CN-121634106-B - Three-dimensional wind field inversion method and device for satellite-borne cone scanning Doppler radar

CN121634106BCN 121634106 BCN121634106 BCN 121634106BCN-121634106-B

Abstract

The invention provides a three-dimensional wind field inversion method and device for a satellite-borne cone scanning Doppler radar, wherein a radar observation strip area is divided into a plurality of sub-blocks, area overlapping exists between adjacent sub-blocks, horizontal wind fields of all height layers are parameterized in each sub-block according to a segmentation continuity variation assumption, optimal horizontal wind field parameters of all height layers in each sub-block are obtained by using a variation method, horizontal wind fields in all sub-blocks are determined according to the optimal horizontal wind field parameters, the horizontal wind fields at corresponding positions of all sub-blocks in the overlapping area are subjected to linear weighted fusion to obtain a final horizontal wind field, horizontal divergence is calculated according to the optimal horizontal wind field parameters of all height layers in each sub-block, the horizontal divergence is integrated in the height direction by using an atmospheric mass conservation equation to obtain a vertical wind field, and the vertical wind fields at corresponding positions of all sub-blocks in the overlapping area are subjected to linear weighted fusion to obtain the final vertical wind field. The invention realizes continuous and steady three-dimensional wind field inversion of the satellite-borne cone scanning Doppler radar.

Inventors

HUANG HAO
ZHAO WENXUAN
ZHAO KUN
LU CHEN
CHEN HAIQIN

Assignees

南京大学

Dates

Publication Date: 20260508
Application Date: 20260203

Claims (8)

1. The three-dimensional wind field inversion method of the satellite-borne cone scanning Doppler radar is characterized by comprising the following steps of: dividing a radar observation strip area into a plurality of sub-blocks, wherein the adjacent sub-blocks have area overlapping, and parameterizing the horizontal wind field of each height layer by using a segmentation continuity variation assumption in each sub-block; acquiring optimal horizontal wind field parameters of each height layer in each sub-block by using a variation method, determining horizontal wind fields in each sub-block according to the optimal horizontal wind field parameters, and carrying out linear weighted fusion on the horizontal wind fields at the corresponding positions of each sub-block in the overlapping region to obtain a final horizontal wind field; calculating horizontal divergence according to optimal horizontal wind field parameters of each height layer in each sub-block, integrating the horizontal divergence in the height direction by using an atmospheric mass conservation equation to obtain vertical wind fields, and carrying out linear weighted fusion on the vertical wind fields at the corresponding positions of the sub-blocks in the overlapping region to obtain a final vertical wind field; inversion is performed in a satellite orbit coordinate system, the direction parallel to the satellite running direction is recorded as the x direction, the direction perpendicular to the satellite running direction is recorded as the y direction, the left side of the running direction is positive, and the horizontal wind field of each height layer is parameterized in each subblock by the following linear change formula: ; ; Wherein x and y are distances in x direction and y direction respectively of the observation point relative to the start point of the sub-block, 、 Is the corresponding wind speed; And Is the wind speed at the starting point within each sub-block, And Respectively is The average linear rate of change in the x and y directions, And Respectively is Average linear rate of change in x and y directions, horizontal wind field parameters are 、、、、 And ; The optimal horizontal wind field parameters of each height layer in each sub-block are obtained by using a variation method, and the cost function is as follows: ; Wherein, the As a function of the total cost of the device, For the observation term, the difference between the observed radial velocity and the radial velocity calculated based on the parameterized wind field is represented, As background item, representing the difference between wind field parameters and statistical characteristic parameters, parameters To control background items Relative to the observation term Is a weight of (2).
2. The three-dimensional wind field inversion method of the spaceborne cone scanning Doppler radar according to claim 1, wherein the formula of the observation term is: ; Wherein, the The number of the effective observation points; Is a vector of parameters of the horizontal wind field, ; Is the first A radial velocity observation quantity is obtained, In order to correspond to the equivalent radial velocity, , Is the average falling speed of the condensate; is the observation error of the radial velocity; Is the first The corresponding coefficient vector is observed for each radial velocity, , , , And Respectively the first Two components of horizontal wind at each observation point 、 Geometric coefficients projected into the radar line-of-sight direction, And Respectively the first The observation points are located at the starting point of the sub-block And displacement in the y direction; And The elevation angle of the radar beam of the observation point relative to the horizontal plane and the azimuth angle relative to the y direction are respectively; The formula of the background term is: ; Wherein, the Is the first The parameters of the horizontal wind field are set, And (3) with Respectively the first Expected values and standard deviations of individual horizontal wind field parameters.
3. The three-dimensional wind field inversion method of the spaceborne cone scanning Doppler radar according to claim 1, wherein the method for obtaining the optimal horizontal wind field parameters of each height layer in each sub-block by using a variation method comprises the following steps: in the inversion process by using the variation method, the L-BFGS-B method is adopted to carry out iterative solution, and the optimal horizontal wind field parameters of each height layer in each sub-block are obtained, so that the cost function is minimum.
4. The method for three-dimensional wind field inversion of a spaceborne cone scanning doppler radar according to claim 1, wherein the horizontal divergence is calculated according to the optimal horizontal wind field parameters of each altitude layer in each sub-block by the following formula: ; Wherein, the Expressed in horizontal coordinates And vertically is first Layer height The horizontal divergence of the positions of the two, Is that At the height of The average linear rate of change in the x-direction, Is that At the height of Average linear rate of change in the y direction.
5. The method for inverting a three-dimensional wind field of a spaceborne cone scanning doppler radar according to claim 4, wherein the vertical wind field is obtained by integrating the horizontal divergence in the height direction by using an atmospheric mass conservation equation by the following formula: ; Wherein, the For the vertical speed of the kth level, For the reference height to be used, For the boundary conditions at the corresponding height, For the kth level layer, Is a temporary height variable in the integral.
6. The three-dimensional wind field inversion method of the spaceborne cone scanning doppler radar according to any one of claims 1-5, wherein the method is characterized in that the method comprises the steps of carrying out linear weighted fusion on a horizontal wind field and a vertical wind field at corresponding positions of sub-blocks in an overlapping region to obtain a final inversion result of the whole inversion region, and further comprising: And converting the final horizontal wind field projection into a geographic wind field.
7. The three-dimensional wind field inversion device for the satellite-borne cone scanning Doppler radar is characterized by being applied to the three-dimensional wind field inversion method for the satellite-borne cone scanning Doppler radar according to any one of claims 1 to 6, and comprising the following steps: The parameterization module is used for dividing the radar observation strip area into a plurality of sub-blocks, wherein the adjacent sub-blocks are overlapped, and the horizontal wind field of each height layer is parameterized by the assumption of piecewise continuity change in each sub-block; The first calculation module is used for obtaining optimal horizontal wind field parameters of each height layer in each sub-block by using a variation method, determining horizontal wind fields in each sub-block according to the optimal horizontal wind field parameters, and carrying out linear weighted fusion on the horizontal wind fields at the corresponding positions of each sub-block in the overlapping area to obtain a final horizontal wind field; And the second calculation module is used for calculating the horizontal divergence according to the optimal horizontal wind field parameters of each height layer in each sub-block, integrating the horizontal divergence in the height direction by utilizing an atmospheric mass conservation equation to obtain a vertical wind field, and carrying out linear weighted fusion on the vertical wind field at the corresponding position of each sub-block in the overlapping area to obtain a final vertical wind field.
8. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the method of three-dimensional wind field inversion of a spaceborne cone scanning doppler radar as claimed in any one of claims 1 to 6 when the program is executed by the processor.

Description

Three-dimensional wind field inversion method and device for satellite-borne cone scanning Doppler radar Technical Field The invention relates to the technical field of weather forecast, in particular to a three-dimensional wind field inversion method and device for a satellite-borne cone scanning Doppler radar. Background In order to obtain horizontal wind information in the global cloud, in recent years, students have proposed a concept of adopting a satellite-borne cone scanning radar, and orthogonal components of a wind field (as shown in fig. 1) are obtained by intersecting front-side and rear-side wave beams of the radar at certain points through rotation to form multi-view observation, so that inversion of the full wind field from radial wind becomes possible. Since this radar still belongs to the conceptual radar, a mature wind field inversion method is lacking. However, wind park inversion itself is a classical problem in the field of weather radars, especially ground based radars, single radar inversion methods, dual/multiple doppler inversion methods, etc. have been developed. VAD (Velocity-Azimuth Display) can invert radial Velocity Azimuth scanning observations of one or more elevation angles by using a single radar, inverting profiles such as wind direction, falling speed, irradiance/deformation, etc. by harmonic fitting. This approach requires that the wind field be uniform or only have linear variation over the assumed azimuth scan range, which assumption has significantly reduced applicability as the scan radius increases. The orbit height of the spaceborne radar is generally more than 500 km, the horizontal diameter of the conical scanning is 800 km, and the orbit height exceeds the dimensions of a plurality of weather systems, so that the assumption error of uniform wind fields or linear change is large, and accurate wind field inversion is difficult to realize by using a VAD method. The inversion of the foundation double/multiple Doppler wind fields is based on radial wind observation of intersection of two or more radars in the same observation area, and the horizontal wind component of the intersection point is obtained by solving a simplified horizontal wind and radial wind mapping equation. The foundation radar can invert a three-dimensional wind field with high spatial resolution through multi-elevation dense volume scanning networking observation. The satellite-borne cone scanning radar is positioned on a moving platform, can acquire the observation of the orthogonal components of the wind field in the same area by utilizing the front and rear side beams in a short time, however, due to the fact that the moving platform is too fast, single elevation angle is adopted, doppler observation junction points with proper intersection angles are distributed sparsely, and therefore a classical dual-Doppler wind field inversion method can only be adopted to obtain sparse point wind fields, and vertical airflow can obviously influence inversion accuracy under the influence of the large elevation angle of the satellite-borne radar. The three-dimensional wind field inversion of the satellite-borne cone scanning Doppler radar is an underdetermined problem, and the difficulties mainly comprise: 1. Inversion applicability in ultra-large spatial scale and significantly non-uniform wind fields In the case of satellite borne radars observing and covering hundreds of kilometers, and the target system often varies unevenly/nonlinearly, how to improve the "uniform or low-order variation" assumption on which VAD methods depend to adapt to strong shear, strong convection and fast evolution fields is the first difficulty of inversion. 2. Sparse and uneven distribution of multi-view intersection points caused by satellite-borne cone scanning mode In the operation of the spaceborne cone scanning radar, front and rear survey beams can be intersected to form multi-view observation to acquire orthogonal components of a wind field. However, because the running speed is higher, the distance between the track lines of the same azimuth angle reaches several tens of kilometers (particularly related to the running speed of the satellite and the radar cone scanning period), so that the intersection points are sparse and unevenly distributed (the intersection points are densely distributed from the undersea point to the two sides), and meanwhile, the intersection angles corresponding to the intersection points are different (reduced to the two sides) at different distances from the undersea point. The characteristics lead to the obvious difference of the orthogonal wind field observation information of different areas, and are a second difficulty of inversion. 3. Horizontal and vertical information aliasing under satellite-borne large elevation angle observation geometry The observed radial velocity is the amount of coupling of horizontal wind, vertical velocity and particle fall velocity. The observation beam of the s