Data that effectively demonstrate the benefits of a 3D CAPPI algorithm

The data presented in this article are related to the research article entitled “Three-dimensional analysis of the initial stage of convective precipitation using an operational X-band polarimetric radar network” [1]. The data presented were obtained using a three-dimensional constant-altitude plan-position-indicator (3D CAPPI), which was generated by a new method proposed by [1]. The data used to create the 3D CAPPI were derived from two X-band polarimetric radar installations in the Kanto region of Japan, Ebina (139.39°E, 35.40°N), and Shin-yokohama (139.60°E, 35.51°N). These data are superior to operational radar data in terms of their temporal and spatial resolution. These high resolution data can indicate a rapidly developing storm, such as localized precipitation. It is particularly important to understand the early stages of storms in terms of numerical and short-term models. These data show the time of appearance, life cycle, and evolution of each cell that constitutes a storm in three-dimensional detail.


Data
The data presented here were observed by two radar installations in the Kanto area on 19 July 2012. The observation target was a rapidly developing storm that evolved over a short period of time and was observed on radar from 1210 LST to 1249 LST. The specifications of the two X-band polarimetric radars are shown in Table 1, while Fig. 1 shows the location of the radar installations and the area of the observation target. The beam-height cross sections in Fig. 2 [1] shows elevation angles for each radar.

High spatio-temporal resolution data
The data presented here were derived from observational radar data, with the application of temporal and spatial interpolation [1]. The high-resolution data were created at 30-s intervals in time (Animation 1 of Appendix A) and 0.1 intervals in space (Animation 2 of Appendix A).

Subject area
Atmospheric Research More specific subject area Meteorology Type of data Animation files How data were acquired X-band polarimetric radar observations Data format Raw, filtered, and analyzed

Experimental factors
The data were collected at 5 min intervals Experimental features High-spatiotemporal-resolution volumetric data modified using a new algorithm.

Data accessibility
The data are presented with this article as a supplementary animation file Value of the data The data presented here are considered to be superior to existing radar data in terms of their temporal and spatial resolution. The data demonstrate the overall storm structure and temporal evolution during its initial stage. The data provide several polarimetric parameters. Using these polarimetric parameters, other researchers can study the microphysical processes related to the evolution of storms [2e5]. This data can assist in making accurate forecasts by improving the initial conditions in numerical and short-term models [6].
The research data provide users with more detailed information for targets observed by radar. The algorithm generating these data can be applied to various targets that can be observed by radar [7,8]. While operational radar data (left image in Animation 1) show the temporal evolution of a storm at 5-min intervals, high-temporal-resolution data (right image in Animation 1) can provide more detail, as demonstrated in the time evolution at 30-s intervals. Because the advection vector updates by calculating for a period of volume scan interval [1], a storm in the high-temporal-resolution data do not move smoothly (such as a jumping downward movement shown in the right image in Animation 1).  The left image of Animation 2 shows observational radar data with 12 elevation angles before elevation interpolation from 1235 LST to 1239 LST; the right image shows 0.1 high-spatial-resolution radar data with 97 elevation angles at 1238:30 LST.

Implementation of three-dimensional storm information
Using the high spatio-temporal resolution data, a three-dimensional constant-altitude planposition-indicator (3D CAPPI) was created at a resolution of 250 Â 250 Â 250 m. The 3D CAPPI described the evolution of the storm at various angles. Investigating the evolution of a storm from various angles is useful for understanding storm structure, development, and movement (Animation 3e6 of Appendix A).