KR20130060400A - The method generating cappi data efficiently by subdividing search area on the radial radar - Google Patents

Abstract

PURPOSE: A method is provided to include a program record medium in order to execute a system which efficiently extracts only the necessary parts of an UF data when generating a CAPPI(Constant Altitude Plan Position Indicator) data by subdividing a search area when observing the volume of a radial shape radar. CONSTITUTION: A system which increases an efficiency of a CAPPI data generation by subdividing a search area when observing a volume of a radial shape radar includes a step for interpreting an azimuth range and a ground distance range in a given CAPPI area target and a step for correcting a distance range according to a double specific altitude angle.

Description

The method Generating CAPPI Data Efficiently by subdividing search Area on the Radial Radar}

Efficient generation and construction of RADAR rainfall raster data

Numerical calculation of binary file format processing technology, Raw Radar Data Format (Universal Format, etc.), Radar measurement data in 3D space

In general, weather radar observation methods include a fixed position of the altitude and a rotation of the antenna to observe (Plan Position Indicator: PPI) and repeated observation while changing the antenna elevation angle (Volume Scan). Among the radar observation data of UF format calculated by the Korea Meteorological Administration, PPI is the information of radio reflectivity observed by rotating 360 degrees at a certain altitude. Therefore, the central root near the observation location is at low altitude, and the observation is at higher altitude as distance increases. Central roots have low observation altitudes and are affected by terrain, and at higher distances, altitudes increase.

In estimating ground rainfall, it is common to use the Constant Altitude Plan Position Indicator (CAPPI) to estimate rainfall from radio wave reflectance at the same altitude (1.5 km, etc.). In order to calculate the CAPPI, the PPI extracted from the UF file is used, and the space is calculated using the published Mohr method. In order to perform the memory-based processing, DISK I / O is performed for all elevation angles stored in the UF file, for all azimuth angles (0 to 360 degrees), and for all distances (0 to 250 km for Gwangdeoksan, Korea Meteorological Agency). After checking the information through the memory loading process, the space calculation (Mohr method, etc.) is performed. If the area of CAPPI data required (typically non-radial lattice rasters) is part of the spatial range of UF data, the full-area full scan method is inefficient.

In the present invention, to implement a technique for efficiently extracting only the necessary portion of the UF data when generating CAPPI.

In order to achieve the above objects, the system for subtracting the search area during the volume observation of the radial radar according to the present invention to streamline the generation of the copy data, the module for analyzing the azimuth range and the ground surface distance range in a given target CAPPI region, Among them, it characterized by consisting of a module for correcting the distance range according to a specific elevation angle. The present invention is characterized in that it comprises a recording medium having recorded thereon a program for executing the system for subdividing the search area during the volume observation of the radial radar to streamline the generation of copy data.

Through the present invention, it is possible to process data faster than before when extracting a specific area cappi in a radial RADAR data format such as UF format. The improvement is better when the target CAPPI area is narrower than the radar observation space range.

Test Environment Intet (R) Core (TM) i7-2600 3.4GHz, 16GB Ram, Windows 7 64bit, 2010.12.10. In order to generate CAPPI for Gwangdeoksan radar site at 16:21, the effect of time reduction in extracting PPI information for all elevation angles is as follows.

0 ~ 360 degree azimuth whole area: 20 seconds

180 ~ 360 degree azimuth: 12 seconds

Distance 50 ~ 200km, Azimuth 180 ~ 360: 8 seconds

Distance 50 ~ 200km, Azimuth 210 ~ 300: 6 seconds

1 is an example of a CAPPI image provided by the Korea Meteorological Administration (Gwangdeoksan, 2010-12-10 16:21).
2 is part of the UF data structure published on the Internet (sigmet.com).
FIG. 3 is an exemplary diagram when the extraction target CAPPI area is given as a rectangle with respect to the elevation angle of 0 degrees, that is, the ground plane, and 0 is the radar observation origin.
4 is an exemplary diagram illustrating a correlation between the distance from the ground plane (elevation angle = 0 degrees) and the distance from the PPI plane which is the elevation angle PHI with respect to the elevation angle PHI.
5 is a functional example of an API form for data processing when the azimuth and distance range segmentation function is implemented.
Fig. 6 is an example of PPI extraction visualization for the lowest elevation angle (Fig. 1 location and viewpoint).
Figure 7 is an example of azimuth 180-360 degree filtering PPI extraction visualization for the lowest altitude (Fig. 1 position and viewpoint).
8 is an example of visualization of filtering PPI extraction with azimuth angles of 180 to 360 degrees and distances of 50 to 250 km for a minimum elevation angle.
9 is an example of visualization of filtering PPI extraction with azimuth angle of 210 to 330 degrees and a distance of 50 to 200 km for a minimum elevation angle.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art may easily utilize the present invention.

The present invention does not consider the earth curvature for easy understanding, and the CAPPI generation region is included in one quadrant (azimuth angle of 0 to 90 degrees). 3 illustrates a case where a target area for generating a CAPPI is presented with respect to an elevation angle of 0 degrees, that is, a ground surface.

When the CAPPI generation target raster area is designated, each edge coordinate p1, p2, p3, p4 can be determined. In the case of ESRI ASC format, the most representative raster data format, the lower left reference point is secured through the LLcorner or LLcenter of the header, and the upper left, upper right and lower right corner points are determined by rols, cols and cellsize of the header. The polar coordinates of p1 converted to polar coordinates for the UF data of the radial coordinate system are shown in the following equation.

After repeating the same process for p2, p3, and p4, the azimuth and distance ranges required for the UF data can be determined as follows.

Since the distance in the PPI plane is larger than the distance on the ground as shown in FIG. 4, it is necessary to correct the extraction distance range for the specific elevation angle (PHI) distance. You can correct it with the following formula.

Claims (1)

Interpreting the azimuth range and ground surface distance range in a given target CAPPI region; Compensating the distance range according to a specific altitude angle, the system for streamlining the generation of the copy data by subdividing the search area during the volume observation of the radar radar characterized in that

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