:
一Measuring station name and code:
Observation site latitude:
Observation site longitude:
Observation site altitude;
Observation method.
Element observation value
should include the following contents:
Observation time;
Minute observation data of each element:
Hourly observation data of each element:
-Extreme value of each element and the time when the extreme value occurs. Quality control information
should include the following identification contents of observation data: correct;
suspicious;
error;
-missing;
modified;
-other situations.
A.1 Average value calculation formula
A.1.1 Arithmetic mean method
Should be calculated according to formula (A.1):
Where:
—average value of meteorological variables during the observation period; y
Appendix A
(Normative Appendix)
Sampling and algorithm
GB/T33694—2017
The ith sampling instantaneous value (sample) of the meteorological variable during the observation period, where: "errors" and "suspicious" samples that are not "correct" should be discarded and not used for calculation, that is, let y: = 0; N——the total number of samples during the observation period;
Observation The number of "correct" samples in the measurement period (m≤N). Note: When m=N and N≤10, the truncated average method can be used to calculate. After removing the maximum and minimum values of a set of data, the average value of the remaining values is calculated to make the average value have a strong concentration trend. A.1.2
The sliding average method
should be calculated according to formula (A.2):
wherein:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" and "suspicious" samples that are not "correct" should be discarded and not used for calculation; a
the first sample in the moving average time interval; when n1
Calculate the difference between the total precipitation sampling values of 2 minutes, see A.4.1
Arithmetic mean method, see A.1.1
Derived from the instantaneous irradiance value, see A.4.2
The temperature timing value algorithm of A.3 should be used to calculate the temperature instantaneous value of each of the three temperature sensors to obtain the temperature timing value. 5.5 Data quality control
Data quality control should be performed on the sampling values and instantaneous values of each meteorological variable according to the method given in Appendix B, and the data should be marked according to the results of data quality control.
6 Data file
6.1 Overview
The data file should contain the following contents:
HiiKAoNi KAca
GB/T33694—2017
-Basic information of the station;
-Element observation value;
-Quality control information.
Basic information of the station
should at least include the following contents:
- Station name and code:
Latitude of the observation site:
Longitude of the observation site:
Altitude of the observation site above sea level;
Observation method.
Element observation value
should include the following contents:
Observation time;
Minute observation data of each element:
Hourly observation data of each element:
-Extreme value of each element and the time when the extreme value occurs. Quality control information
should include the following identification contents of the observation data: correct;
suspicious;
error;
-missing;
modified;
-other situations.
A.1 Average value calculation formula
A.1.1 Arithmetic mean method
Should be calculated according to formula (A.1):
Where:
—average value of meteorological variables during the observation period; y
Appendix A
(Normative Appendix)
Sampling and algorithm
GB/T33694—2017
The ith sampling instantaneous value (sample) of the meteorological variable during the observation period, where: "errors" and "suspicious" samples that are not "correct" should be discarded and not used for calculation, that is, let y: = 0; N——the total number of samples during the observation period;
Observation The number of "correct" samples in the measurement period (m≤N). Note: When m=N and N≤10, the truncated average method can be used to calculate. After removing the maximum and minimum values of a set of data, the average value of the remaining values is calculated to make the average value have a strong concentration trend. A.1.2
The sliding average method
should be calculated according to formula (A.2):
wherein:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" and "suspicious" samples that are not "correct" should be discarded and not used for calculation; a
the first sample in the moving average time interval; when n1
Calculate the difference between the total precipitation sampling values of 2 minutes, see A.4.1
Arithmetic mean method, see A.1.1
Derived from the instantaneous irradiance value, see A.4.2
The temperature timing value algorithm of A.3 should be used to calculate the temperature instantaneous value of each of the three temperature sensors to obtain the temperature timing value. 5.5 Data quality control
Data quality control should be performed on the sampling values and instantaneous values of each meteorological variable according to the method given in Appendix B, and the data should be marked according to the results of data quality control.
6 Data file
6.1 Overview
The data file should contain the following contents:
HiiKAoNi KAca
GB/T33694—2017
-Basic information of the station;
-Element observation value;
-Quality control information.
Basic information of the station
should at least include the following contents:
- Station name and code:
Latitude of the observation site:
Longitude of the observation site:
Altitude of the observation site above sea level;
Observation method.
Element observation value
should include the following contents:
Observation time;
Minute observation data of each element:
Hourly observation data of each element:
-Extreme value of each element and the time when the extreme value occurs. Quality control information
should include the following identification contents of the observation data: correct;
suspicious;
error;
-missing;
modified;
-other situations.
A.1 Average value calculation formula
A.1.1 Arithmetic mean method
Should be calculated according to formula (A.1):
Where:
—average value of meteorological variables during the observation period; y
Appendix A
(Normative Appendix)
Sampling and algorithm
GB/T33694—2017
The ith sampling instantaneous value (sample) of the meteorological variable during the observation period, where: "errors" and "suspicious" samples that are not "correct" should be discarded and not used for calculation, that is, let y: = 0; N——the total number of samples during the observation period;
Observation The number of "correct" samples in the measurement period (m≤N). Note: When m=N and N≤10, the truncated average method can be used to calculate. After removing the maximum and minimum values of a set of data, the average value of the remaining values is calculated to make the average value have a strong concentration trend. A.1.2
The sliding average method
should be calculated according to formula (A.2):
wherein:
Y, the average value of the meteorological variable calculated for the nth time; y: - the i-th sample value. Among them: "wrong" and "suspicious" samples that are not "correct" should be discarded and not used for calculation; a
the first sample in the moving average time interval; when nWhen N is a=nN+1
N is the total number of samples in the average time interval; the number of correct data samples in the moving average time interval (mN). The unit vector average method
should be calculated according to formula (A.3):
W,=arctan
Where:
The average wind direction in an observation period;
The amplitude angle of the wind loss in an observation period (the angle with the y-axis):.(A.2)
GB/T33694—2017
The average component of the unit vector on the y-axis (west-east direction) in an observation period: x
xZsinD
-The average component of the unit vector on the y-axis (north-south direction) in the observation period: Y
The total number of samples in an observation period.
According to the positive and negative of x and Y, W is adjusted according to the following method. Correction: x>0.Y>0.W. No correction required:
x>0.Y<0 or x
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