阅读说明：本技术 一种基于星地同步观测对比的卫星闪电探测评估方法 (Satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison ) 是由 惠雯 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种基于星地同步观测对比的卫星闪电探测评估方法,其特征在于,包括如下步骤,S1:对一个典型区域在特定时间段内星地同步观测的闪电进行对比,以说明卫星与地基闪电探测结果的相关性和差异性；S2:为解决卫星与地基探测闪电信号不同表现形式的问题,根据地闪回击数据的时空粒度特征,从卫星探测的逐帧像元数据中提取一种新的卫星探测闪电数据单元spot,使其在时空粒度上与地基stroke具有可比性；S3:为解决卫星与地基观测闪电种类不完全一致的问题,找到卫星与地基可以同时观测闪电的特定位置；S4:对特定区域的卫星与地基闪电探测结果进行比对,定义二者的匹配度。(The invention discloses a satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison, which is characterized by comprising the following steps of S1, comparing lightning synchronously observed by a satellite and ground in a specific time period in a typical area to explain the correlation and difference of the satellite and foundation lightning detection results; s2, in order to solve the problem that the lightning signals of the satellite and the foundation detection have different expression forms, a new satellite detection lightning data unit spot is extracted from the frame-by-frame pixel data of the satellite detection according to the space-time granularity characteristics of the ground flash back-hit data, so that the satellite detection lightning data unit spot has comparability to the foundation stroke on the space-time granularity; s3, in order to solve the problem that the types of the lightning observed by the satellite and the foundation are not completely consistent, finding out the specific position where the satellite and the foundation can simultaneously observe the lightning; and S4, comparing the satellite of the specific area with the foundation lightning detection result, and defining the matching degree of the satellite and the foundation lightning detection result.)

1. A satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison is characterized by comprising the following steps:

s1, comparing the lightning synchronously observed by the satellite and the ground in a typical area in a specific time period to illustrate the correlation and difference of the lightning detection results of the satellite and the ground;

s2, in order to solve the problem that the lightning signals of the satellite and the foundation detection have different expression forms, a new satellite detection lightning data unit spot is extracted from the frame-by-frame pixel data of the satellite detection according to the space-time granularity characteristics of the ground flash back-hit data, so that the satellite detection lightning data unit spot has comparability to the foundation stroke on the space-time granularity;

s3, in order to solve the problem that the types of the lightning observed by the satellite and the foundation are not completely consistent, finding out the specific position where the satellite and the foundation can simultaneously observe the lightning;

and S4, comparing the satellite of the specific area with the foundation lightning detection result, and defining the matching degree of the satellite and the foundation lightning detection result.

2. The satellite lightning detection and evaluation method based on geosynchronous satellite observation and comparison as claimed in claim 1, wherein the specific time period in the step S1 is 2008-.

3. The satellite lightning detection and evaluation method based on geosynchronous satellite observation and contrast of claim 1, wherein the satellite data in the step S1 uses TRMM LIS data, the observation area is 38 ° N to 38 ° S, the average fixation time at each observation point is 90S, and the spatial resolution of the sub-satellite point is 3 to 6 km; the foundation data uses the national lightning monitoring network ADTD, the observation range is the land area of China, and the single-station radiation radius is 300 km.

4. The satellite lightning detection and evaluation method based on satellite-ground synchronous observation and comparison as claimed in claim 3, characterized in that the research area is selected from the southwest region of China.

5. The satellite lightning detection and assessment method based on satellite-ground synchronous observation and comparison according to claim 1, wherein for said step S3, finding the specific location where the satellite and the ground can observe the lightning at the same time comprises the following steps:

s31, according to the satellite orbit information, the ECR coordinates of the satellite at each observation time point are converted into longitude S under a geodetic coordinate system_lonLatitude S_latAnd elevation h_sThe conversion is performed using the following equations:

wherein X is ECR horizontal coordinate, Y is ECR vertical coordinate, Z is ECR vertical coordinate, a is earth long radius, b is earth short radius, e²In order to achieve the first eccentricity ratio,

because the satellite orbit height is unchanged, the model is simplified into the following steps:

s32, obtaining cloud boundary distribution and cloud height h through cloud detection and cloud height inversion_c；

S33 longitude C according to cloud boundary point_lonAnd latitude C_latSatellite Susbaster Point longitude S_lonAnd latitude S_latCalculating the spherical distance of the satellite relative to the cloud boundary position, and calculating the spherical distance of the satellite relative to the cloud boundary position by using the following formula:

the SOC is an included angle between a satellite subsatellite point and a cloud boundary position relative to the center of the earth;

s34 calculating effective radius l of satellite detection lightning_sThe effective radius l of the satellite detection lightning is calculated using the following formula_s：

Wherein R is the radius of the earth and the height h of the satellite_sHeight of cloud h_cThe radius of the earth R and the SOC are substituted into the formula to obtain,

s35 detecting effective radius l of lightning according to satellite_sAnd the observation range of the satellite at each observation point, and determining the area where the satellite and the foundation can simultaneously observe lightning as the specific area.

6. A satellite lightning detection evaluation method based on satellite-ground synchronous observation contrast according to claim 1 or 5, characterized in that for the step S4, the matching degree of the satellite of the specific area and the ground lightning detection is defined as:

Technical Field

The invention relates to the technical field of satellite lightning detection, in particular to a satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison.

Background

Lightning is a phenomenon of strong discharge in the atmosphere in an ultra-long distance, is a product generated when a convective weather system develops to a certain stage, effectively monitors a lightning signal, and has guiding significance for researching the indication effect of the lightning on the strong convective weather, the influence of the lightning on the atmospheric environment and the climate and the like.

The satellite lightning imager extracts the lightning signal through spectral filtering, spatial filtering, temporal filtering, and a background dimming technique of a Real Time Event Processor (RTEP) on the satellite. However, satellite lightning detection may cause artificial splitting of natural lightning, so that a lightning is divided into two frames of data or into a plurality of adjacent detection units, and therefore, the lightning information needs to be reconstructed by using different levels of data through a ground system.

The basic data unit of satellite lightning detection is lightning events (events), and in the process of in-orbit operation of a satellite lightning imager, due to internal reasons of the imager or external environment interference of an orbit, a large number of luminous pixels formed by non-lightning signals are often included in original lightning data and are called false lightning events.

In the process of satellite lightning detection, on one hand, errors may be introduced in the background estimation and background filtering processes of RTEP satellite processing, and on the other hand, false lightning signals may be filtered out to cause misjudgment, such factors inevitably affect the satellite lightning detection result, so that an effective method is needed to evaluate the accuracy of satellite lightning detection, the lightning signals detected by the satellite can be verified by using lightning information observed by a foundation lightning positioning network, the satellite lightning detection result is detected through the matching degree of the lightning signals and the lightning signals, but the characteristics of target signals observed by the satellite and the foundation are different, and the two kinds of observation data cannot be directly compared.

Disclosure of Invention

Aiming at the technical problems in the related art, the invention provides a satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison, which can overcome the defects in the prior art.

In order to achieve the technical purpose, the technical scheme of the invention is realized as follows:

a satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison is characterized by comprising the following steps:

s1, comparing the lightning synchronously observed by the satellite and the ground in a typical area in a specific time period to illustrate the correlation and difference of the lightning detection results of the satellite and the ground;

s2, in order to solve the problem that the lightning signals of the satellite and the foundation detection have different expression forms, a new satellite detection lightning data unit spot is extracted from the frame-by-frame pixel data of the satellite detection according to the space-time granularity characteristics of the ground flash back-hit data, so that the satellite detection lightning data unit spot has comparability to the foundation stroke on the space-time granularity;

s3, in order to solve the problem that the types of the lightning observed by the satellite and the foundation are not completely consistent, finding out the specific position where the satellite and the foundation can simultaneously observe the lightning;

and S4, comparing the satellite of the specific area with the foundation lightning detection result, and defining the matching degree of the satellite and the foundation lightning detection result.

Further, the specific time period in the step S1 is 2008 + 2013.

Further, the satellite data in the step S1 uses TRMM LIS data, an observation region is between 38 ° N and 38 ° S, an average fixation time at each observation point is 90S, and a spatial resolution of the sub-satellite point is 3-6 km; the foundation data uses the national lightning monitoring network ADTD, the observation range is the land area of China, and the single-station radiation radius is 300 km.

Wherein, the research area is selected from the southwest area of China.

Further, for the step S3, finding a specific location where the satellite and the foundation can observe the lightning simultaneously may include the following steps:

s31, according to the satellite orbit information, the ECR coordinates of the satellite at each observation time point are converted into longitude S under a geodetic coordinate system_lonLatitude S_latAnd elevation h_sThe conversion is performed using the following equations:

wherein X is ECR horizontal coordinate, Y is ECR vertical coordinate, Z is ECR vertical coordinate, a is earth long radius, b is earth short radius, e²In order to achieve the first eccentricity ratio,

because the satellite orbit height is unchanged, the model is simplified into the following steps:

s32, obtaining cloud boundary distribution and cloud height h through cloud detection and cloud height inversion_c；

S33 longitude C according to cloud boundary point_lonAnd latitude C_latSatellite Susbaster Point longitude S_lonAnd latitude S_latCalculating the spherical distance of the satellite relative to the cloud boundary position, and calculating the spherical distance of the satellite relative to the cloud boundary position by using the following formula:

the SOC is an included angle between a satellite subsatellite point and a cloud boundary position relative to the center of the earth;

s34 calculating effective radius l of satellite detection lightning_sThe effective radius l of the satellite detection lightning is calculated using the following formula_s：

Wherein R is the radius of the earth and the height h of the satellite_sHeight of cloud h_cThe radius of the earth R and the SOC are substituted into the formula to obtain,

s35 detecting effective radius l of lightning according to satellite_sAnd the observation range of the satellite at each observation point, determining the distance between the satellite and the foundationAnd simultaneously observing the lightning area as a specific area.

Further, for the step S4, the matching degree of the satellite of the specific area and the ground-based lightning detection is defined as:

。

the invention has the beneficial effects that: the method utilizes the lightning information observed by the foundation lightning positioning network to verify the lightning signal detected by the satellite, detects the satellite lightning detection result through the matching degree of the lightning information and the lightning signal, and carries out quantitative evaluation on the satellite lightning detection result, thereby creating favorable conditions for more effectively monitoring the lightning signal on a satellite platform and realizing the tracking and early warning of a strong convection weather system.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flowchart illustrating steps of a satellite lightning detection evaluation method based on satellite-ground synchronous observation contrast according to an embodiment of the present invention;

FIG. 2 is a monthly change line graph of relative variation of satellite flash and ground flash in the southwest area of China according to the satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison in the embodiment of the invention;

FIG. 3 is a daily variation line graph of relative variation of satellite flash and ground flash in southwest of China according to the satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison in the embodiment of the invention;

FIG. 4 is a monthly change line graph of absolute variation of satellite flash and ground flash in the southwest area of China according to the satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison in the embodiment of the invention;

FIG. 5 is a daily variation line graph of absolute variation of satellite flash and ground flash in the southwest area of China according to the satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison in the embodiment of the invention;

FIG. 6 is a star-to-earth matching degree monthly change line graph in 2008 + 2013 in the southwest area of China according to the satellite lightning detection evaluation method based on synchronous satellite-to-earth observation and comparison according to the embodiment of the invention;

fig. 7 is a star-earth matching degree-day change line graph in 2008 + 2013 in the southwest area of China according to the satellite lightning detection evaluation method based on synchronous satellite-earth observation and comparison according to the embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

As shown in fig. 1 to 7, a satellite lightning detection evaluation method based on satellite-to-ground synchronous observation contrast according to an embodiment of the present invention is characterized by including the following steps:

s1, comparing the lightning synchronously observed by the satellite and the ground in a typical area in a specific time period to illustrate the correlation and difference of the lightning detection results of the satellite and the ground;

s2, in order to solve the problem that the lightning signals of the satellite and the foundation detection have different expression forms, a new satellite detection lightning data unit spot is extracted from the frame-by-frame pixel data of the satellite detection according to the space-time granularity characteristics of the ground flash back-hit data, so that the satellite detection lightning data unit spot has comparability to the foundation stroke on the space-time granularity;

s3, in order to solve the problem that the types of the lightning observed by the satellite and the foundation are not completely consistent, finding out the specific position where the satellite and the foundation can simultaneously observe the lightning;

and S4, comparing the satellite of the specific area with the foundation lightning detection result, and defining the matching degree of the satellite and the foundation lightning detection result.

In one embodiment, the specific time period in step S1 is 2008 + 2013.

In a specific embodiment, the satellite data in step S1 uses TRMM LIS data, the observation region is between 38 ° N and 38 ° S, the average fixation time at each observation point is 90S, and the spatial resolution of the sub-satellite point is 3-6 km; the foundation data uses the national lightning monitoring network ADTD, the observation range is the land area of China, and the single-station radiation radius is 300 km.

Preferably, the research area is selected from the southwest area of China.

In one embodiment, for step S2, it can be seen from table 1 that LISspot and ADTD stroke in 2008 + 2013 in the southwest region of our country have similar values of space-time granularity.

TABLE 1 LIS spot and ADTD stroke space-time granularity numerical table

	Time granularity(s)	Spatial granularity (km)
			LIS spot	0.111	2.143
ADTD stoke	0.146	2.271

In one embodiment, for step S3, to solve the problem that the types of lightning observed on the satellite and the foundation are not completely consistent, the influence of the cloud is considered to find a specific location where the satellite and the foundation can observe the lightning simultaneously, which includes the following steps:

s31, according to the satellite orbit information, the ECR coordinates of the satellite at each observation time point are converted into longitude S under a geodetic coordinate system_lonLatitude S_latAnd elevation h_sThe conversion is performed using the following equations:

wherein X is ECR horizontal coordinate, Y is ECR vertical coordinate, Z is ECR vertical coordinate, a is earth long radius, b is earth short radius, e²In order to achieve the first eccentricity ratio,

because the satellite orbit height is unchanged, the model is simplified into the following steps:

s32, obtaining cloud boundary distribution and cloud height h through cloud detection and cloud height inversion_c；

S33 longitude C according to cloud boundary point_lonAnd latitude C_latSatellite Susbaster Point longitude S_lonAnd latitude S_latCalculating the spherical distance of the satellite relative to the cloud boundary position, and calculating the spherical distance of the satellite relative to the cloud boundary position by using the following formula:

the SOC is an included angle between a satellite subsatellite point and a cloud boundary position relative to the center of the earth;

s34 calculating effective radius l of satellite detection lightning_sThe effective radius l of the satellite detection lightning is calculated using the following formula_s：

Wherein R is the radius of the earth and the height h of the satellite_sHeight of cloud h_cThe radius of the earth R and the SOC are substituted into the formula to obtain,

s35 detecting effective radius l of lightning according to satellite_sAnd the observation range of the satellite at each observation point, and determining the area where the satellite and the foundation can simultaneously observe lightning as the specific area.

In one embodiment, the radius a, b and the eccentricity e of the earth in step S31²Reference ellipsoid parameters recommended in 1975 for the international association of geodetic surveying and geophysical.

In a specific embodiment, for step S4, the matching degree of the satellite of the specific area and the ground-based lightning detection is defined as:

。

in order to facilitate understanding of the above-described technical aspects of the present invention, the above-described technical aspects of the present invention will be described in detail below in terms of specific usage.

When the satellite lightning detection evaluation method based on satellite-ground synchronous observation and comparison is used specifically, firstly, lightning synchronously observed by the satellite and the ground in a typical area in a specific time period is compared to illustrate the correlation and difference of the lightning detection results of the satellite and the foundation, and in the step, a research area selects the southwest area of China; then, according to the space-time granularity characteristics of the ground lightning return data, a new satellite detection lightning data unit spot is extracted from frame-by-frame pixel data detected by a satellite, so that the satellite detection lightning data unit spot has comparability to a foundation stroke on the space-time granularity, and the problem of different expression forms of a satellite detection lightning signal and a foundation detection lightning signal is solved; finding out a specific position where the satellite and the foundation can observe lightning simultaneously; finally, comparing the satellite and foundation lightning detection results in a specific area, defining the matching degree of the satellite and the foundation lightning detection results, and if the matching degree is close to 1, showing that the comparability of the satellite and the foundation lightning detection data can be obviously improved by using the algorithm.

In summary, after the algorithm in the invention is used to define the satellite-ground matching degree in 2008 + 2013 in the southwest region of China, the satellite-ground matching degree in the monthly change is 0.82, and the satellite-ground matching degree in the daily change is 0.81, which are both close to 1, which shows that the algorithm can obviously improve the comparability of the satellite and the foundation lightning detection data. Therefore, when a satellite lightning detection result is evaluated, lightning events output by the on-satellite real-time event processor are converted into lightning spots, then lightning located at a specific position is extracted from the lightning spots, and the lightning is compared with a ground observation result, so that a more accurate detection result can be obtained.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.