Height appointing method and system for wind guide of FY-4 cloud fused with cloud top air pressure

Abstract

The invention relates to the technical field of spaceflight meteorology, and particularly discloses a FY-4 cloud air guide height specifying method and system fusing cloud top air pressure, and the method comprises the steps: obtaining cloud top air pressure data and cloud air guide data of FY-4, and carrying out the matching of the cloud top air pressure data and the cloud air guide data according to a time difference and a spatial distance, obtaining a plurality of cloud top air pressure data in the tracking frame corresponding to the cloud air guide; retrieving the cloud top air pressure data in the tracking frame according to a spatial representative pixel searching method to obtain a target window with the strongest cloud top air pressure consistency in the tracking frame; combining the cloud top air pressure data in the target window according to a time representative pixel searching method to obtain a cloud top air pressure average value of two times; and determining a new cloud air guide height according to a difference value of the cloud top air pressure average values of the two times, and performing cloud air guide height assignment according to the new cloud air guide height.

Description

Technical Field

[0001] The present invention relates to the field of aerospace meteorology technology, and in particular to a method and system for specifying the altitude of a Fengyun-4 cloud guide wind integrated with cloud top pressure. Background Art

[0002] The global wind field is one of the important observation data for improving the initial conditions of numerical weather forecasts. In recent years, the global three-dimensional wind field detection data has become increasingly abundant. The satellite wind guidance products of the geostationary meteorological satellite imager can provide global high temporal and spatial resolution and wind field observations at different altitudes. They are still an important supplement to wind field observations in areas where conventional observations are insufficient, such as oceans and plateaus. Satellite wind guidance includes three types: infrared, water vapor and visible light wind guidance, with infrared channel clouds, water vapor targets and visible light channel clouds as tracers respectively. The deviations mainly come from target tracking and altitude designation, of which the altitude designation error accounts for 70%.

[0003] Taking the infrared channel wind guidance as an example, the former is because various types of clouds moving at different speeds are detected in the target tracking frame, which makes it difficult to select the tracer, and the latter is due to the complex conditions such as translucent / transparent clouds and multi-layer clouds that are widely present in the atmosphere, which reduces the accuracy of altitude designation.

[0004] Therefore, reducing satellite wind guidance errors is an important means to increase the amount of data assimilated in the numerical forecast system and enhance its contribution to the improvement of the initial field. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method and system for specifying the altitude of FY-4 cloud guide wind that integrates cloud top pressure, which integrates cloud top pressure data with more accurate cloud top pressure estimation and higher temporal and spatial resolution, improves the connection between geostationary satellite products, and provides a new idea for the multi-source data fusion method in the cloud guide wind deviation correction process. The cloud guide wind after altitude re-specification can play a more beneficial role in the wind field forecast of the numerical model.

[0006] The present invention provides a method for specifying the height of a FY-4 cloud guide wind integrated with cloud top pressure, comprising:

[0007] Step S1, obtaining cloud top pressure data and cloud guide wind data of FY-4, matching the cloud top pressure data and cloud guide wind data according to time difference and spatial distance, and obtaining a plurality of cloud top pressure data in a tracking frame corresponding to the cloud guide wind; the cloud top pressure data includes cloud top pressure data;

[0008] Step S2, searching the cloud top pressure data in the tracking frame according to a spatial representative pixel search method to obtain a target window with the strongest consistency of cloud top pressure in the tracking frame; the spatial representative pixel search method is obtained according to a nested tracking algorithm of an advanced baseline imager cloud wind guide product;

[0009] Step S3, merging the cloud top pressure data in the target window according to a time representative pixel search method to obtain an average value of the cloud top pressure at two times; the time representative pixel search method is obtained according to a cloud wind guide algorithm;

[0010] Step S4, determining a new cloud wind guide height according to the difference between the average values ​​of the cloud top pressures at the two times, and specifying the cloud wind guide height according to the new cloud wind guide height.

[0011] In a possible implementation, the cloud top pressure data and the cloud guide wind data include time resolution; and S1 includes:

[0012] Acquire the cloud guide wind data at a first time, and two second times with a time resolution of one from the first time;

[0013] The cloud top pressure data corresponding to the second time is matched with the cloud guide wind data of the first time.

[0014] In a possible implementation, the cloud wind guide data includes cloud top pressure data; and S1 further includes:

[0015] The spatial position corresponding to the cloud wind guide is searched according to the row and column number information in the cloud wind guide data, and the spatial position is represented by the tracking frame.

[0016] In a possible implementation, the S2 includes:

[0017] Get a window representing a motion tracer;

[0018] The window is used to traverse the tracking frame, the consistency of the cloud top pressure in each window is calculated, and the window with the strongest cloud top pressure consistency is used as the target window.

[0019] In a possible implementation, the S2 further includes:

[0020] The cloud top pressure consistency W within the window is calculated according to the following formula:

[0021]

[0022] In the formula, argmin means taking the smallest parameter value of the following expression, n means the number of cloud top pressure data in the window, P ci represents the ith cloud top pressure data, and μ represents the average value of the cloud top pressure data in the window.

[0023] In a possible implementation, the size of the window is the minimum second-order moment of the cloud top pressure.

[0024] In a possible implementation, the S4 includes:

[0025] Determine the cloud wind deflector height according to the following formula

[0026]

[0027] In the formula, and They are respectively the average values ​​of cloud top pressure data at two times after searching for spatially representative pixels.

[0028] In a possible implementation, the method further includes:

[0029] Conducting an effectiveness test on the new cloud wind guide height;

[0030] When the effect test fails to meet the standards, the cloud guide wind height is re-assigned based on the cloud top pressure data, cloud guide wind data and ERA5 global reanalysis data.

[0031] In a possible implementation, the checking the effect of the new cloud wind guide height includes:

[0032] By comparing and analyzing the deviation distribution of the cloud guide wind data corresponding to the original cloud guide wind height and the new cloud guide wind height, the effect of the new cloud guide wind height is tested.

[0033] The present invention also provides a height designation system for the FY-4 cloud guide wind that integrates the cloud top pressure, and applies any of the above-mentioned height designation methods, including:

[0034] A matching module is used to obtain the cloud top pressure data and cloud guide wind data of Fengyun-4, match the cloud top pressure data and cloud guide wind data according to the time difference and spatial distance, and obtain multiple cloud top pressure data in the tracking frame corresponding to the cloud guide wind; the cloud top pressure data includes cloud top pressure data;

[0035] A target window search module is used to retrieve the cloud top pressure data in the tracking frame according to a spatial representative pixel search method to obtain a target window with the strongest consistency of cloud top pressure in the tracking frame; the spatial representative pixel search method is obtained according to a nested tracking algorithm of an advanced baseline imager cloud wind guide product;

[0036] A representative pixel search module is used to merge the cloud top pressure data in the target window according to a temporal representative pixel search method to obtain an average value of the cloud top pressure at two times; the temporal representative pixel search method is obtained according to a cloud wind guide algorithm;

[0037] The determination module is used to determine a new cloud wind guide height according to the difference between the average values ​​of the cloud top pressure at the two times, and to designate the cloud wind guide height according to the new cloud wind guide height.

[0038] The method and system for specifying the height of the FY-4A cloud guide wind integrated with the cloud top pressure provided by the present invention utilizes the FY-4A cloud top pressure product with the added carbon dioxide slice channel algorithm to re-specify the height of the cloud guide wind, and combines the spatial representative pixel search and temporal representative pixel search of the tracer within the tracking frame range, so as to further improve the wind field forecast of the numerical weather forecast model;

[0039] The present invention first matches the cloud guide wind with the cloud top pressure data of the continuous observation time, obtains the small window in the tracking frame by the spatial representative pixel search method, and calculates the cloud top pressure in the small window respectively; then, the two time "small window" samples generated in each target scene are merged by the temporal representative pixel search method to obtain the target height for height re-assignment;

[0040] The present invention integrates cloud top pressure data with more accurate cloud top pressure estimation and higher temporal and spatial resolution, improves the connection between geostationary satellite products, and provides a new idea for the multi-source data fusion method in the cloud guide wind deviation correction process. The cloud guide wind after height re-designation can play a more beneficial role in the wind field forecast of the numerical model.

[0041] The present invention uses the cloud top pressure data provided by Fengyun-4, avoiding the problems of different full disk ranges of different satellite data and difficulty in matching data. It has the advantages of simple calculation steps, efficient correction method, convenient data fusion, easy implementation and understanding, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a flow chart of a height specification method provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of a tracking frame provided by an embodiment of the present invention;

[0044] Figure 3 A time variation characteristic diagram of the deviation and root mean square error before and after the height re-assignment provided by an embodiment of the present invention;

[0045] Figure 4 A time variation characteristic diagram of the mean square error of the infrared channel vector before and after the altitude reassignment provided by an embodiment of the present invention;

[0046] Figure 5 A distribution diagram of the total number of cloud guide winds in the infrared channel with latitude before and after the altitude re-assignment provided by an embodiment of the present invention;

[0047] Figure 6A schematic diagram of the distribution of the number of instruments provided in the embodiment of the present invention;

[0048] Figure 7 A schematic diagram of the U wind speed deviation distribution of the cloud-guided wind provided in an embodiment of the present invention;

[0049] Figure 8 A schematic diagram of the change of the U wind speed deviation of the FY4A cloud guide wind before and after the height reassignment in the observation space after the four-dimensional variational assimilation provided by the embodiment of the present invention with time;

[0050] Fig. 9 A first root mean square error comparison diagram provided in an embodiment of the present invention;

[0051] Fig.10 A second root mean square error comparison diagram provided by an embodiment of the present invention;

[0052] Fig.11 A third root mean square error comparison diagram provided in an embodiment of the present invention;

[0053] Fig.12 A fourth root mean square error comparison schematic diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The following detailed description of the embodiments of the present invention is further described in detail in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the preferred embodiments described, and the scope of the present invention is defined by the claims.

[0055] In the description of the present invention, it should be noted that, unless otherwise specified, “plurality” means two or more than two; the terms “first”, “second”, etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0056] Figure 1 A flow chart of a method for specifying a height provided in an embodiment of the present invention is shown in FIG. Figure 1 As shown, the present invention provides a method for specifying the height of the FY-4 cloud guide wind integrating the cloud top pressure, comprising:

[0057] Step S1, obtaining the cloud top pressure data and cloud guide wind data of FY-4, matching the cloud top pressure data and cloud guide wind data according to time difference and spatial distance, and obtaining multiple cloud top pressure data in the tracking frame corresponding to the cloud guide wind;

[0058] In a possible implementation, the cloud top pressure data and cloud guide wind data include temporal resolution and spatial resolution; the cloud top pressure data mainly include radial component, latitudinal component and cloud top pressure data, wherein the cloud top pressure is used to indicate the height level where the wind field is located.

[0059] Obtain cloud guide wind data at the first time, and two second times with a time resolution of one from the first time;

[0060] Match the cloud top pressure data corresponding to the second time with the cloud guide wind data at the first time.

[0061] In a possible implementation, the spatial position corresponding to the cloud guide wind is searched according to the row and column number information in the cloud guide wind data, and the spatial position is represented by a tracking frame.

[0062] In one example, the L2 infrared channel cloud guide wind data of FY-4A / AGRI is used to match the L2 cloud top pressure data of FY-4A / AGRI at the corresponding time to obtain the cloud top pressure data in each tracking frame. The time resolution of the cloud guide wind data is 3h and the spatial resolution is 48km. The time resolution of the cloud top pressure data is about 15min and the spatial resolution is 4km; therefore, each hourly cloud guide wind data is matched with two cloud top pressure observation data within 15min before and after. For example, for the cloud guide wind data at 06:00 on July 1, 2022, the cloud top pressure data observed twice at 05:45:00-05:59:59 and 06:00:00-06:14:59 are selected.

[0063] In one possible implementation, channel 12 of the cloud-guided wind data has a central band of 10.8 μm, a time resolution of 3 hours, and a spatial resolution of 48 km. The cloud top pressure data algorithm mainly uses a one-dimensional variational method using channels 12-14, with a time resolution of about 15 minutes and a spatial resolution of 4 km.

[0064] When selecting cloud guide wind data, firstly, the satellite data of different seasons are temporally and spatially matched, including four representative months, July (summer) and October (autumn) in 2022, January (winter) and April (spring) in 2023. Select cloud guide wind data with higher quality, that is, the quality control parameter QI (Quality Indicator) is greater than 85 (Liang et al, 2021), the selected cloud guide wind is 4 times a day (00, 06, 12, 18, UTC), select the cloud top pressure products corresponding to the two times before and after the generation of cloud guide wind, and select the cloud top pressure data within the 12*12 pixel frame around the center point of the cloud guide wind.

[0065] Step S2, searching the cloud top pressure data in the tracking frame according to the spatial representative pixel search method, and obtaining the target window with the strongest consistency of cloud top pressure in the tracking frame;

[0066] Among them, the spatial representative pixel search method is obtained according to the nested tracking algorithm of the advanced baseline imager cloud wind product, which is used to obtain the range representing the moving tracer in the tracking frame.

[0067] In a possible implementation, the range of the window nested in the tracking frame is not fixed, and the size of the window is the minimum second-order moment of the cloud top pressure, which can be a window of 3*3, 5*5, 7*7, or 9*9 pixels.

[0068] Figure 2 A schematic diagram of a tracking frame provided by an embodiment of the present invention, such as Figure 2 As shown, the larger outer box is the tracking box, the smaller inner solid box is the window, and the smaller dotted box is the schematic diagram after the window moves.

[0069] In one possible implementation, a window representing a motion tracer is obtained; the window is used to traverse the tracking frame, the consistency of the cloud top pressure in each window is calculated, and the window with the strongest consistency of the cloud top pressure is used as the target window.

[0070] In a possible implementation, S2 further includes:

[0071] The cloud top pressure consistency W within the window is calculated according to the following formula:

[0072]

[0073] In the formula, argmin means taking the smallest parameter value of the following expression, n means the number of cloud top pressure data in the window, P ci represents the ith cloud top pressure data, and μ represents the average value of the cloud top pressure data in the window.

[0074] Step S3, merging the cloud top pressure data in the target window according to the temporal representative pixel search method to obtain the average cloud top pressure of two time periods;

[0075] Among them, the temporal representative pixel search method is obtained based on the cloud-wind algorithm.

[0076] Step S4, determining a new cloud wind guide height according to the difference between the average values ​​of the cloud top pressure at two times, and designating the cloud wind guide height according to the new cloud wind guide height.

[0077] In a possible implementation, S4 includes:

[0078] Determine the cloud wind deflector height according to the following formula

[0079]

[0080] In the formula, and are respectively the average values (hPa) of the cloud top pressure data at two times after the spatial representative pixel search.

[0081] In a possible implementation manner, it further includes:

[0082] Conduct an effect test on the new cloud-derived wind height;

[0083] When the effect test fails to meet the standard, re-specify the cloud-derived wind height according to the cloud top pressure data, cloud-derived wind data, and ERA5 global reanalysis data.

[0084] The ERA5 global reanalysis data is used as the reference field for the research, and the deviation distribution of the cloud-derived wind data before and after the height re-specification is analyzed by comparison. Its time resolution is 1 hour, and the spatial resolution is 0.25°.

[0085] In a possible implementation manner, conducting an effect test on the new cloud-derived wind height includes:

[0086] Conduct an effect test on the new cloud-derived wind height by comparing and analyzing the deviation distribution of the cloud-derived wind data corresponding to the original cloud-derived wind height and the new cloud-derived wind height.

[0087] The present invention will be further described below in conjunction with specific embodiments.

[0088] I. The re-specification of the cloud-derived wind height has an improvement effect on the cloud-derived wind accuracy

[0089] Figure 3 are the time variation characteristics of the deviation and root mean square error of the U component of the cloud-derived wind in the high (P < 400 hPa), medium (400 hPa < P < 700 hPa), and low (700 hPa < P < 1000 hPa) layers of the FY-4A infrared channel cloud-derived wind before and after the height re-specification in different seasons. Among them, (a) Summer: July 2022, (b) Autumn: October 2022, (c) Winter: January 2023, (d) Spring: April 2023. As Figure 3 shown, the average deviation in the high layer (pressure greater than 400 hPa) in spring (April 2023) decreases most significantly, from -0.44 to -0.02 m / s; the root mean square error in the middle layer (pressure greater than or equal to 400 hPa and less than 700 hPa) in autumn (October 2022) is the smallest after the height re-specification, which is 3.57 m / s (see Figure 3 b); the average deviation in the low layer (pressure greater than or equal to 700 hPa) in autumn (October 2022) decreases most significantly, from -0.76 to 0.23 m / s (see Figure 3b). The difference between the maximum and minimum values ​​of the root mean square error decreased from 1.95m·s-1 to 0.88m·s-1, and the long-term consistency of the data was improved.

[0090] Figure 4 The time variation characteristics of the vector mean square error (VMSE) of the FY-4A infrared channel before and after the altitude reassignment. Figure 4 As shown in the figure, the vector mean square error (VMSE) of the high, medium and low layers has been significantly reduced. The average vector mean square error of the four representative months in the high layer ranged from 4.30m·s-1 to 3.55m·s-1, in the middle layer from 4.58m·s-1 to 3.79m·s-1, and in the low layer from 2.75m·s-1 to 2.46m·s-1. The improvement effect of the vector wind speed deviation in the low layer is slightly lower than that in the medium and high layers.

[0091] By comparing the results of different seasons, it can be found that the height re-assignment effect of the middle and high layers in spring (April 2023) and autumn (October 2022) is the best. This is related to the higher frequency of cirrus clouds in spring and autumn and their greater optical thickness, indicating that the CO2 slicing method has a significant effect on improving the height of cirrus clouds.

[0092] Table 1 is a statistical table of the cloud wind guide test results before and after height reassignment. As shown in Table 1, the average root mean square error of the four representative months in the high layer decreased most significantly from 4.06m·s-1 to 3.25m·s-1, the middle layer decreased from 4.25m·s-1 to 3.71m·s-1, and the low layer decreased from 2.42m·s-1 to 2.13m·s-1. In addition, the average absolute percentage error of each layer decreased, and the improvement was most obvious in the middle layer from 18.88% to 16.83%.

[0093] Table 1

[0094]

[0095]

[0096] 2. Analysis of the Improved Effect of Reassignment of Cloud Wind Guide Height

[0097] Figure 5 The total number of FY-4A infrared channel cloud guide winds with latitude distribution before and after the altitude reassignment in July 2022, including (a) low layer, (b) middle layer, and (c) high layer. After the altitude reassignment, the number of low-level cloud guide winds at each latitude increased, the number of high-level cloud guide winds decreased, the number of middle-level cloud guide winds in the southern hemisphere decreased, and the number of cloud guide winds in the northern hemisphere increased (see Figure 5 ). In July 2022, the number of low-level cloud guide winds in the Southern Hemisphere was significantly higher than that in the Northern Hemisphere. This phenomenon may be due to the fact that the Southern Hemisphere is in winter in July, which makes it easier for low clouds to form. Overall, after the height is reassigned, the number of low-level cloud guide winds increased by 50.99%, while the number of mid- and high-level cloud guide winds decreased by 0.76% and 20.56%, respectively.

[0098] Table 2 describes the deviation and root mean square error of cloud guide wind in the same layer before and after height reassignment. The cloud guide wind samples that were always in the same layer before and after height reassignment in July 2022 were counted, and it was found that the deviation and root mean square error were also reduced. The average number of samples that were always in the same layer at low altitude was 1197 (accounting for 95.53% before reassignment and 63.23% after reassignment), the average number of samples at middle altitude was 699 (accounting for 59.03% before reassignment and 58.59% after reassignment), and the average number of samples at high altitude was 2527 (accounting for 77.11% before reassignment and 97.08% after reassignment). This result shows that the improvement of cloud guide wind deviation and root mean square error in 2.1 is not caused by the overall height reduction (i.e., the reduction of wind speed in the inspection background field), but is the effect of the improvement of cloud top pressure assignment accuracy.

[0099] Table 2

[0100]

[0101] Table 3 shows the experimental design of the CMA-GFS numerical forecast model. In order to analyze the improvement of the FY4A cloud guide wind on the numerical weather forecast model forecast after height reassignment, three groups of control experiments were designed as shown in Table 3. The model adopts CMA-GFS4.2, the background field uses GFS with a time resolution of 3 hours, the observation data are conventional business data plus satellite data, and the data assimilation period is from July 22, 2022 to August 22, 2022.

[0102] Table 3

[0103] Test Name The observation error used Assimilated cloud wind data No default value General AMV information FY4A AMV default value Added FY-4A IR cloud wind guide FY4A CTP+AMV default value Added altitude re-designation after FY-4A IR cloud guide

[0104] In the CMA-GFS mode preprocessing module, add the processing module for reading and writing FY-4A cloud guide wind, write the AMV data corresponding to the FY4A satellite into the R2CWE file, and generate the SATOB file containing the FY4A AMV. Figure 6 The distribution of the number of AMVs of each satellite instrument in the SATOB file after writing the FY4A cloud guide wind.

[0105] The analysis of the improvement effect of FY4A cloud wind guide in the observation space after assimilation is as follows.

[0106] After data assimilation by the CMA-GFS model, each data in each group of experimental observation space was tested to see the improvement effect of the FY4A cloud guide wind model after the assimilation height was re-specified. Figure 7Figure 2 shows the U wind speed deviation distribution of FY4A cloud guide wind before and after height reassignment in the observation space after 4D variational assimilation (background field minus observation field). Before height reassignment, the directly assimilated FY4A cloud guide wind has obvious positive deviations in the upper layers (150-350hPa) of the southern hemisphere (25-60°S), and in the equatorial region (10°S-25°N). There are negative deviations in the middle and lower layers of the northern hemisphere, and positive deviations in the upper layers. The magnitude of these deviations has been significantly improved after height reassignment (from 5m / s to 2m / s).

[0107] Figure 8 is the wind speed deviation of FY4A cloud guide wind before and after height reassignment in the observation space after four-dimensional variational assimilation (background field minus observation field), such as Figure 8 As shown in the figure, the long-term consistency of FY4A cloud wind deviation at each time in the observation space after data assimilation has been improved, among which the consistency of 100-200hPa cloud wind deviation has been improved most significantly, and the average deviation of cloud wind at each altitude has been reduced.

[0108] Fig. 9 The root mean square error comparison diagram of the numerical model results h before and after height reassignment at different heights in different areas is shown in the figure below. Fig. 9 As shown in the figure, the h of the FY4A cloud guide wind and the model output before and after the assimilation height reassignment are compared. The RMSE of each layer in East Asia has improved significantly, there has been improvement in the middle and low layers in the Southern Hemisphere, the RMSE of the high layers has increased, and there has been improvement in the high layers in the Northern Hemisphere.

[0109] Fig.10 The root mean square error comparison diagram of the numerical model results q before and after height reassignment at different heights in different areas is shown in the figure below. Fig.10 As shown in Figure 2, the q comparison of the model output shows that the mid-level RMSE in the Northern Hemisphere and East Asia has been significantly improved.

[0110] Fig.11 Comparison chart of the root mean square error of the numerical model results u before and after height reassignment at different altitudes in different regions. Fig.12 The root mean square error comparison diagram of the numerical model results v before and after height reassignment at different heights in different areas is shown in the figure below. Fig.11 and Fig.12 As shown in the figure, after the height is reassigned, the RMSE improvement of the u and v components in each layer in the southern hemisphere is better than that in the northern hemisphere, and there is a significant improvement in the u and v components in the middle layer in the northern hemisphere and East Asia.

[0111] The present invention uses the cloud top pressure product with the CO2 slice channel algorithm to re-assign the cloud guide wind height, and uses data matching, adaptive nested search, time consistency check, height re-assignment and other steps to fuse the cloud guide wind data with the cloud top pressure data. The method is simple, efficient and easy to implement, and has a good effect on improving the FY4A cloud guide wind deviation caused by height assignment. The following are some advantages of this method:

[0112] Efficiency: Since only the same satellite L2 level products are used to specify the cloud guide wind height in a data fusion manner, it has advantages in data space and time matching, and the time complexity is constant. This method is very fast in execution speed. This is crucial in applications that require fast response.

[0113] Predictability: Since the time complexity is fixed, you can accurately predict the performance and response time of the program regardless of the size of the input.

[0114] Save resources: Satellite L2 products do not require large amounts of memory or data structures to store data, which helps save memory and resources, especially for embedded systems or resource-constrained environments.

[0115] Simplicity: The inversion algorithm has not been modified, so the height reassignment method is relatively simple, easy to understand and maintain. This can reduce the complexity of the code and reduce the possibility of errors.

[0116] Applicability: The altitude reassignment method is applicable to other satellite cloud wind altitude assignment problems. For satellite cloud wind products that still use traditional altitude determination methods, this method can be tried for altitude reassignment.

[0117] The present invention also provides a height designation system for the FY-4 cloud guide wind that integrates the cloud top pressure, and applies any of the above-mentioned height designation methods, including:

[0118] The matching module is used to obtain the cloud top pressure data and cloud guide wind data of Fengyun-4, match the cloud top pressure data and cloud guide wind data according to the time difference and spatial distance, and obtain multiple cloud top pressure data in the tracking frame corresponding to the cloud guide wind; the cloud top pressure data includes cloud top pressure data;

[0119] The target window search module is used to retrieve the cloud top pressure data in the tracking frame according to the spatial representative pixel search method to obtain the target window with the strongest consistency of cloud top pressure in the tracking frame; the spatial representative pixel search method is obtained according to the nested tracking algorithm of the cloud wind guide product of the Advanced Baseline Imager;

[0120] The representative pixel search module is used to merge the cloud top pressure data in the target window according to the temporal representative pixel search method to obtain the average value of the cloud top pressure at two times; the temporal representative pixel search method is obtained according to the cloud guide wind algorithm;

[0121] The determination module is used to determine a new cloud guide wind height according to the difference between the average values ​​of the cloud top pressure at two times, and to designate the cloud guide wind height according to the new cloud guide wind height.

[0122] The method and system for specifying the height of the FY-4A cloud guide wind integrated with the cloud top pressure provided by the present invention utilizes the FY-4A cloud top pressure product with the added carbon dioxide slice channel algorithm to re-specify the height of the cloud guide wind, and combines the spatial representative pixel search and temporal representative pixel search of the tracer within the tracking frame range, so as to further improve the wind field forecast of the numerical weather forecast model;

[0123] The present invention first matches the cloud guide wind with the cloud top pressure data of the continuous observation time, obtains the small window in the tracking frame by the spatial representative pixel search method, and calculates the cloud top pressure in the small window respectively; then, the two time "small window" samples generated in each target scene are merged by the temporal representative pixel search method to obtain the target height for height re-assignment;

[0124] The present invention integrates cloud top pressure data with more accurate cloud top pressure estimation and higher temporal and spatial resolution, improves the connection between geostationary satellite products, and provides a new idea for the multi-source data fusion method in the cloud guide wind deviation correction process. The cloud guide wind after height re-designation can play a more beneficial role in the wind field forecast of the numerical model.

[0125] The present invention uses the cloud top pressure data provided by Fengyun-4, avoiding the problems of different full disk ranges of different satellite data and difficulty in matching data. It has the advantages of simple calculation steps, efficient correction method, convenient data fusion, easy implementation and understanding, etc.

[0126] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which 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 specifying the height of the FY-4 cloud guide wind by integrating the cloud top pressure, characterized in that: include: Step S1, obtaining cloud top pressure data and cloud guide wind data of FY-4, matching the cloud top pressure data and cloud guide wind data according to time difference and spatial distance, and obtaining a plurality of cloud top pressure data in a tracking frame corresponding to the cloud guide wind; the cloud top pressure data includes cloud top pressure data; Step S2, searching the cloud top pressure data in the tracking frame according to a spatial representative pixel search method to obtain a target window with the strongest consistency of cloud top pressure in the tracking frame; the spatial representative pixel search method is obtained according to a nested tracking algorithm of an advanced baseline imager cloud wind guide product; Step S3, merging the cloud top pressure data in the target window according to a time representative pixel search method to obtain an average value of the cloud top pressure at two times; the time representative pixel search method is obtained according to a cloud wind guide algorithm; Step S4, determining a new cloud wind guide height according to the difference between the average values ​​of the cloud top pressures at the two times, and specifying the cloud wind guide height according to the new cloud wind guide height.

2. The height specifying method according to claim 1, characterized in that: The cloud top pressure data and the cloud wind guide data include time resolution; S1 includes: Acquire the cloud guide wind data at a first time, and two second times with a time resolution of one from the first time; The cloud top pressure data corresponding to the second time is matched with the cloud guide wind data of the first time.

3. The height specifying method according to claim 2, characterized in that: The cloud wind guide data includes cloud top pressure data; S1 also includes: The spatial position corresponding to the cloud wind guide is searched according to the row and column number information in the cloud wind guide data, and the spatial position is represented by the tracking frame.

4. The height specifying method according to claim 1, characterized in that: The S2 includes: Get a window representing a motion tracer; The window is used to traverse the tracking frame, the consistency of the cloud top pressure in each window is calculated, and the window with the strongest cloud top pressure consistency is used as the target window.

5. The height specifying method according to claim 4, characterized in that: The S2 further includes: The cloud top pressure consistency W within the window is calculated according to the following formula: In the formula, argmin means taking the smallest parameter value of the following expression, n means the number of cloud top pressure data in the window, P ci represents the ith cloud top pressure data, and μ represents the average value of the cloud top pressure data in the window.

6. The height specifying method according to claim 4, characterized in that: The size of the window is the minimum second moment of the cloud top pressure.

7. The height specifying method according to claim 1, characterized in that: The S4 includes: Determine the cloud wind deflector height according to the following formula In the formula, and They are respectively the average values ​​of cloud top pressure data at two times after searching for spatially representative pixels.

8. The height specifying method according to claim 1, characterized in that: Also includes: Conducting an effectiveness test on the new cloud wind guide height; When the effect test fails to meet the standards, the cloud guide wind height is re-assigned based on the cloud top pressure data, cloud guide wind data and ERA5 global reanalysis data.

9. The height specifying method according to claim 8, characterized in that: The effect test of the new cloud wind guide height comprises: By comparing and analyzing the deviation distribution of cloud guide wind data corresponding to the original cloud guide wind height and the new cloud guide wind height, the effect of the new cloud guide wind height is tested.

10. A FY-4 cloud wind guide altitude designation system integrating cloud top pressure, characterized in that: The method for specifying the height according to any one of claims 1 to 9 is applied, comprising: A matching module is used to obtain the cloud top pressure data and cloud guide wind data of Fengyun-4, match the cloud top pressure data and cloud guide wind data according to the time difference and spatial distance, and obtain multiple cloud top pressure data in the tracking frame corresponding to the cloud guide wind; the cloud top pressure data includes cloud top pressure data; A target window search module is used to retrieve the cloud top pressure data in the tracking frame according to a spatial representative pixel search method to obtain a target window with the strongest consistency of cloud top pressure in the tracking frame; the spatial representative pixel search method is obtained according to a nested tracking algorithm of an advanced baseline imager cloud wind guide product; A representative pixel search module is used to merge the cloud top pressure data in the target window according to a temporal representative pixel search method to obtain an average value of the cloud top pressure at two times; the temporal representative pixel search method is obtained according to a cloud wind guide algorithm; The determination module is used to determine a new cloud wind guide height according to the difference between the average values ​​of the cloud top pressure at the two times, and to designate the cloud wind guide height according to the new cloud wind guide height.

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