A cloud amount calculation method and device based on a millimeter wave cloud detector

Abstract

The present invention relates to a cloud amount calculation method and device based on a millimeter wave cloud detector, belonging to the field of radio. The calculation method includes: cyclically inputting radar data, reading the latest radar base data, and removing clutter according to a reflectivity threshold; dividing different cloud layers according to the continuity of reflectivity, and respectively calculating the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer of cloud in the radial direction; performing cloud amount calculation and cloud amount calculation for each radial direction through the cloud base height, cloud layer thickness, and reflectivity weighted value; multiplying the time corresponding to each radial direction by different weights to obtain the cloud amount at the current moment and outputting the result, and sending the cumulative cloud amount into the cycle to continuously obtain real-time cloud amount data. The present invention improves the reliability of data and lays a good foundation for the subsequent observation and processing of data. Accurately calculating the cloud amount helps to improve the accuracy of weather forecasting.

Description

Technical Field

[0001] The present invention relates to the field of radio, and in particular to a cloud amount calculation method and device based on a millimeter wave cloud detector. Background Art

[0002] Cloud amount refers to the percentage of the sky view obscured by clouds, and is one of the important indicators characterizing weather and climate characteristics. It reflects the process of water vapor condensation and cloud formation in the atmosphere, and has a direct impact on weather phenomena such as atmospheric radiation, temperature change, and precipitation. With its high time and space resolution, strong penetration ability, and continuous monitoring ability, the millimeter wave cloud detector can clearly describe the internal physical structure of clouds and has become an important tool in meteorological research and cloud physics observation. However, the field of view of the millimeter wave cloud detector is small, and the measurement accuracy is low only by the cloud detector. Therefore, how to calculate the cloud amount through the millimeter wave cloud detector is a problem that needs to be considered at present. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art, and provides a cloud amount calculation method and device based on a millimeter wave cloud detector, which solves the deficiencies existing in the prior art.

[0004] The purpose of the present invention is achieved through the following technical solutions: A cloud amount calculation method based on a millimeter wave cloud detector, the calculation method includes:

[0005] S1. Circularly input radar data, read the latest radar base data, and remove clutter according to the reflectivity threshold;

[0006] S2. Segment different cloud layers according to the continuity of the reflectivity, and respectively calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer of cloud in the radial direction;

[0007] S3. Perform cloud amount calculation and calculation of cloud amount in each radial direction through the cloud base height, cloud layer thickness, and reflectivity weighted value;

[0008] S4. Multiply the time corresponding to each radial direction by different weights to obtain the cloud amount at the current moment and output the result, and send the cumulative cloud amount into the loop to continuously obtain real-time cloud amount data.

[0009] The S2 includes:

[0010] In the radial direction, if there is a region where the reflectivity has values in more than N range bins, and the proportion of the range bins with non-zero reflectivity in this region exceeds the set value, then this region with continuous non-zero reflectivity is a cloud layer, and there are at least N range bins with no values between cloud layers;

[0011] After cloud layer segmentation, calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer respectively. Among them, the cloud base height is the number of range bins with a valid reflectivity in the first layer of cloud multiplied by the range resolution, the cloud layer thickness is the number of range bins occupied between the first range bin with a valid reflectivity and the last range bin with a valid reflectivity in this layer of cloud multiplied by the range resolution, and the reflectivity weighted value is the sum of the average reflectivity of this layer of cloud and the reflectivity threshold divided by 15.

[0012] The cloud amount calculation in S3 includes:

[0013] According to the different cloud base heights, different coefficients are used to calculate the cloud amount. If the cloud base height is less than 0.5 km and the cloud layer thickness exceeds 0.6 km, it is considered that rain is about to fall or is falling, and it is in a full cloud state, and the cloud amount is the maximum value;

[0014] In other cases, the cloud amount is equal to the coefficient multiplied by the cloud layer thickness multiplied by the reflectivity weighted value. If the cloud base height is less than 2.5 km, it is considered that this layer is a low cloud, and the coefficient is 40. If the cloud base height is greater than 2.5 km and less than 8.5 km, it is considered that this layer of cloud is a middle cloud, and the coefficient is 35. If the cloud base height is greater than 8.5 km, it is considered that this layer of cloud is a high cloud, and the coefficient is 25.

[0015] The calculation of the cloud amount in each radial direction in S3 includes:

[0016] According to the sum of the cloud amounts of each layer in the obtained radial direction, the cloud amount in the radial direction is obtained. The maximum value of the cloud amount in each radial direction is set to 150. If the cloud amount in the last radial direction is greater than 100, the part exceeding 100 is accumulated into the cloud amount cumulative value. If the cloud amount in the last radial direction is less than 100 and the cloud amount cumulative value is greater than 0, the cloud amount cumulative value is used to fill the last radial direction, and the maximum filling is up to 100. If the cloud amount in the last radial direction is less than 100 and the cloud amount cumulative value is less than 0, no processing is performed.

[0017] A cloud amount calculation device based on a millimeter-wave cloud detector, the device includes a data preprocessing module, a cloud layer segmentation and calculation module, a cloud amount calculation module, and a real-time cloud amount acquisition module;

[0018] The data preprocessing module is configured to cyclically input radar data, read the latest radar base data, and remove clutter according to the reflectivity threshold;

[0019] The cloud layer segmentation and calculation module is configured to segment different cloud layers according to the continuity of the reflectivity, and calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer in the radial direction respectively;

[0020] The cloud amount calculation module is configured to calculate the cloud amount and the cloud amount in each radial direction through the cloud base height, cloud layer thickness, and reflectivity weighted value;

[0021] The real-time cloud amount acquisition module is configured to multiply the time corresponding to each radial direction by different weights to obtain the cloud amount at the current moment, output the result, and send the cumulative cloud amount into a loop to continuously obtain real-time cloud amount data.

[0022] The cloud layer segmentation and calculation module specifically includes the following:

[0023] In the radial direction, if there are more than N distance bins with non-zero reflectivity values in a region, and the proportion of distance bins with non-zero reflectivity values in this region exceeds a set value, then this region with continuous non-zero reflectivity values is a cloud layer, and there are at least N distance bins with zero values between cloud layers;

[0024] After cloud layer segmentation, calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer respectively. Among them, the cloud base height is the number of distance bins with non-zero reflectivity values in the first distance bin of this cloud layer multiplied by the distance resolution, the cloud layer thickness is the number of distance bins occupied between the first distance bin with non-zero reflectivity value and the last distance bin with non-zero reflectivity value in this cloud layer multiplied by the distance resolution, and the reflectivity weighted value is the sum of the average reflectivity of this cloud layer and the reflectivity threshold divided by 15.

[0025] The cloud amount calculation in the cloud amount calculation module includes:

[0026] According to the different cloud base heights, different coefficients are used to calculate the cloud amount. If the cloud base height is less than 0.5 km and the cloud layer thickness exceeds 0.6 km, it is considered that rain is about to fall or is falling, and it is in a full cloud state, and the cloud amount is the maximum value;

[0027] In other cases, the cloud amount is equal to the coefficient multiplied by the cloud layer thickness multiplied by the reflectivity weighted value. If the cloud base height is less than 2.5 km, this cloud layer is considered a low cloud, and the coefficient is 40. If the cloud base height is greater than 2.5 km and less than 8.5 km, this cloud layer is considered a middle cloud, and the coefficient is 35. If the cloud base height is greater than 8.5 km, this cloud layer is considered a high cloud, and the coefficient is 25.

[0028] The cloud amount calculation for each radial direction in the cloud amount calculation module includes:

[0029] According to the sum of the cloud amounts of each layer in the obtained radial direction, obtain the cloud amount in the radial direction. Set the maximum value of the cloud amount in each radial direction to 150. If the cloud amount in the last radial direction is greater than 100, the part exceeding 100 is accumulated into the cloud amount cumulative value. If the cloud amount in the last radial direction is less than 100 and the cloud amount cumulative value is greater than 0, use the cloud amount cumulative value to fill the last radial direction, with a maximum filling of 100. If the cloud amount in the last radial direction is less than 100 and the cloud amount cumulative value is less than 0, no processing is performed.

[0030] The present invention has the following advantages: A cloud amount calculation method and device based on a millimeter-wave cloud detector can estimate the cloud cover rate of the entire sky at the current moment by means of the cloud base height, cloud layer thickness, reflectivity intensity, etc. within a certain period of time. It can calculate the cloud amount well on the basis of removing clutter, improve the reliability of data, and lay a good foundation for the subsequent observation and processing of data. Accurately calculating the cloud amount helps to improve the accuracy of weather forecasting. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic flow chart of the present invention;

[0032] Figure 2 is a schematic diagram of the effect of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and illustrated herein are usually arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below with reference to the accompanying drawings is not intended to limit the protection scope of the present application claimed, but merely represents the selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the protection scope of the present application. The present invention will be further described below with reference to the accompanying drawings.

[0034] As Figure 1 shown, the present invention specifically relates to a cloud amount calculation method based on a millimeter-wave cloud detector. First, data preprocessing is performed, the radar data is cyclically input, and the latest radar base data is read. Then, clutter is removed according to the reflectivity threshold. Then, different cloud layers are segmented according to the continuity of the reflectivity. Then, the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer of cloud in the radial direction are calculated respectively. Then, the cloud amount of each layer of cloud in the radial direction and the cloud amount in the radial direction are calculated through the cloud base height, cloud layer thickness, and reflectivity weighted value. Finally, the cloud amount at the current moment is obtained by multiplying the time corresponding to each radial direction by different weights, the result is output, and the cumulative cloud amount is sent into the loop to continuously obtain real-time cloud amount data.

[0035] Further, the data preprocessing includes: inputting radar data, setting the cloud amount cumulative value cc_cum to 0, reading the latest radar base data. The present invention selects to obtain the data of the latest 30 minutes to obtain the basic reflectivity. A suitable threshold mm is selected to remove the clutter with lower reflectivity and reduce the misguidance to the subsequent cloud amount calculation.

[0036] Cloud layer segmentation includes: Radially, if there are more than 10 range bins with non-zero reflectivity values, and the proportion of range bins with non-zero reflectivity values in this area exceeds 70%, then the area with continuous non-zero reflectivity values is considered to be a cloud layer, and there is at least a 10-range-bin gap between cloud layers. After cloud layer segmentation, information such as the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer is calculated respectively. Among them, the cloud base height is the number of the first range bin with non-zero reflectivity value of this cloud layer multiplied by the range resolution, the cloud layer thickness is the number of range bins occupied between the first range bin with non-zero reflectivity value and the last non-zero reflectivity value of this cloud layer multiplied by the range resolution, and the reflectivity weighted value is the mean reflectivity of this cloud layer plus the sum of mm divided by 15.

[0037] Cloud amount calculation includes: Different coefficients are used to calculate the cloud amount according to different cloud base heights; if the cloud base height is extremely low (<0.5 km) and the cloud layer thickness exceeds 0.6 km, it is considered that rain is about to fall or is falling, and it is in a full cloud state, and the cloud amount is the maximum value; in other cases, the cloud amount = coefficient × cloud layer thickness × reflectivity weighted value. If the cloud base height is less than 2.5 km, this cloud layer is considered a low cloud, and the coefficient is 40; if the cloud base height is greater than 2.5 km and less than 8.5 km, this cloud layer is considered a middle cloud, and the coefficient is 35; if the cloud base height is greater than 8.5 km, this cloud layer is considered a high cloud, and the coefficient is 25.

[0038] The calculation of the cloud amount for each radial direction includes: The cloud amount in the radial direction is obtained based on the sum of the cloud amounts of each layer in the radial direction. To better simulate the process of the slow dissipation of cloud layers after rainfall, the maximum cloud amount for each radial direction is set to 150. If the cloud amount of the last radial direction is greater than 100, the part exceeding 100 is accumulated into cc_cum; if the cloud amount of the last radial direction is less than 100 and cc_cum > 0, then cc_cum is used to fill the last radial direction, with a maximum filling of 100; if the cloud amount of the last radial direction is less than 100 and cc_cum < 0, no processing is performed.

[0039] Time weighting includes: Different weights are assigned according to the different time distances of the corresponding time of the cloud amount in each radial direction from the current moment. The time weight for the first 2 / 3 is 1, and the time weight for the last 1 / 3 is 2. Since the maximum cloud amount set in the present invention is 150 and the maximum value for result output is 100, if the finally calculated result is greater than 100, it is changed to 100 for output. And cc_cum is sent to the data reading place to prepare for the calculation of the cloud amount at the next moment.

[0040] As Figure 2 shown, it is the cloud amount calculation effect of the millimeter-wave cloud detector. Among them, the left side is the reflectivity color scale, the right side is the cloud amount value, the broken line with "★" is the cloud amount of the all-sky imager, the broken line with "○" is the cloud amount calculated by the present invention, and the rest are radar reflectivity values. From Figure 2It can be seen that the change degrees of the two lines are very similar. The Pearson correlation coefficient is used to measure the correlation between the cloud amount calculated by the present invention and the cloud amount of the all-sky imager. The result shows a range of [-1, 1]. A value greater than 0 indicates a positive correlation between the two, and a value less than 0 indicates a negative correlation. The greater the absolute value, the higher the degree of correlation and the more reliable the present invention. During this rainfall process, the correlation coefficient between the two reaches 0.96, indicating that the present invention has good effects.

[0041] The above are only the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments. Instead, it can be used in various other combinations, modifications, and improvements, and can be changed within the scope of the concept described herein through the above teachings or the techniques or knowledge in related fields. Any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A cloud amount calculation method based on a millimeter-wave cloud detector, characterized in that: The calculation method includes: S1. Circularly input radar data, read the latest radar base data, and remove clutter according to the reflectivity threshold; S2. Segment different cloud layers according to the continuity of reflectivity, and calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer of cloud in the radial direction respectively; S3. Calculate the cloud amount and the cloud amount of each radial cloud through the cloud base height, cloud layer thickness, and reflectivity weighted value; S4. Multiply the time corresponding to each radial direction by different weights to obtain the cloud amount at the current moment, output the result, and send the cumulative cloud amount into the loop to continuously obtain real-time cloud amount data; The cloud amount calculation in S3 includes: According to different cloud base heights, different coefficients are used to calculate the cloud amount. If the cloud base height is less than 0.5 km and the cloud layer thickness exceeds 0.6 km, it is considered that rainfall is about to occur or is occurring, and it is in a full-cloud state, and the cloud amount is the maximum value; In other cases, the cloud amount is equal to the coefficient multiplied by the cloud layer thickness multiplied by the reflectivity weighted value. If the cloud base height is less than 2.5 km, the cloud layer is considered a low cloud, and the coefficient is 40. If the cloud base height is greater than 2.5 km and less than 8.5 km, the cloud layer is considered a middle cloud, and the coefficient is 35. If the cloud base height is greater than 8.5 km, the cloud layer is considered a high cloud, and the coefficient is 25.

2. The cloud amount calculation method based on a millimeter wave ceilometer according to claim 1, wherein: S2 includes: In the radial direction, if there is an area where the reflectivity has values in more than N range bins, and the proportion of range bins with valid reflectivity values in this area exceeds the set value, then this area with continuous reflectivity values is one layer of cloud, and there are at least N range bins without values between cloud layers; After cloud layer segmentation, calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer respectively. Among them, the cloud base height is the number of range bins with the first valid reflectivity value of this layer of cloud multiplied by the range resolution, the cloud layer thickness is the number of range bins occupied between the first range bin with a valid reflectivity value and the last range bin with a valid reflectivity value of this cloud layer multiplied by the range resolution, and the reflectivity weighted value is the sum of the average reflectivity of this cloud layer and the reflectivity threshold divided by 15.

3. The cloud amount calculation method based on a millimeter wave nephelometer according to claim 2, wherein: The calculation of the cloud amount of each radial direction in S3 includes: Based on the sum of the cloud amounts of each layer in the radial direction obtained, obtain the cloud amount in the radial direction. Set the maximum value of the cloud amount on each radial line to 150. If the cloud amount on the last radial line is greater than 100, then the part exceeding 100 is accumulated into the cloud amount cumulative value. If the cloud amount on the last radial line is less than 100 and the cloud amount cumulative value is greater than 0, then use the cloud amount cumulative value to fill the last radial line, with a maximum filling of 100. If the cloud amount on the last radial line is less than 100 and the cloud amount cumulative value is less than 0, no processing is performed.

4. A cloud amount calculation device based on a millimeter wave cloud detector, characterized in that: The device includes a data preprocessing module, a cloud layer segmentation and calculation module, a cloud amount calculation module, and a real-time cloud amount acquisition module; The data preprocessing module is configured to circularly input radar data, read the latest radar base data, and remove clutter according to the reflectivity threshold; The cloud layer segmentation and calculation module is configured to segment different cloud layers according to the continuity of reflectivity, and calculate the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer of cloud in the radial direction respectively; The cloud amount calculation module is configured to calculate the cloud amount and the cloud amount of each radial cloud through the cloud base height, cloud layer thickness, and reflectivity weighted value; The real-time cloud amount acquisition module is configured to multiply the time corresponding to each radial direction by different weights to obtain the cloud amount at the current moment, output the result, and send the cumulative cloud amount into a loop to continuously obtain real-time cloud amount data; The cloud amount calculation in the cloud amount calculation module includes: According to different cloud base heights, different coefficients are used to calculate the cloud amount. If the cloud base height is less than 0.5 km and the cloud layer thickness exceeds 0.6 km, it is considered that rain is about to fall or is falling, and it is in a full cloud state, and the cloud amount is the maximum value; In other cases, the cloud amount is equal to the coefficient multiplied by the cloud layer thickness multiplied by the reflectivity weighted value. If the cloud base height is less than 2.5 km, the cloud layer is considered a low cloud, and the coefficient is 40. If the cloud base height is greater than 2.5 km and less than 8.5 km, the cloud layer is considered a middle cloud, and the coefficient is 35. If the cloud base height is greater than 8.5 km, the cloud layer is considered a high cloud, and the coefficient is 25.

5. The cloud amount calculation device based on a millimeter wave nephelometer according to claim 4, wherein: The cloud layer segmentation and calculation module specifically includes the following: In the radial direction, if there are more than N regions with non-zero reflectivity in the distance bins, and the proportion of the distance bins with non-zero reflectivity in this region exceeds the set value, then this region with continuous non-zero reflectivity is a cloud layer, and there are at least N distance bins with zero value between cloud layers; After cloud layer segmentation, the cloud base height, cloud layer thickness, and reflectivity weighted value of each layer are calculated respectively. Among them, the cloud base height is the number of the first distance bin with non-zero reflectivity of this layer of cloud multiplied by the distance resolution, the cloud layer thickness is the number of distance bins occupied between the first distance bin with non-zero reflectivity and the last distance bin with non-zero reflectivity of this layer of cloud multiplied by the distance resolution, and the reflectivity weighted value is the sum of the average reflectivity of this layer of cloud and the reflectivity threshold divided by 15.

6. The cloud amount calculation device based on a millimeter wave nephelometer according to claim 4, characterized in that: The cloud amount calculation for each radial direction in the cloud amount calculation module includes: According to the sum of the cloud amounts of each layer in the radial direction, the cloud amount in the radial direction is obtained. The maximum value of the cloud amount on each radial direction is set to 150. If the cloud amount on the last radial direction is greater than 100, the part exceeding 100 is accumulated into the cloud amount cumulative value. If the cloud amount on the last radial direction is less than 100 and the cloud amount cumulative value is greater than 0, the cloud amount cumulative value is used to fill the last radial direction, with a maximum filling of 100. If the cloud amount on the last radial direction is less than 100 and the cloud amount cumulative value is less than 0, no processing is performed.

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