Meteorological safety risk assessment method and device in low-altitude flight of rescue aircraft

Abstract

The invention relates to a meteorological safety risk assessment method and device for a rescue aircraft in low-altitude flight, which considers the actual meteorological conditions of a sea area near a large bay area of Guangdong Hong Kong Australian, focuses on selecting wind (shear) and visibility as key meteorological elements depending on a stereoscopic observation network of the area, pays attention to weather such as severe convection and typhoon, designs meteorological condition assessment factors, and provides a meteorological safety risk assessment method for the rescue aircraft in low-altitude flight. A low-altitude flight index which comprehensively reflects meteorological conditions and can serve different aircrafts is designed, an AFI calculation method is formed, finally, AFI is calculated by applying forecast data of a mesoscale numerical mode CMAGD3km in a high-resolution region in South China, the AFI is applied to a low-altitude flight meteorological assessment forecast process, and the safety of search and rescue flight of a rescue aircraft is guaranteed. According to the method, the meteorological safety risk of the rescue aircraft in the low-altitude flight is evaluated, severe convection weather, typhoon weather and rainfall weather in the low-altitude flight period are fully considered, and targeted safety risk evaluation is carried out on the rescue flight of different rescue aircrafts under the severe weather condition.

Description

Technical Field

[0001] The present invention relates to the technical field related to general aviation meteorological safety, and in particular to a method and device for assessing meteorological safety risks of a rescue aircraft during low-altitude flight. Background Art

[0002] Flight activities in low-altitude airspace are easily affected by terrain and meteorological conditions. Weather phenomena such as low visibility, low clouds, rainfall, thunderstorms, hail, and low-altitude wind shear will affect the normality and safety of low-altitude flight.

[0003] Rescue flights such as disaster relief are mostly carried out at low altitudes, and rescue aircraft flying at low altitudes is one of the most common scenarios for general aviation low-altitude flight activities. The existing methods for assessing the meteorological safety risks of general aviation aircraft in low-altitude flights are mainly divided into the following categories: one is to assess the meteorological safety risks of a certain aspect of low-altitude flight activities, mainly focusing on the assessment of collision risks or the risk of drone crashes, and lacking a comprehensive assessment of meteorological safety risks during flight; one is to use civil meteorological information for meteorological safety risk assessment, but the accuracy, frequency and accuracy of civil meteorological intelligence are not high, and it is difficult to meet the needs of meteorological safety risk assessment in low-altitude flights with complex and fast-changing weather; one is to assess the meteorological safety risks of general aviation aircraft under normal flight, but lacks a comprehensive assessment of the meteorological safety risks of rescue aircraft under severe weather conditions.

[0004] The assessment methods for meteorological safety risks in these types of low-altitude flights have the following main defects: (1) The accuracy and frequency of the meteorological information used are not high, and they mainly focus on the actual conditions and forecasts of large-scale short-term weather, which is difficult to meet the needs of low-altitude flights for high-precision weather conditions and weather forecasts; (2) They mainly focus on the meteorological safety risks of take-off and landing points, as well as limited meteorological elements and weather phenomena, and do not give enough consideration to the comprehensive meteorological safety risks and various severe weather conditions during low-altitude flights; (3) The focus of the assessment is on the meteorological safety risks under normal flight conditions, and there is a lack of meteorological safety risk assessment for rescue flights under severe weather conditions. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the deficiencies of the prior art and to provide a method and device for assessing meteorological safety risks of a rescue aircraft during low-altitude flight.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] Specifically, a method for assessing meteorological safety risks of rescue aircraft during low-altitude flight is proposed, including the following:

[0008] Obtain historical data of the target area, extract influencing factors from the historical data through regression analysis method, and calculate effective weight coefficients of wind shear under the background of typhoon weather and severe convective weather, as well as effective weight coefficients of visibility at all levels when there is rain or no rain;

[0009] The wind shear prediction equation is established according to the effective weight coefficient of wind shear, and the visibility prediction equation is established according to the effective weight coefficient of each level of visibility;

[0010] Using the forecast data of the mesoscale numerical model CMA_GD_3km, the wind shear forecast equation is selected to calculate the wind shear, so as to make a forecast correction of the high-altitude wind speed;

[0011] Using the forecast data of the mesoscale numerical model CMA_GD_3km, the visibility forecast equation is selected to calculate the visibility, so as to make a forecast correction of the visibility;

[0012] Based on the influencing factors, a low-altitude flight index AFI is defined, and the AFI is graded and combined with preset meteorological elements to obtain a discrimination standard;

[0013] The low-altitude flight index is calculated based on the calculated wind shear, forecast-corrected high-altitude wind speed, and forecast-corrected visibility, and the low-altitude flight meteorological safety risk assessment is completed by comparing the calculated result with the judgment standard.

[0014] Further, specifically, the wind shear prediction equation established includes,

[0015] (1) Lower-level wind shear: from ground level to 800 meters

[0016] Typhoon landfall affects the coastal areas of eastern Guangdong

[0017] y=4.462+0.026x 2 -1.3×10 -7 e x (1.1)

[0018] Typhoon landfall affects the coastal areas of central Guangdong

[0019] y=6.089-0.4643x+3.385lnx(1.2)

[0020] Typhoon landfall affects the coastal areas of western Guangdong

[0021] y=3.555+0.041x 2 +3.516lnx(1.3)

[0022] Severe convective weather

[0023] y=6.639+0.0049x 2+3×10 -6 e x (1.4)

[0024] (2) Upper-level wind shear: ranges from 800m to 1500m

[0025] Typhoon landfall affects the coastal areas of eastern Guangdong

[0026] y=4.462+0.748x-0.022x 2 (1.5)

[0027] Typhoon landfall affects the coastal areas of central Guangdong

[0028] y=2.788+0.631x-1.2×10 -12 e x (1.6)

[0029] Typhoon landfall affects the coastal areas of western Guangdong

[0030] y=3.621+2.453x-5.684lnx+2×10 -7 e x (1.7)

[0031] Severe convective weather

[0032] y=5.321+0.126x 2 -1.657×10 -7 e x (1.8);

[0033] Among them, x represents the wind speed 10m above the ground, and y represents the wind shear.

[0034] Further, specifically, the established visibility prediction equation includes:

[0035] (1) When there is no rain

[0036] Level 1: T<23℃, V<6m / s, T-Td: 1.5~2℃

[0037] y=6815.768+262.5165V-32.48V 2 -134.946lnV-138.127e (T-Td) (1.9)

[0038] Level 2: T<23℃, V<6m / s, T-Td: 1~1.5℃

[0039] y=4027.295-81.8941T+2.0587T 2 (1.10)

[0040] Level 3: T<23℃, V<6m / s, T-Td: 0.7~1℃

[0041] y=1318.762+1132.843(T-Td)+1.442T 2 -572.87(T-Td) 2 +172.09e (T-Td) -170.134ln(T-Td)(1.11)

[0042] Level 4: T<23℃, V<6m / s, T-Td: 0~0.7℃

[0043] y=1037.97(T-Td)+1.276×10 -8 e T -1063.814(T-Td) 2 +407.651e (T-Td) -157.137ln(T-Td)(1.12)

[0044] (2) When it rains

[0045] Level 1: T<23℃, V: 3~6m / s, T-Td: 1.5~2℃

[0046] y=4385.699-206.338T+1487.429(T-Td)+

[0047] 1261.225lnT-426.51ln(T-Td)(1.13)

[0048] Level 2: T<23℃, V: 2.5~3m / s, T-Td: 1~1.5℃

[0049] y=3285.213+414.23(T-Td)(1.14)

[0050] Level 3: T<23℃, V: 2~2.5m / s, T-Td: 0.7~1℃

[0051] y=1549.856-202.5T+41.1833V+323.9697(T-Td)+

[0052] 4.078T 2 +866.226lnT-0.0525ln(T-Td)(1.15)

[0053] Level 4: T < 23 °C, V: 0 ~ 2 m / s, T-Td: 0 ~ 0.7 °C

[0054] y=99.65V+591.669(T-Td)-16.1V 2 -358.885(T-Td) 2 (1.16);

[0055] Among them, y is visibility, T is ground temperature, V is wind speed at 10m above ground, and Td is ground dew point temperature.

[0056] Furthermore, specifically, using the forecast data of the mesoscale numerical model CMA_GD_3km, the wind shear forecast equation is selected to calculate the wind shear, thereby making a forecast correction for the high-altitude wind speed, including:

[0057] Based on the mesoscale numerical model CMA_GD_3km, determine whether there is a typhoon landing or severe convective weather during the forecast period. If there is no impact, the initial data of wind speed and wind shear are used;

[0058] If the forecast period is affected by severe convective weather, select equations (1.4) and (1.8) to calculate the lower-layer wind shear and upper-layer wind shear; if the forecast period is affected by a typhoon landing, select the corresponding equations (1.1-1.3) and (1.5-1.7) to calculate the lower-layer wind shear and upper-layer wind shear according to whether the typhoon lands on the eastern Guangdong coast, the central Guangdong coast, or the western Guangdong coast;

[0059] C3: The calculated lower and upper wind shears are used to correct the high-altitude wind speeds at 800m and 1500m using the ground 10m wind speed correction mode; the calculation relationship between the lower and upper wind shears and the corresponding layer wind speeds is as follows: WS 10m-800m +V 10m =V 800m (1.17)

[0060] WS 800m-1500m +V 800m =V 1500m (1.18);

[0061] Where WS is wind shear, V is wind speed, and the subscript represents a certain layer height or between two layers height, where 10m-800m represents the lower layer, and 800m-1500m represents the upper layer.

[0062] Further, specifically, determine whether there is a typhoon landing or severe convective weather during the forecast period, including:

[0063] Determine whether the echo reflectivity is greater than 50dBZ during the forecast period. If so, it means that there is a typhoon landing or severe convective weather.

[0064] Furthermore, specifically, using the forecast data of the mesoscale numerical model CMA_GD_3km, the visibility forecast equation is selected to calculate the visibility, thereby making a forecast correction of visibility, including:

[0065] Based on the mesoscale numerical model CMA_GD_3km, determine whether the initial visibility field needs to be corrected. If no correction is needed, the initial visibility data is used;

[0066] If correction is required, determine whether there is rain during the forecast period. When there is no rain, select equations (1.9~1.12) to calculate the corrected visibility. When there is rain, select equations (1.13~1.16) to calculate the corrected visibility.

[0067] The present invention also proposes a device for assessing meteorological safety risks of a rescue aircraft during low-altitude flight, comprising the following:

[0068] A data acquisition module is used to acquire historical data of a target area, extract influencing factors from the historical data by regression analysis, and calculate effective weight coefficients of wind shear under the background of typhoon weather and severe convective weather, as well as effective weight coefficients of visibility at all levels when there is rain or no rain;

[0069] A forecast equation establishment module is used to establish a forecast equation for wind shear according to an effective weight coefficient of wind shear, and to establish a forecast equation for visibility according to effective weight coefficients of various levels of visibility;

[0070] The first forecast correction module is used to use the forecast data of the mesoscale numerical model CMA_GD_3km to select the wind shear forecast equation to calculate the wind shear, thereby correcting the forecast of the high-altitude wind speed;

[0071] The second forecast correction module is used to use the forecast data of the mesoscale numerical model CMA_GD_3km to select the visibility forecast equation to calculate the visibility, so as to make forecast corrections to the visibility;

[0072] A discrimination criterion definition module, used to define a low-altitude flight index AFI based on the influencing factors, and to classify and combine the AFI with preset meteorological elements to obtain a discrimination criterion;

[0073] The safety risk assessment module is used to calculate the low-altitude flight index based on the calculated wind shear, the forecast corrected high-altitude wind speed, and the forecast corrected visibility to obtain the calculation results, and complete the low-altitude flight meteorological safety risk assessment by comparing the calculation results with the judgment criteria.

[0074] The beneficial effects of the present invention are:

[0075] The present invention proposes a method and device for assessing meteorological safety risks of rescue aircraft during low-altitude flight, using the forecast data of the South China high-resolution regional mesoscale numerical model CMA_GD_3km, taking full account of severe convective weather, typhoon weather and precipitation weather during low-altitude flight, and conducting targeted safety risk assessments on rescue flights of different rescue aircraft under severe weather conditions. The main advantages are:

[0076] 1) The regression analysis method was used to analyze the ground wind speed, high-altitude wind speed and wind shear in typhoon weather and severe convective weather in historical data, and the visibility in weather with or without precipitation was analyzed. The effective weight coefficient was obtained and the forecast equations for wind shear and visibility were established. This method comprehensively considered the meteorological safety risks of rescue flights.

[0077] 2) The use of the high-precision regional mesoscale numerical model CMA_GD_3km and the use of forecast equations to correct and revise the model's upper-air wind speed and visibility not only improves the precision and accuracy of the forecast assessment, but also improves the stability of the forecast assessment.

[0078] 3) The low-altitude flight index AFI was defined to make meteorological safety risk assessment more direct and operational. The introduction of the AFI index also provides an important reference for the meteorological safety risk assessment of low-altitude flights of general aviation aircraft other than rescue aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The above and other features of the present disclosure will become more apparent by describing in detail the embodiments shown in the accompanying drawings. The same reference numerals in the accompanying drawings of the present disclosure represent the same or similar elements. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure. For those skilled in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work. In the accompanying drawings:

[0080] Figure 1 Shown is a flow chart of the forecast correction of high-altitude wind speed in the present invention;

[0081] Figure 2 Shown is a flow chart of performing forecast correction of visibility in the present invention;

[0082] Figure 3 The figure shows the visibility (unit: km) and weather phenomenon observation map of Guangdong Province at 3:00 a.m. on March 13 in one embodiment of the present invention;

[0083] Figure 4 Shown is a visibility forecast map (unit: km) of the mesoscale numerical model CMA_GD_3km at 00:00 (Beijing time) on March 13 in one embodiment of the present invention;

[0084] Figure 5 The figure shows the forecast of the lower-level AFI of the rescue helicopter (left figure) and the UAV (right figure) by the CMA_GD_3km model at 00:00 on March 13 in one embodiment of the present invention;

[0085] Figure 6 Shown is a mosaic of radar echo combination reflectivity in Guangdong Province at 20:00 on March 13 (unit: dBZ) in one embodiment of the present invention;

[0086] Figure 7 The figure shows the forecast of the combined reflectivity at 20:00 on March 13 by the CMA_GD_3km model in one embodiment of the present invention (unit: dBZ);

[0087] Figure 8 The figure shows the forecast of the rescue helicopter lower low-altitude flight index AFI at 20:00 on March 13 by the CMA_GD_3km model in one implementation of the present invention. DETAILED DESCRIPTION

[0088] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0089] Embodiment 1, the present invention proposes a method for assessing meteorological safety risks of a rescue aircraft during low-altitude flight, comprising the following steps:

[0090] Obtain historical data of the target area, extract influencing factors from the historical data through regression analysis method, and calculate effective weight coefficients of wind shear under the background of typhoon weather and severe convective weather, as well as effective weight coefficients of visibility at all levels when there is rain or no rain;

[0091] Specifically in this step,

[0092] The historical data mainly include ground meteorological observation data and high-altitude meteorological sounding data from 2013 to 2019, relevant data on typhoons that affected or landed on the land and sea of ​​Guangdong from 2013 to 2019, data on severe convective weather processes that affected the land and sea of ​​Guangdong from 2013 to 2019, and data on low visibility processes on land and sea in Guangdong from December to April of the following year from 2015 to 2019.

[0093] The process of analyzing and determining the influencing factors and weights of wind shear by regression analysis is as follows:

[0094] (1) Analyze the annual variation characteristics of the low-altitude wind field in the region using historical data. Using ground meteorological observation data and high-altitude meteorological sounding data from 2013 to 2019, statistically analyze the low-altitude wind field on the land and sea surface of Guangdong from 2013 to 2019 to obtain the annual variation characteristics of the low-altitude wind field.

[0095] (2) Analyze the changing characteristics of low-altitude wind fields under the influence of typhoon weather and severe convective weather from 2013 to 2019, and distinguish different weather types. Assume that the influencing factors are mainly composed of functions of wind speed 10 m above the ground (i.e., ground wind speed), including the first power x, the second power x 2 , index e x , logarithm lnx and other factors, and then use ground wind speed x as the independent variable and wind shear y as the dependent variable for regression fitting. Finally, we get the factors x, x 2 、e x , lnx weight coefficients, and reliability tests were performed on the weight coefficients of each factor. Factors whose weight coefficients passed the 95% reliability test were retained, and factors that failed the test were excluded.

[0096] (3) Perform regression fitting again with each factor whose weight coefficient has passed the test, and perform reliability test again. Keep the factors whose weight coefficient has passed the test, and exclude the factors whose weight coefficient has not passed the test. Repeat the above process until all the weight coefficients of each factor obtained by regression fitting pass the reliability test. At this time, each factor is the final influencing factor, and their weight coefficient is the effective weight coefficient. For example, when the strong convective weather affects the final influencing factor, the quadratic x 2 and exponent e x The weight coefficients have passed the 95% confidence test and are effective weight coefficients for wind shear.

[0097] The process of analyzing and determining the influencing factors and weights of visibility through regression analysis is as follows:

[0098] (1) Analyze the annual variation characteristics of visibility in the region using historical data. Using the ground meteorological observation data from 2013 to 2019 (including visibility, ground temperature, ground wind speed, ground temperature dew point difference and other meteorological elements), the relationship between visibility y and ground temperature T, ground wind speed V, and ground temperature dew point difference T-Td from 2013 to 2019 was statistically analyzed to obtain the annual variation characteristics of visibility.

[0099] (2) Analyze the visibility change characteristics under the low visibility process from 2013 to 2019, and distinguish between the situation of no rain / rain and the level of visibility. It is assumed that the influencing factors are mainly composed of the functions of ground temperature T, ground wind speed V, and ground temperature dew point difference T-Td, including the first power x, the second power x 2 , index e x, logarithm lnx and other factors, with visibility y as the dependent variable, and multiple regression fitting is performed. Finally, the factors x, x of T, V, and T-Td are obtained. 2 、e x , lnx weight coefficients, and reliability tests were performed on the weight coefficients of each factor. Factors whose weight coefficients passed the 95% reliability test were retained, and factors that failed the test were excluded.

[0100] (3) Perform regression fitting again with the factors whose weight coefficients have passed the test, and perform reliability test again. Keep the factors whose weight coefficients have passed the test, and exclude the factors whose weight coefficients have not passed the test. Repeat the above process until all the weight coefficients of the factors obtained by regression fitting pass the reliability test. At this time, the factors are the final influencing factors, and their weight coefficients are the effective weight coefficients of visibility.

[0101] The wind shear prediction equation is established according to the effective weight coefficient of wind shear, and the visibility prediction equation is established according to the effective weight coefficient of each level of visibility;

[0102] Using the forecast data of the mesoscale numerical model CMA_GD_3km, the wind shear forecast equation is selected to calculate the wind shear, so as to make a forecast correction of the high-altitude wind speed;

[0103] Using the forecast data of the mesoscale numerical model CMA_GD_3km, the visibility forecast equation is selected to calculate the visibility, so as to make a forecast correction of the visibility;

[0104] Based on the influencing factors, a low-altitude flight index AFI is defined, and the AFI is graded and combined with preset meteorological elements to obtain a discrimination standard;

[0105] Specifically, using factors such as surface wind, high-altitude wind, wind shear, visibility, and other factors, supplemented by considering typhoons, severe convection, precipitation and other weather conditions, a low-altitude flight index (AFI) is defined to comprehensively reflect whether the meteorological conditions are suitable for low-altitude flight and operations of rescue aircraft. The classification and description of the low-altitude flight index (AFI) are shown in Table 2.

[0106] Table 2: Classification and description of AFI

[0107] grade AFI Range illustrate Level 1 0-20 No impact Level 2 20-40 Mild impact, average flying difficulty Level 3 40-60 Moderate impact, difficult to fly Level 4 60-100 Serious impact, high risk of loss of control

[0108] For two types of rescue aircraft (S-67D rescue helicopter and rotary-wing UAV), the classification ranges of ground wind, high-altitude wind, wind shear, and visibility meteorological elements are designed and combined with the AFI index. The AFI classification of the two types of rescue aircraft and the classification combination of corresponding meteorological elements are shown in Tables 3 and 4.

[0109] Table 3: AFI classification of S-76D rescue helicopter and the classification range of corresponding meteorological elements

[0110] AFI Range Visibility(m) Wind speed (m / s) Wind shear (m / s) 0-20 5000-10000 0-7 0-3 20-40 5000-3000 7-11 3-6 40-60 3000-1000 11-17.1 6-9 60-100 1000-0 17.1-24.4 9-15

[0111] Note: 1. When visibility is ≥ 10,000 meters, AFI is 0; 2. When wind speed is ≥ 24.4 m / s, or wind shear is ≥ 15 m / s, AFI is 100.

[0112] Table 4: AFI classification of rotary-wing UAVs and the classification range of corresponding meteorological elements

[0113] AFI Range Visibility(m) Wind speed (m / s) Wind shear (m / s) 0-20 7000-10000 0-5.5 0-2 20-40 7000-4000 5.5-8 2-4 40-60 4000-1000 8-11 4-6 60-100 1000-0 11-17.1 6-12

[0114] Note: 1. When visibility is ≥ 10,000 meters, AFI is 0; 2. When wind speed is ≥ 17.1 m / s, or wind shear is ≥ 12 m / s, AFI is 100.

[0115] The low-altitude flight index is calculated based on the calculated wind shear, forecast-corrected high-altitude wind speed, and forecast-corrected visibility, and the low-altitude flight meteorological safety risk assessment is completed by comparing the calculated result with the judgment standard.

[0116] Specifically,

[0117] The corrected ground 10m wind, 800m wind, 1500m wind, lower-layer wind shear, upper-layer wind shear and visibility meteorological elements are referred to Table 3 or Table 4 according to the type of rescue aircraft to obtain the AFI classification of each meteorological element.

[0118] The AFI grades of each meteorological element are compared, and the largest grade is taken as the final AFI index.

[0119] Substitute the final AFI index into Table 2 to complete the low-altitude flight meteorological safety risk assessment of the rescue aircraft.

[0120] The evaluation method of the present invention utilizes the AFI index, which can reflect whether the rescue aircraft is suitable for low-altitude flight and operation under different flight meteorological conditions, and provides an evaluation of meteorological safety risks for the low-altitude flight of the rescue aircraft.

[0121] As a preferred embodiment of the present invention, specifically, the wind shear prediction equation established includes:

[0122] (1) Lower-level wind shear: from ground level to 800 meters

[0123] Typhoon landfall affects the coastal areas of eastern Guangdong

[0124] y=4.462+0.026x 2 -1.3×10 -7 e x (1.1)

[0125] Typhoon landfall affects the coastal areas of central Guangdong

[0126] y=6.089-0.4643x+3.385lnx(1.2)

[0127] Typhoon landfall affects the coastal areas of western Guangdong

[0128] y=3.555+0.041x 2 +3.516lnx(1.3)

[0129] Severe convective weather

[0130] y=6.639+0.0049x 2 +3×10 -6 e x (1.4)

[0131] (2) Upper-level wind shear: ranges from 800m to 1500m

[0132] Typhoon landfall affects the coastal areas of eastern Guangdong

[0133] y=4.462+0.748x-0.022x 2 (1.5)

[0134] Typhoon landfall affects the coastal areas of central Guangdong

[0135] y=2.788+0.631x-1.2×10 -12 e x (1.6)

[0136] Typhoon landfall affects the coastal areas of western Guangdong

[0137] y=3.621+2.453x-5.684lnx+2×10 -7 e x (1.7)

[0138] Severe convective weather

[0139] y=5.321+0.126x 2 -1.657×10 -7 e x (1.8);

[0140] Among them, x represents the wind speed 10m above the ground, and y represents the wind shear.

[0141] Further, specifically, the established visibility prediction equation includes:

[0142] (1) When there is no rain

[0143] Level 1: T<23℃, V<6m / s, T-Td: 1.5~2℃

[0144] y=6815.768+262.5165V-32.48V 2 -134.946lnV-138.127e (T-Td) (1.9)

[0145] Level 2: T<23℃, V<6m / s, T-Td: 1~1.5℃

[0146] y=4027.295-81.8941T+2.0587T 2 (1.10)

[0147] Level 3: T<23℃, V<6m / s, T-Td: 0.7~1℃

[0148] y=1318.762+1132.843(T-Td)+1.442T 2 -572.87(T-Td) 2 +172.09e (T-Td) -170.134ln(T-Td)(1.11)

[0149] Level 4: T<23℃, V<6m / s, T-Td: 0~0.7℃

[0150] y=1037.97(T-Td)+1.276×10 -8 e T -1063.814(T-Td) 2 +407.651e (T-Td) -157.137ln(T-Td)(1.12)

[0151] (2) When it rains

[0152] Level 1: T<23℃, V: 3~6m / s, T-Td: 1.5~2℃

[0153] y=4385.699-206.338T+1487.429(T-Td)+

[0154] 1261.225lnT-426.51ln(T-Td)(1.13)

[0155] Level 2: T<23℃, V: 2.5~3m / s, T-Td: 1~1.5℃

[0156] y=3285.213+414.23(T-Td)(1.14)

[0157] Level 3: T<23℃, V: 2~2.5m / s, T-Td: 0.7~1℃

[0158] y=1549.856-202.5T+41.1833V+323.9697(T-Td)+

[0159] 4.078T 2 +866.226lnT-0.0525ln(T-Td)(1.15)

[0160] Level 4: T < 23 °C, V: 0 ~ 2 m / s, T-Td: 0 ~ 0.7 °C

[0161] y=99.65V+591.669(T-Td)-16.1V 2 -358.885(T-Td) 2 (1.16);

[0162] Among them, y is visibility, T is ground temperature, V is wind speed at 10m above ground, and Td is ground dew point temperature.

[0163] As a preferred embodiment of the present invention, specifically, using the forecast data of the mesoscale numerical model CMA_GD_3km, the forecast equation of wind shear is selected to calculate the wind shear, so as to perform the forecast correction of the high-altitude wind speed, including:

[0164] Based on the mesoscale numerical model CMA_GD_3km, determine whether there is a typhoon landing or severe convective weather during the forecast period. If there is no impact, the initial data of wind speed and wind shear are used;

[0165] If the forecast period is affected by severe convective weather, select equations (1.4) and (1.8) to calculate the lower-layer wind shear and upper-layer wind shear; if the forecast period is affected by a typhoon landing, select the corresponding equations (1.1-1.3) and (1.5-1.7) to calculate the lower-layer wind shear and upper-layer wind shear according to whether the typhoon lands on the eastern Guangdong coast, the central Guangdong coast, or the western Guangdong coast;

[0166] C3: The calculated lower and upper wind shears are used to correct the high-altitude wind speeds at 800m and 1500m using the ground 10m wind speed correction mode; the calculation relationship between the lower and upper wind shears and the corresponding layer wind speeds is as follows: WS 10m-800m +V 10m =V 800m (1.17)

[0167] WS 800m-1500m +V 800m =V 1500m (1.18);

[0168] Where WS is wind shear, V is wind speed, and the subscript represents a certain layer height or between two layers height, where 10m-800m represents the lower layer, and 800m-1500m represents the upper layer.

[0169] As a preferred embodiment of the present invention, specifically, determining whether there is a typhoon landing or severe convective weather during the forecast period includes:

[0170] Determine whether the echo reflectivity is greater than 50dBZ during the forecast period. If so, it means that there is a typhoon landing or severe convective weather.

[0171] As a preferred embodiment of the present invention, specifically, using the forecast data of the mesoscale numerical model CMA_GD_3km, the visibility forecast equation is selected to calculate the visibility, so as to perform the forecast correction of visibility, including:

[0172] Based on the mesoscale numerical model CMA_GD_3km, determine whether the initial visibility field needs to be corrected. If no correction is needed, the initial visibility data is used;

[0173] If correction is required, determine whether there is rain during the forecast period. When there is no rain, select equations (1.9~1.12) to calculate the corrected visibility. When there is rain, select equations (1.13~1.16) to calculate the corrected visibility.

[0174] Specifically, the present invention is used to evaluate the meteorological safety risks of rescue aircraft in low-altitude flights from March 12 to 14, 2020.

[0175] During the daytime from March 12 to 13, as the influence of cold air weakened in South China, water vapor increased rapidly, and the atmospheric saturation rose. Light fog or mist appeared in most parts of South China and coastal areas, and light rain fell in some places, forming a mixed weather of rain and fog. The visibility at many observation stations in Guangdong Province was less than 2000m or even less than 500m ( Figure 3 , Figure 3 The orange and red stations represent below 2km and 1km respectively, and the double horizontal lines, triple horizontal lines and dots represent light fog, mist and light rain).

[0176] Step A, using historical data to extract influencing factors through regression analysis method, calculate the effective weight coefficient of wind shear under the background of typhoon weather and severe convective weather, and calculate the effective weight coefficient of visibility at all levels when there is rain and when there is no rain.

[0177] Step B, establishing the forecast equations (1.1-1.16) of wind shear and visibility based on the effective weight coefficients obtained in step A.

[0178] Step C, using the ground 10m wind forecast data of the mesoscale numerical model CMA_GD_3km, select the wind shear forecast equation to calculate the wind shear, so as to make a forecast correction of the high-altitude wind speed.

[0179] Step D, using the visibility forecast data of the mesoscale numerical model CMA_GD_3km ( Figure 4 ), select the visibility forecast equation to calculate the visibility, and then make forecast corrections to the visibility.

[0180] Step E1: Using factors such as surface wind, high-altitude wind, wind shear, and visibility, and taking into account the severe convection and precipitation weather from March 12 to 14, define a low-altitude flight index (AFI) to comprehensively reflect whether the meteorological conditions are suitable for low-altitude flight and operations of rescue aircraft. The classification and description of the low-altitude flight index (AFI) are shown in Table 2.

[0181] Step E2: For the two types of rescue aircraft (S-67D rescue helicopter and rotary-wing UAV), design the classification range of ground wind, high-altitude wind, wind shear, and visibility meteorological elements, and combine them with the AFI index. The AFI classification of the two types of rescue aircraft and the classification combination of corresponding meteorological elements are shown in Tables 3 and 4.

[0182] Step F, using the calculated wind shear, corrected wind speed and calculated visibility and other meteorological factors to calculate and classify the low-altitude flight index ( Figure 5 ), complete the low-altitude flight meteorological safety risk assessment. The AFI of the corresponding rescue helicopters in the early morning of the 13th was between 50 and 60, which was at the third level with medium impact and high flight difficulty. In other areas, some AFIs reached the second level, indicating a slight impact and general flight difficulty; the AFI of the rotary-wing UAV exceeded 60, which was at the fourth level with severe impact. Since the UAV is remotely controlled by the rescue personnel, the actual field of view is narrower. Therefore, under the same visibility conditions, the control of the UAV is more difficult. At this time, the AFI reached the fourth level, indicating that the low visibility weather has seriously interfered with the flight and the risk is very high.

[0183] Starting from the afternoon of March 13, another cold front moved southward to affect southern China. This time, precipitation occurred near the front of the cold front, and the wind speed increased. Figure 6 It is a puzzle of radar echo combination reflectivity at 20:00 on the 13th. At this time, a large range of radar echoes appeared in central Guangdong, indicating that there was continuous precipitation in the area, and the visibility in the corresponding precipitation area decreased and the wind force increased. Figure 7 This is the radar echo at 20:00 on the 13th based on the GRAPES_GZ_3km model data. Figure 8This is the AFI forecast of the lower-level low-altitude flight index of the S-76D rescue helicopter at 20:00 on the 13th, which was obtained after correction based on the GRAPES_GZ_3km model data. It can be found that the forecast of the radar echo is consistent with the actual situation in terms of range, structure and intensity, and can basically reflect the location and magnitude of precipitation. The corresponding AFI of the rescue helicopter is between 30 and 80, spanning the 2nd to 4th level, showing a certain gradient range, indicating that the flight difficulties in the precipitation area also vary from general to severe, reflecting that the meteorological safety risks of low-altitude flights are affected by precipitation, visibility, wind and other factors at the same time, and the risks range from general to very high levels.

[0184] The present invention also proposes a device for assessing meteorological safety risks of a rescue aircraft during low-altitude flight, comprising the following:

[0185] A data acquisition module is used to acquire historical data of a target area, extract influencing factors from the historical data by regression analysis, and calculate effective weight coefficients of wind shear under the background of typhoon weather and severe convective weather, as well as effective weight coefficients of visibility at all levels when there is rain or no rain;

[0186] A forecast equation establishment module is used to establish a forecast equation for wind shear according to an effective weight coefficient of wind shear, and to establish a forecast equation for visibility according to effective weight coefficients of various levels of visibility;

[0187] The first forecast correction module is used to use the forecast data of the mesoscale numerical model CMA_GD_3km to select the wind shear forecast equation to calculate the wind shear, thereby correcting the forecast of the high-altitude wind speed;

[0188] The second forecast correction module is used to use the forecast data of the mesoscale numerical model CMA_GD_3km to select the visibility forecast equation to calculate the visibility, so as to make forecast corrections to the visibility;

[0189] A discrimination criterion definition module, used to define a low-altitude flight index AFI based on the influencing factors, and to classify and combine the AFI with preset meteorological elements to obtain a discrimination criterion;

[0190] The safety risk assessment module is used to calculate the low-altitude flight index based on the calculated wind shear, the forecast corrected high-altitude wind speed, and the forecast corrected visibility to obtain the calculation results, and complete the low-altitude flight meteorological safety risk assessment by comparing the calculation results with the judgment criteria.

[0191] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of software functional modules.

[0192] If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or system that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0193] Although the description of the present invention has been quite detailed and specifically describes several described embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, but should be regarded as providing a broad possible interpretation of these claims in view of the prior art by reference to the appended claims, thereby effectively covering the intended scope of the present invention. In addition, the above description of the present invention is based on the embodiments foreseeable by the inventor, and its purpose is to provide a useful description, and those non-substantial changes to the present invention that have not yet been foreseen may still represent equivalent changes to the present invention.

[0194] The above is only a preferred embodiment of the present invention. The present invention is not limited to the above implementation. As long as the technical effect of the present invention is achieved by the same means, it should belong to the protection scope of the present invention. Within the protection scope of the present invention, its technical scheme and / or implementation method can have various modifications and changes.

Claims

1. A method for assessing meteorological safety risks of rescue aircraft during low-altitude flight, characterized in that: Includes the following: Obtain historical data of the target area, extract influencing factors from the historical data through regression analysis method, and calculate effective weight coefficients of wind shear under the background of typhoon weather and severe convective weather, as well as effective weight coefficients of visibility at all levels when there is rain or no rain; The wind shear prediction equation is established according to the effective weight coefficient of wind shear, and the visibility prediction equation is established according to the effective weight coefficient of each level of visibility; Using the forecast data of the mesoscale numerical model CMA_GD_3km, the wind shear forecast equation is selected to calculate the wind shear, so as to make a forecast correction of the high-altitude wind speed; Using the forecast data of the mesoscale numerical model CMA_GD_3km, the visibility forecast equation is selected to calculate the visibility, so as to make a forecast correction of the visibility; Based on the influencing factors, a low-altitude flight index AFI is defined, and the AFI is graded and combined with preset meteorological elements to obtain a discrimination standard; The low-altitude flight index is calculated based on the calculated wind shear, forecast-corrected high-altitude wind speed, and forecast-corrected visibility, and the low-altitude flight meteorological safety risk assessment is completed by comparing the calculated result with the judgment standard.

2. The method for assessing meteorological safety risks of a rescue aircraft in low-altitude flight according to claim 1, characterized in that: Specifically, the wind shear prediction equation established includes: (1) Lower-level wind shear: from ground level to 800 meters Typhoon landfall affects the coastal areas of eastern Guangdong y=4.462+0.026x 2 -1.3×10 -7 e x (1.1) Typhoon landfall affects the coastal areas of central Guangdong y=6.089-0.4643x+3.385lnx(1.2) Typhoon landfall affects the coastal areas of western Guangdong y=3.555+0.041x 2 +3.516lnx(1.3) Severe convective weather y=6.639+0.0049x 2 +3×10 -6 and x (1.4) (2) Upper-level wind shear: ranges from 800m to 1500m Typhoon landfall affects the coastal areas of eastern Guangdong y=4.462+0.748x-0.022x 2 (1.5) Typhoon landfall affects the coastal areas of central Guangdong y=2.788+0.631x-1.2×10 -12 e x (1.6) Typhoon landfall affects the coastal areas of western Guangdong y=3.621+2.453x-5.684lnx+2×10 -7 e x (1.7) Severe convective weather y=5.321+0.126x 2 -1.657×10 -7 e x (1.8); Among them, x represents the wind speed 10m above the ground, and y represents the wind shear.

3. The method for assessing meteorological safety risks of a rescue aircraft in low-altitude flight according to claim 1, characterized in that: Specifically, the visibility prediction equation established includes: (1) When there is no rain Level 1: T<23℃, V<6m / s, T-Td: 1.5~2℃ y=6815.768+262.5165V-32.48V 2 -134.946lnV-138.127e (T-Td) (1.9) Level 2: T<23℃, V<6m / s, T-Td: 1~1.5℃ y=4027.295-81.8941T+2.0587T 2 (1.10) Level 3: T<23℃, V<6m / s, T-Td: 0.7~1℃ y=1318.762+1132.843(T-Td)+1.442T 2 - 572.87(T-Td) 2 +172.09e (T-Td) -170.134ln(T-Td)(1.11) Level 4: T<23℃, V<6m / s, T-Td: 0~0.7℃ y=1037.97(T-Td)+1.276×10 -8 e T - 1063.814(T-Td) 2 +407.651e (T-Td) -157.137ln(T-Td)(1.12) (2) When it rains Level 1: T<23℃, V: 3~6m / s, T-Td: 1.5~2℃ y=4385.699-206.338T+1487.429(T-Td)+ 1261.225lnT-426.51ln(T-Td)(1.13) Level 2: T<23℃, V: 2.5~3m / s, T-Td: 1~1.5℃ y=3285.213+414.23(T-Td)(1.14) Level 3: T<23℃, V: 2~2.5m / s, T-Td: 0.7~1℃ y=1549.856-202.5T+41.1833V+323.9697(T-Td)+ 4.078T 2 +866.226lnT-0.0525ln(T-Td)(1.15) Level 4: T < 23 °C, V: 0 ~ 2 m / s, T-Td: 0 ~ 0.7 °C y=99.65V+591.669(T-Td)-16.1V 2 -358.885(T-Td) 2 (1.16); Among them, y is visibility, T is ground temperature, V is wind speed at 10m above ground, and Td is ground dew point temperature.

4. The method for assessing meteorological safety risks of a rescue aircraft in low-altitude flight according to claim 2, characterized in that: Specifically, using the forecast data of the mesoscale numerical model CMA_GD_3km, the wind shear forecast equation is selected to calculate the wind shear, so as to make a forecast correction of the high-altitude wind speed, including: Based on the mesoscale numerical model CMA_GD_3km, determine whether there is a typhoon landing or severe convective weather during the forecast period. If there is no impact, the initial data of wind speed and wind shear are used; If the forecast period is affected by severe convective weather, select equations (1.4) and (1.8) to calculate the lower-layer wind shear and upper-layer wind shear; if the forecast period is affected by a typhoon landing, select the corresponding equations (1.1-1.3) and (1.5-1.7) to calculate the lower-layer wind shear and upper-layer wind shear according to whether the typhoon lands on the eastern Guangdong coast, the central Guangdong coast, or the western Guangdong coast; C3: The calculated lower and upper wind shears are used to correct the high-altitude wind speeds at 800m and 1500m using the ground 10m wind speed correction mode; the calculation relationship between the lower and upper wind shears and the corresponding layer wind speeds is as follows: WS 10m-800m +V 10m =V 800m (1.17) WS 800m-1500m +V 800m =V 1500m (1.18); Where WS is wind shear, V is wind speed, and the subscript represents a certain layer height or between two layers height, where 10m-800m represents the lower layer, and 800m-1500m represents the upper layer.

5. The method for assessing meteorological safety risks of a rescue aircraft in low-altitude flight according to claim 4, characterized in that: Specifically, determine whether there will be a typhoon landing or severe convective weather during the forecast period, including: Determine whether the echo reflectivity is greater than 50dBZ during the forecast period. If so, it means that there is a typhoon landing or severe convective weather.

6. The method for assessing meteorological safety risks of a rescue aircraft in low-altitude flight according to claim 3, characterized in that: Specifically, using the forecast data of the mesoscale numerical model CMA_GD_3km, the visibility forecast equation is selected to calculate the visibility, so as to make a forecast correction of visibility, including: Based on the mesoscale numerical model CMA_GD_3km, determine whether the initial visibility field needs to be corrected. If no correction is needed, the initial visibility data is used; If correction is required, determine whether there is rain during the forecast period. When there is no rain, select equations (1.9~1.12) to calculate the corrected visibility. When there is rain, select equations (1.13~1.16) to calculate the corrected visibility.

7. A device for assessing meteorological safety risks of rescue aircraft during low-altitude flight, characterized in that: Includes the following: A data acquisition module is used to acquire historical data of a target area, extract influencing factors from the historical data by regression analysis, and calculate effective weight coefficients of wind shear under the background of typhoon weather and severe convective weather, as well as effective weight coefficients of visibility at all levels when there is rain or no rain; A forecast equation establishment module is used to establish a forecast equation for wind shear according to an effective weight coefficient of wind shear, and to establish a forecast equation for visibility according to effective weight coefficients of various levels of visibility; The first forecast correction module is used to use the forecast data of the mesoscale numerical model CMA_GD_3km to select the wind shear forecast equation to calculate the wind shear, thereby correcting the forecast of the high-altitude wind speed; The second forecast correction module is used to use the forecast data of the mesoscale numerical model CMA_GD_3km to select the visibility forecast equation to calculate the visibility, so as to make forecast corrections to the visibility; A discrimination criterion definition module, used to define a low-altitude flight index AFI based on the influencing factors, and to classify and combine the AFI with preset meteorological elements to obtain a discrimination criterion; The safety risk assessment module is used to calculate the low-altitude flight index based on the calculated wind shear, the forecast corrected high-altitude wind speed, and the forecast corrected visibility to obtain the calculation results, and complete the low-altitude flight meteorological safety risk assessment by comparing the calculation results with the judgment criteria.

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