A method for issuing regional wind shear warning based on lidar

Abstract

A method for issuing regional wind shear warnings based on laser radar. It includes using laser radar to obtain the original radial echo wind speed data of the entire scanning area at different times; applying the fitting window idea based on the neighborhood frequency method to remove noise and fill in missing values; using the regional growing method to identify wind shear, and outputting the wind shear intensity and wind shear position distribution corresponding to different times; dividing multiple regions and issuing wind shear warnings based on the wind shear information in a time-space angle combined with the wind shear intensity. The present invention solves the problem of frequent warnings in existing warnings by issuing wind shear warnings based on the wind shear intensity combined with the time-space angle, reduces the difference between the number of wind shear warnings provided by the laser radar and the number of wind shears actually encountered by the aircraft, reduces the false alarm rate, and improves the accuracy of the results of warning issuance. Finally, a complete wind shear warning system of reasonable warnings, reasonable correction of warnings, and reasonable cancellation of warnings is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of wind laser radar application, and specifically relates to a method for issuing regional wind shear warning based on laser radar. Background Art

[0002] Wind shear is an internationally recognized atmospheric phenomenon that seriously affects flight safety. Many major air crashes are caused by low-altitude wind shear. Encountering wind shear will cause the aircraft speed to change instantly, which in turn causes the aircraft lift to change, and finally causes the flight path to deviate from the course and cause an accident. Since wind shear is characterized by small scale, short duration, high intensity, and difficulty in warning, it has a great impact on the aircraft during departure and arrival. Therefore, efficient detection and timely warning of wind shear are very important.

[0003] At present, with the improvement of lidar hardware performance and identification methods, the basic detection capability and timely warning of radar have made great progress. The existing warning release method is to judge the wind shear level in each area on the runway and glide path based on the wind shear intensity and the wind shear intensity standard promulgated by the International Civil Aviation Organization ICAO, and finally determine the area where the warning is issued and the corresponding warning information of the area. However, in the actual warning business, there is a significant difference between the number of wind shear warnings provided by the lidar wind measurement data and the number of verifications of the aircraft encountering wind shear events. This is because the existing warning release method only considers the changes in wind shear wind speed intensity, and does not release wind shear warnings from the perspective of wind shear wind speed intensity combined with time and space. When there is a slight weather condition, continuous and uninterrupted warnings will be issued, making the final warning release result low in accuracy, and frequent warnings have an adverse effect on flight safety. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a method for issuing regional wind shear warnings based on laser radar.

[0005] In order to achieve the above object, the method for issuing regional wind shear warning based on laser radar provided by the present invention comprises the following steps performed in sequence:

[0006] 1) Set the laser radar's location, scanning mode, scanning angle, and scanning area, use the laser radar to scan the scanning area, and obtain the original radial echo wind speed data of each radar echo point at different times in the entire scanning area;

[0007] 2) For the above original radial echo wind speed data, the fitting window idea is applied on the basis of the neighborhood frequency method to remove noise and fill in missing values ​​to obtain effective radial wind speed data;

[0008] 3) Using the above radial wind speed valid data, the regional growing method is used to identify wind shear, and the wind shear intensity and wind shear position distribution corresponding to different times are output;

[0009] 4) Divide into multiple areas and issue wind shear warnings based on the above wind shear information in a temporal and spatial perspective combined with the wind shear intensity.

[0010] In step 1), the specific method of setting the laser radar's setting position, scanning mode, scanning angle and scanning area is:

[0011] The laser radar is deployed at a position more than 200m vertically away from the center line of the airport runway; the laser radar adopts the glide path scanning method; the glide path scanning angle adopts the same elevation angle as the glide path slope. When the aircraft lands and approaches the airport, the glide path slope is 3 degrees, and the scanning angle adopts an elevation angle of 3 degrees. When the aircraft takes off and leaves the airport, the glide path slope is 6 degrees, and the scanning angle adopts an elevation angle of 6°. The scanning area is the aircraft glide path and the air above the airport runway.

[0012] In step 2), the specific method of removing noise and filling missing values ​​by applying the fitting window idea to the above original radial echo wind speed data based on the neighborhood frequency method to obtain valid radial wind speed data is as follows:

[0013] 2.1) Divide the original radial echo wind speed data in the window M*N into n equally spaced intervals, with the interval interval set to Δd and the original value of the window center point set to v ij ;

[0014] 2.2) The frequency of radar echo points in different intervals within the statistical window M*N (x1, x2...x n ) and the original radial echo wind speed data x′ corresponding to the radar echo point, and let x m is the frequency (x1,x2...x n ) and the maximum value of the original radial echo wind speed data x′, v n The maximum value x m The middle value of the corresponding interval; v' ij is the new value of the window center point, the formula is as follows:

[0015]

[0016] In the formula, k1 is the noise removal threshold, k2 is the missing value threshold;

[0017] 2.3) According to the above formula, noise is removed and missing values ​​are filled, and the original radial echo wind speed data x′ of all radar echo points in the window M*N or the maximum value x in the interval is mCompare with the noise removal threshold k1 or the missing value threshold k2 to determine whether it is a valid radar echo point. If so, retain its original radial echo wind speed data; otherwise, remove or fill it. The judgment basis is as follows:

[0018] When the window center point original value v ij When it is not 0, that is, it is a valid radar echo point, if the original radial echo wind speed data x′ is less than or equal to the noise removal threshold k1, it indicates that there are few radar echo points close to the window center point, so the original radial echo wind speed data x′ is considered to be singular data. At this time, the new value v' of the window center point ij If the original radial echo wind speed data x′ is greater than the noise removal threshold k1, it indicates that there are many radar echo points close to the center point of the window, so the original radial echo wind speed data x′ should be the normal radial echo wind speed data in the continuous interval. At this time, the new value v' of the center point of the window ij The original value v of the window center point ij , so it is retained;

[0019] When the window center point original value v ij When it is equal to 0, that is, an invalid radar echo point, it should be considered whether the radar echo point is a missing value point, that is, whether the radar echo point should be filled; such as the intermediate value x m If it is greater than or equal to the missing value threshold k2, it means that the frequency of the radar echo point in a certain interval is large and there are many valid radar echo points around it. Therefore, the midpoint value v of the interval corresponding to the radar echo point is set. n Assign it to fill it; such as the middle value x m If it is less than the missing value threshold k2, it means that there is no radar echo point or very few radar echo points in the window M*N, and there are not many valid radar echo points around it. Therefore, the radar echo point is considered to be an invalid radar echo point and no more value is added. The above method is used to judge and process it in turn, and finally all the valid radial wind speed data are obtained.

[0020] In step 3), the specific method of using the above radial wind speed valid data, using the regional growing method to identify wind shear, and outputting the wind shear intensity and wind shear position distribution corresponding to different times is:

[0021] 3.1) converting the effective radial wind speed data obtained in step 2) from the radar polar coordinates into rectangular coordinates to obtain two-dimensional effective radial wind speed data;

[0022] 3.2) The above two-dimensional radial wind speed valid data is stored in the two-dimensional array DATA; at the same time, a result two-dimensional array is constructed, in which a value of 0 indicates initialization, that is, no comparison and identification is performed; a value of 1 and a value of 2 respectively indicate a slight wind shear and a moderate or above wind shear in the identified wind shear zone; a value of 255 indicates a non-wind shear zone after identification;

[0023] 3.3) Construct a SEED seed stack to store seed points; assume that the starting seed point M(x0, y0) is the effective two-dimensional radial wind speed data of the radar center point, and the effective two-dimensional radial wind speed data is always 0; take the starting seed point M(x0, y0) as the center point of the two-dimensional array DATA, compare the difference between the center point and the effective two-dimensional radial wind speed data of its four neighboring points, and then compare the obtained difference with the slight wind shear and moderate and above wind shear warning thresholds in the wind shear intensity standard promulgated by the International Civil Aviation Organization ICAO; if the former is greater than the latter, set the corresponding value in the result two-dimensional array to 1 or 2; if the former is less than the latter, set the corresponding value in the result two-dimensional array to 255;

[0024] 3.4) Take the 4 neighborhood points in the above two-dimensional array as new seed points, compare the difference with the 4 neighborhood points around them respectively, and judge according to the method of the above step 3.3); repeat this step, and set the value of the new seed point to 1 or 2 or 255 each time the neighborhood point comparison is completed, until the difference comparison of all seed points in the two-dimensional array DATA is completed, so as to obtain the wind shear intensity and wind shear position distribution at a certain moment; use this method to identify the wind shear of the two-dimensional radial wind speed valid data at different moments in turn, and finally output the wind shear information of the wind shear intensity and wind shear position distribution corresponding to different moments.

[0025] In step 4), the specific method of dividing multiple areas and issuing wind shear warnings based on the above wind shear information in a temporal and spatial perspective combined with the wind shear intensity is:

[0026] 4.1) Divide the two ends of the airport runway and the glide path into multiple areas in units of 1 nautical mile;

[0027] 4.2) accumulating the wind shear alarm frequencies of different levels by taking the wind shear intensity and wind shear position distribution information at different times obtained in step 3) into a time period of ten minutes;

[0028] 4.3) The area for issuing slight wind shear warning is the area where slight wind shear is identified and one area adjacent to both sides; under normal weather conditions, if slight wind shear is identified in two consecutive areas among all the above areas, and the time density of slight wind shear identification is greater than threshold A, a 20-minute short-time scale slight wind shear warning will be issued in the corresponding area; under special weather conditions, if slight wind shear areas are identified in two consecutive areas among all the above areas, and the time density of slight wind shear identification is greater than threshold B, a 20-minute short-time scale slight wind shear warning will be issued in the corresponding area;

[0029] 4.4) The area for issuing moderate or above wind shear warning is the area where moderate or above wind shear is identified and the two adjacent areas on both sides; under normal weather conditions, if at least one area among all the above areas is identified as moderate or above wind shear area, and the time density of moderate or above wind shear identification is greater than threshold C, a 30-minute medium-time scale moderate or above wind shear warning will be issued in the corresponding area; under special weather conditions, if at least one area among all the above areas is identified as moderate or above wind shear area, and the time density of moderate or above wind shear identification is greater than threshold D, a 30-minute medium-time scale moderate or above wind shear warning will be issued in the corresponding area;

[0030] 4.5) During the issuance of a wind shear warning, wind shear shall be continuously identified; when the triggering warning conditions are met and the identified wind shear is the same as the previously identified wind shear intensity and area, the warning time shall be extended; for a mild wind shear warning, wind shear shall be continuously identified within 10 minutes before the warning ends, and for a moderate or above wind shear warning, wind shear shall be continuously identified within 20 minutes before the warning ends. If the triggering warning conditions are not met, the wind shear warning shall be terminated;

[0031] 4.6) When the identified wind shear is different from the previously identified wind shear intensity and area, or is the same as the previously identified wind shear intensity but different in area, a new wind shear warning is issued; when the identified wind shear is different from the previously identified wind shear intensity but the same in area, the last wind shear warning is revoked and a new wind shear warning is reissued.

[0032] The threshold value A is 8 times / every 10 minutes, the threshold value B is 5 times / every 10 minutes, the threshold value C is 2 times / every 10 minutes, and the threshold value D is 1 time / every 10 minutes.

[0033] The beneficial effects of the present invention are: it can realize reasonable warning, reduce false alarm rate, and improve the guarantee efficiency of meteorological services. First of all, compared with other scanning methods, the laser radar adopts glide path scanning to shorten the scanning cycle. In the actual warning business, the glide path is specially scanned, and the scanning area has targeted concentration, which can improve the efficiency of the warning. Furthermore, the radial echo wind speed data obtained after the glide path scanning is eliminated through quality control to eliminate noise points and fill in missing values, thereby effectively improving the accuracy of the warning. By issuing wind shear warnings from the perspective of intensity combined with time and space, the problem of frequent warnings in the existing warning issuance process is solved, the difference between the number of wind shear warnings provided by the laser radar and the number of wind shears actually encountered by the aircraft is reduced, and the accuracy of the results of the warning issuance is improved. Finally, a complete wind shear warning system of reasonable warning, reasonable correction of warnings, and reasonable cancellation of warnings is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A flow chart of the method for issuing regional wind shear warning based on laser radar provided by the present invention;

[0035] Figure 2 A flow chart of issuing a slight intensity wind shear warning provided in an embodiment of the present invention;

[0036] Figure 3 A flowchart for issuing a moderate or higher intensity wind shear warning provided in an embodiment of the present invention;

[0037] Figure 4 A flowchart for extending and terminating the issuance of a slight intensity wind shear warning under normal and special weather conditions provided by an embodiment of the present invention;

[0038] Figure 5 A flow chart for extending and terminating a moderate or higher intensity wind shear warning under normal and special weather conditions provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention clearer, the implementation scheme of the present invention is further described in detail below in conjunction with the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] In the embodiment of the present invention, by using a laser wind measuring radar to continuously detect the wind field above the aircraft glide path and the airport runway, the wind field information near the target area can be detected in real time at a higher temporal and spatial resolution, so that regional wind shear can be discovered in time and an alarm can be issued.

[0041] like Figure 1 As shown, the method for issuing regional wind shear warning based on laser radar provided by the present invention includes the following steps performed in sequence:

[0042] 1) Set the laser radar's location, scanning mode, scanning angle, and scanning area, use the laser radar to scan the scanning area, and obtain the original radial echo wind speed data of each radar echo point at different times in the entire scanning area;

[0043] The laser radar is deployed at a position more than 200m vertically away from the center line of the airport runway; the laser radar adopts the glide path scanning method; the glide path scanning angle adopts the same elevation angle as the glide path slope. When the aircraft lands and approaches the airport, the glide path slope is 3 degrees, and the scanning angle adopts an elevation angle of 3 degrees. When the aircraft takes off and leaves the airport, the glide path slope is 6 degrees, and the scanning angle adopts an elevation angle of 6°. The scanning area is the aircraft glide path and the air above the airport runway.

[0044] 2) For the above original radial echo wind speed data, the fitting window idea is applied on the basis of the neighborhood frequency method to remove noise and fill in missing values ​​to obtain effective radial wind speed data;

[0045] The specific method is:

[0046] 2.1) Divide the original radial echo wind speed data in the window M*N into n equally spaced intervals, with the interval interval set to Δd and the original value of the window center point set to v ij ;

[0047] 2.2) The frequency of radar echo points in different intervals within the statistical window M*N (x1, x2...x n ) and the original radial echo wind speed data x′ corresponding to the radar echo point, and let x m is the frequency (x1,x2...x n ) and the maximum value of the original radial echo wind speed data x′, v n The maximum value x m The middle value of the corresponding interval; v' ij is the new value of the window center point, the formula is as follows:

[0048]

[0049] In the formula, k1 is the noise removal threshold, k2 is the missing value threshold;

[0050] 2.3) According to the above formula, noise is removed and missing values ​​are filled, and the original radial echo wind speed data x′ of all radar echo points in the window M*N or the maximum value x in the interval is m Compare with the noise removal threshold k1 or the missing value threshold k2 to determine whether it is a valid radar echo point. If so, retain its original radial echo wind speed data; otherwise, remove or fill it. The judgment basis is as follows:

[0051] When the window center point original value vij When it is not 0, that is, it is a valid radar echo point, if the original radial echo wind speed data x′ is less than or equal to the noise removal threshold k1, it indicates that there are few radar echo points close to the window center point, so the original radial echo wind speed data x′ is considered to be singular data. At this time, the new value v' of the window center point ij If the original radial echo wind speed data x′ is greater than the noise removal threshold k1, it indicates that there are many radar echo points close to the center point of the window, so the original radial echo wind speed data x′ should be the normal radial echo wind speed data in the continuous interval. At this time, the new value v' of the center point of the window ij The original value v of the window center point ij , so it is retained;

[0052] When the window center point original value v ij When it is equal to 0, that is, an invalid radar echo point, it should be considered whether the radar echo point is a missing value point, that is, whether the radar echo point should be filled; such as the intermediate value x m If it is greater than or equal to the missing value threshold k2, it means that the frequency of the radar echo point in a certain interval is large and there are many valid radar echo points around it. Therefore, the midpoint value v of the interval corresponding to the radar echo point is set. n Assign it to fill it; such as the middle value x m If it is less than the missing value threshold k2, it means that there is no radar echo point or very few radar echo points in the window M*N, and there are not many valid radar echo points around it. Therefore, the radar echo point is considered to be an invalid radar echo point and no more value is added. The above method is used to judge and process it in turn, and finally all the valid radial wind speed data are obtained.

[0053] 3) Using the above radial wind speed valid data, the regional growing method is used to identify wind shear, and the wind shear intensity and wind shear position distribution corresponding to different times are output;

[0054] The specific method is:

[0055] 3.1) converting the effective radial wind speed data obtained in step 2) from the radar polar coordinates into rectangular coordinates to obtain two-dimensional effective radial wind speed data;

[0056] 3.2) The above two-dimensional radial wind speed valid data is stored in the two-dimensional array DATA; at the same time, a result two-dimensional array is constructed, in which a value of 0 indicates initialization, that is, no comparison and identification is performed; a value of 1 and a value of 2 respectively indicate a slight wind shear and a moderate or above wind shear in the identified wind shear zone; a value of 255 indicates a non-wind shear zone after identification;

[0057] 3.3) Construct a SEED seed stack to store seed points; assume that the starting seed point M(x0, y0) is the effective two-dimensional radial wind speed data of the radar center point, and the effective two-dimensional radial wind speed data is always 0; take the starting seed point M(x0, y0) as the center point of the two-dimensional array DATA, compare the difference between the center point and the effective two-dimensional radial wind speed data of its four neighboring points, and then compare the obtained difference with the slight wind shear and moderate and above wind shear warning thresholds in the wind shear intensity standard promulgated by the International Civil Aviation Organization ICAO; if the former is greater than the latter, set the corresponding value in the result two-dimensional array to 1 or 2; if the former is less than the latter, set the corresponding value in the result two-dimensional array to 255;

[0058] 3.4) Take the 4 neighborhood points in the above two-dimensional array as new seed points, compare the difference with the 4 neighborhood points around them respectively, and judge according to the method of the above step 3.3); repeat this step, and set the value of the new seed point to 1 or 2 or 255 each time the neighborhood point comparison is completed, until the difference comparison of all seed points in the two-dimensional array DATA is completed, so as to obtain the wind shear intensity and wind shear position distribution at a certain moment; use this method to identify the wind shear of the two-dimensional radial wind speed valid data at different moments in turn, and finally output the wind shear information of the wind shear intensity and wind shear position distribution corresponding to different moments.

[0059] 4) Divide multiple areas and issue wind shear warnings based on the above wind shear information in a temporal and spatial perspective combined with wind shear intensity;

[0060] The specific method is:

[0061] 4.1) Divide the two ends of the airport runway and the glide path into multiple areas in units of 1 nautical mile;

[0062] 4.2) accumulating the wind shear alarm frequencies of different levels by taking the wind shear intensity and wind shear position distribution information at different times obtained in step 3) into a time period of ten minutes;

[0063] 4.3) The area for issuing slight wind shear warning is the area where slight wind shear is identified and one area adjacent to both sides; under normal weather conditions, if slight wind shear is identified in two consecutive areas among all the above areas, and the time density of slight wind shear identification is greater than threshold A, a 20-minute short-time scale slight wind shear warning will be issued in the corresponding area; under special weather conditions, if slight wind shear areas are identified in two consecutive areas among all the above areas, and the time density of slight wind shear identification is greater than threshold B, a 20-minute short-time scale slight wind shear warning will be issued in the corresponding area;

[0064] 4.4) The area for issuing moderate or above wind shear warning is the area where moderate or above wind shear is identified and the two adjacent areas on both sides; under normal weather conditions, if at least one area among all the above areas is identified as moderate or above wind shear area, and the time density of moderate or above wind shear identification is greater than threshold C, a 30-minute medium-time scale moderate or above wind shear warning will be issued in the corresponding area; under special weather conditions, if at least one area among all the above areas is identified as moderate or above wind shear area, and the time density of moderate or above wind shear identification is greater than threshold D, a 30-minute medium-time scale moderate or above wind shear warning will be issued in the corresponding area;

[0065] It should be noted that the wind shear warning issuance area is the area where slight wind shear is identified and one area adjacent to both sides, and the area where moderate or above wind shear is identified and two areas adjacent to both sides. This is due to the limitation of the laser radar detection range and the position of the wind shear area identified to span two or more areas. The time density is the accumulated frequency of wind shear alarms of the same level within ten minutes. Under special conditions, it refers to strong winds, wind direction changes, convection, heavy rainfall, etc. At this time, the probability of wind shear is greater than that of normal weather conditions. Therefore, the threshold of the time density of slight wind shear warnings and moderate or above wind shear warnings under special conditions is lower than that of normal conditions, that is, threshold A is greater than threshold B, and threshold C is greater than threshold D.

[0066] According to the statistical results of the wind shear detection test at an international airport in July, August and September 2019: there were 76 wind shear warnings provided by the laser radar wind measurement data, and only 14 of them were verified by the aircraft encountering wind shear events. These warnings are sometimes verified by crew reports, and sometimes not verified by crew reports. In order to reduce the difference between the number of wind shear warnings provided by the laser radar and the number of wind shears actually encountered by the aircraft, and to reduce the false alarm rate, combined with the test statistical results, the present invention provides a reference threshold A of 8 times / every 10 minutes, a threshold B of 5 times / every 10 minutes, a threshold C of 2 times / every 10 minutes, and a threshold D of 1 time / every 10 minutes.

[0067] In addition to the 14 warnings given in the wind shear events reported by the crew, the lidar wind measurement data provided 53 mild wind shear warnings and 9 moderate wind shear warnings, including 47 single mild warnings (within 20 minutes), 4 continuous mild warnings (within 1 hour), 2 continuous mild warnings (more than 1 hour but less than 2 hours), 6 single moderate warnings (within 30 minutes), and 3 continuous moderate warnings (within 1 hour).

[0068] 4.5) During the issuance of a wind shear warning, wind shear shall be continuously identified; when the triggering warning conditions are met and the identified wind shear is the same as the previously identified wind shear intensity and area, the warning time shall be extended; for a mild wind shear warning, wind shear shall be continuously identified within 10 minutes before the warning ends, and for a moderate or above wind shear warning, wind shear shall be continuously identified within 20 minutes before the warning ends. If the triggering warning conditions are not met, the wind shear warning shall be terminated;

[0069] 4.6) When the identified wind shear is different from the previously identified wind shear intensity and area, or is the same as the previously identified wind shear intensity but different in area, a new wind shear warning is issued; when the identified wind shear is different from the previously identified wind shear intensity but the same in area, the last wind shear warning is revoked and a new wind shear warning is reissued.

[0070] For example, if a slight wind shear warning has been issued in the first ten minutes, and a moderate or higher warning condition is identified and triggered in the second ten minutes, the slight wind shear warning will be cancelled and a moderate or higher wind shear warning will be reissued. In particular, if a moderate or higher wind shear warning has been issued in the first ten minutes, and a slight warning condition is subsequently identified and triggered, the moderate or higher wind shear warning will not be cancelled.

[0071] like Figure 2 As shown, the issuing of a slight intensity wind shear warning provided in an embodiment of the present invention is based on a method for issuing a laser radar regional wind shear warning provided in an embodiment of the present invention, and step 4) includes:

[0072] S41: Multiple regions identify wind shear.

[0073] S42: Accumulated frequency of wind shear alarms within ten minutes.

[0074] The cumulative wind shear alarm frequency within ten minutes is the slight wind shear alarm frequency.

[0075] S43a: Determine whether the time density of the slight wind shear alarm frequency is greater than threshold A or B.

[0076] If it is greater than threshold A or B, execute the subsequent steps.

[0077] S44a: A 20-minute short-term scale slight intensity wind shear warning is issued in the corresponding area.

[0078] like Figure 3 As shown, the issuing of moderate and above intensity wind shear warnings provided in the embodiment of the present invention is based on the method for issuing regional wind shear warnings based on laser radar provided in the present invention, and step 4) further includes:

[0079] S41: Multiple regions identify wind shear.

[0080] S42: Accumulated frequency of wind shear alarms within ten minutes.

[0081] The cumulative frequency of wind shear alarms within ten minutes is moderate or above.

[0082] S43b: Determine whether the time density of the frequency of moderate and above wind shear alarms is greater than threshold C or D.

[0083] If it is greater than the threshold C or D, execute the subsequent steps.

[0084] S44b: A moderate or above wind shear warning is issued in the corresponding area on a 30-minute time scale.

[0085] like Figure 4 As shown, the method for extending and terminating the issuance of a slight wind shear warning under normal and special weather conditions provided by the embodiment of the present invention is based on the issuance of a slight wind shear warning provided by the embodiment of the present invention, and S44a includes:

[0086] S44a1: Wind shear continues to be identified in the same area.

[0087] S44a2: Cumulative frequency of slight wind shear alarms in the 1st + nth ten minutes.

[0088] The value of n is 1, 2, 3, etc., and the initial value is 1. For example, when n is 1, it means that the frequency of the second 10-minute slight wind shear alarm begins to be accumulated.

[0089] S44a3: Determine whether the time density is greater than threshold A or B.

[0090] If the time density of the slight wind shear alarm frequency is greater than threshold A or B, it means that the time density of the second ten minutes is also greater than threshold A or B, and jump to step S44a4; otherwise, it means that the alarm triggering conditions are not met in the second ten minutes, and jump to step S44a5.

[0091] S44a4: Issue a 20+10*n minute light intensity wind shear warning.

[0092] For example, if the value of n is 1, it means that a 30-minute light wind shear warning is issued. Then, wind shear is continuously identified in the third ten minutes, and the process jumps to step S44a2 to start accumulating the frequency of light wind shear warnings in the third ten minutes, and the cycle repeats until the threshold value A or B is not reached, and the warning is terminated.

[0093] S44a5: End this alarm.

[0094] The condition for ending this alarm is that the time density is less than threshold A or B within 10 minutes before the alarm ends, and the triggering alarm condition is not met, so this wind shear alarm ends.

[0095] like Figure 5 As shown, the method for extending and ending the issuance of moderate and above wind shear warnings under normal and special weather conditions provided by the embodiment of the present invention is based on the issuance of moderate and above wind shear warnings provided by the embodiment of the present invention, and S44b includes:

[0096] S44b1: Wind shear continues to be identified in the same area.

[0097] S44b2: Cumulative frequency of moderate and above wind shear alarms in the 1st + nth ten minutes.

[0098] S44b3: Determine whether the time density is greater than the threshold C (D).

[0099] If the time density of the frequency of moderate and above wind shear alarms is greater than threshold C or D, jump to step S44b4, otherwise jump to step S44b5.

[0100] S44b4: Issue a 30+10*n minute moderate or above wind shear warning.

[0101] S44b5: Cumulative frequency of moderate and above wind shear alarms in the 2nd + nth ten-minute period.

[0102] S44b6: Determine whether the time density is greater than the threshold C (D).

[0103] If the time density of the frequency of moderate and above wind shear alarms is greater than threshold C or D, jump to step S44b7, otherwise jump to step S44b8.

[0104] S44b7: Issued for 30+10*(1+n) minutes of light wind.

[0105] S44b8: End this alarm.

[0106] If the time density of two consecutive ten-minute moderate or above wind shear alarms is less than threshold C or D, the alarm will end.

[0107] It should be noted that the repeated description of extending and ending the issuance of moderate and above wind shear warnings under normal and special weather conditions provided in the embodiment of the present invention and the extending and ending the issuance of slight wind shear warnings under normal and special weather conditions provided in the above-mentioned embodiment will not be repeated here for the sake of brevity.

[0108] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for issuing regional wind shear warnings based on laser radar, characterized in that: The method for issuing regional wind shear warning based on laser radar includes the following steps performed in sequence: 1) Set the laser radar's location, scanning mode, scanning angle, and scanning area, use the laser radar to scan the scanning area, and obtain the original radial echo wind speed data of each radar echo point at different times in the entire scanning area; 2) For the above original radial echo wind speed data, the fitting window idea is applied on the basis of the neighborhood frequency method to remove noise and fill in missing values ​​to obtain effective radial wind speed data; 3) Using the above radial wind speed valid data, the regional growing method is used to identify wind shear, and the wind shear intensity and wind shear position distribution corresponding to different times are output; 4) Divide multiple areas and issue wind shear warnings based on the above wind shear information in a temporal and spatial perspective combined with wind shear intensity; In step 1), the specific method of setting the laser radar's setting position, scanning mode, scanning angle and scanning area is: The laser radar is deployed at a position more than 200m vertically away from the center line of the airport runway; the laser radar adopts the glide path scanning method; the glide path scanning angle adopts the same elevation angle as the glide path slope. When the aircraft lands and approaches, the glide path slope is 3 degrees, and the scanning angle adopts an elevation angle of 3 degrees. When the aircraft takes off and leaves, the glide path slope is 6 degrees, and the scanning angle adopts an elevation angle of 6 degrees. The scanning area is the aircraft glide path and the air above the airport runway; In step 2), the specific method of removing noise and filling missing values ​​by applying the fitting window idea to the above original radial echo wind speed data based on the neighborhood frequency method to obtain valid radial wind speed data is as follows: 2.1) Divide the original radial echo wind speed data in the window M*N into n equally spaced intervals, with the interval interval set to Δd and the original value of the window center point set to v ij ; 2.2) The frequency of radar echo points in different intervals within the statistical window M*N is x1, x2...x n and the original radial echo wind speed data x′ corresponding to the radar echo point, and let x m is the frequency x1,x2...x n and the maximum value of the original radial echo wind speed data x′, v n The maximum value x m The middle value of the corresponding interval; v′ ij is the new value of the window center point, the formula is as follows: In the formula, k1 is the noise removal threshold, k2 is the missing value threshold; 2.3) According to the above formula, noise is removed and missing values ​​are filled, and the original radial echo wind speed data x′ of all radar echo points in the window M*N or the maximum value x in the interval is m Compare with the noise removal threshold k1 or the missing value threshold k2 to determine whether it is a valid radar echo point. If so, retain its original radial echo wind speed data; otherwise, remove or fill it. The judgment basis is as follows: When the window center point original value v ij When it is not 0, that is, it is a valid radar echo point, if the original radial echo wind speed data x′ is less than or equal to the noise removal threshold k1, it indicates that there are few radar echo points close to the window center point, so the original radial echo wind speed data x′ is considered to be singular data. At this time, the new value v' of the window center point ij If the original radial echo wind speed data x′ is greater than the noise removal threshold k1, it indicates that there are many radar echo points close to the center point of the window, so the original radial echo wind speed data x′ should be the normal radial echo wind speed data in the continuous interval. At this time, the new value v' of the center point of the window ij The original value v of the window center point ij , so it is retained; When the original value of the window center point vij is equal to 0, that is, it is an invalid radar echo point, it should be considered whether the radar echo point is a missing value point, that is, whether the radar echo point should be filled; if the intermediate value x m If it is greater than or equal to the missing value threshold k2, it means that the frequency of the radar echo point in a certain interval is large and there are many valid radar echo points around it. Therefore, the midpoint value v of the interval corresponding to the radar echo point is set. n Assign it to fill it; such as the middle value x m If it is less than the missing value threshold k2, it means that there is no radar echo point or very few radar echo points in the window M*N, and there are not many valid radar echo points around it. Therefore, the radar echo point is considered to be an invalid radar echo point and no more value is added. The above method is used to judge and process it in turn, and finally all the valid radial wind speed data are obtained; In step 3), the specific method of using the above radial wind speed valid data, using the regional growing method to identify wind shear, and outputting the wind shear intensity and wind shear position distribution corresponding to different times is: 3.1) converting the effective radial wind speed data obtained in step 2) from the radar polar coordinates into rectangular coordinates to obtain two-dimensional effective radial wind speed data; 3.2) The above two-dimensional radial wind speed valid data is stored in the two-dimensional array DATA; at the same time, a result two-dimensional array is constructed, in which a value of 0 indicates initialization, that is, no comparison and identification is performed; a value of 1 and a value of 2 respectively indicate a slight wind shear and a moderate or above wind shear in the identified wind shear zone; a value of 255 indicates a non-wind shear zone after identification; 3.3) Construct a SEED seed stack to store seed points; assume that the starting seed point M(x0, y0) is the effective two-dimensional radial wind speed data of the radar center point, and the effective two-dimensional radial wind speed data is always 0; take the starting seed point M(x0, y0) as the center point of the two-dimensional array DATA, compare the difference between the center point and the effective two-dimensional radial wind speed data of its four neighboring points, and then compare the obtained difference with the slight wind shear and moderate and above wind shear warning thresholds in the wind shear intensity standard promulgated by the International Civil Aviation Organization ICAO; if the former is greater than the latter, set the corresponding value in the result two-dimensional array to 1 or 2; if the former is less than the latter, set the corresponding value in the result two-dimensional array to 255; 3.4) Take the 4 neighborhood points in the above two-dimensional array as new seed points, perform difference comparison with the 4 surrounding neighborhood points respectively, and make judgment according to the method of the above step 3.3); repeat this step, and set the value of the new seed point to 1 or 2 or 255 each time the neighborhood point comparison is completed, until the difference comparison of all seed points in the two-dimensional array DATA is completed, so as to obtain the wind shear intensity and wind shear position distribution at a certain moment; use this method to identify the wind shear of the two-dimensional radial wind speed valid data at different moments, and finally output the wind shear information of the wind shear intensity and wind shear position distribution corresponding to different moments; In step 4), the specific method of dividing multiple areas and issuing wind shear warnings based on the above wind shear information in a temporal and spatial perspective combined with the wind shear intensity is: 4.1) Divide the two ends of the airport runway and the glide path into multiple areas in units of 1 nautical mile; 4.2) accumulating the wind shear alarm frequencies of different levels by taking the wind shear intensity and wind shear position distribution information at different times obtained in step 3) into a time period of ten minutes; 4.3) The area where the slight wind shear warning is issued is the area where slight wind shear is identified and an area immediately adjacent to both sides; under normal weather conditions, if slight wind shear is identified in two consecutive areas among the above multiple areas, and the time density of slight wind shear identification is greater than threshold A, a 20-minute short-time scale slight intensity wind shear warning will be issued in the corresponding area; under special weather conditions, if slight wind shear areas are identified in two consecutive areas among the above multiple areas, and the time density of slight wind shear identification is greater than threshold B, a 20-minute short-time scale slight intensity wind shear warning will be issued in the corresponding area; 4.4) The area for issuing moderate or above wind shear warnings is the area where moderate or above wind shear is identified and the two adjacent areas on both sides; under normal weather conditions, if at least one area among the above multiple areas is identified as a moderate or above wind shear area, and the time density of moderate or above wind shear identification is greater than the threshold value C, a 30-minute medium-time scale moderate or above wind shear warning will be issued in the corresponding area; under special weather conditions, if at least one area among the above multiple areas is identified as a moderate or above wind shear area, and the time density of moderate or above wind shear identification is greater than the threshold value D, a 30-minute medium-time scale moderate or above wind shear warning will be issued in the corresponding area; 4.5) During the issuance of a wind shear warning, wind shear shall be continuously identified; when the triggering warning conditions are met and the identified wind shear is the same as the previously identified wind shear intensity and area, the warning time shall be extended; for a mild wind shear warning, wind shear shall be continuously identified within 10 minutes before the warning ends, and for a moderate or above wind shear warning, wind shear shall be continuously identified within 20 minutes before the warning ends. If the triggering warning conditions are not met, the wind shear warning shall be terminated; 4.6) When the identified wind shear is different from the previously identified wind shear intensity and area, or is the same as the previously identified wind shear intensity but different in area, a new wind shear warning is issued; when the identified wind shear is different from the previously identified wind shear intensity but the same in area, the last wind shear warning is revoked and a new wind shear warning is reissued.

2. The method for issuing regional wind shear warning based on laser radar according to claim 1, characterized in that: The threshold value A is 8 times / every 10 minutes, the threshold value B is 5 times / every 10 minutes, the threshold value C is 2 times / every 10 minutes, and the threshold value D is 1 time / every 10 minutes.

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