The MU radar at Shigaraki in Shiga prefecture, Japan (34.85N, 136.11E, 385 MSL) has been operated in the special observation mode of meteor since May 1990.
A Doppler beam Swinging (DBS) technique is used in normal MST radar having a pencil-like narrow beam to observe wind profiles, but not used in meteor observation mode because it is impossible to determine the arrival angle of each meteor echo.
In the MU radar, in addition to the pencil-like beam pattern, a doughnut-like radiation pattern is also designed and used by controlling the phase of the radiowave transmitter from each (Yagi) antenna, and is possible to detect meteor echoes widely distributed in zenith angle as large as 50 degrees. Besides a doughnut-like pattern, a broad beam pattern equivalent to a single Yagi is also used.
The interferometer is constructed by connecting four receiver (after 2004, 25 receiver) channels. The arrival angle of meteor echo can be determined by any combination of three receivers out of the four. We can estimate four independent arrival angles for a single echo. Their average is used as final arrival angle.
| IPP: | 1.95 ms |
| Range resolution: | 0.9 km (76.0-247.9 km) |
| Number of coherent integrations: | 4 |
Horizontal wind data and number of meteors in the mesosphere and lower thermosphere (70-110 km) in text, netCDF and gif (time-height plot) format can be browsed and downloaded here.
The horizontal wind data are calculated from the original observation (MU meteor wind observation) data with a weighting function. They are stored in files named
| W(year)(month)(day).(resolution).(ext) | for 1-day data |
| W(year)(month).(resolution).(ext) | for 1-month data |
| W(year).(resolution).(ext) | for 1-year data (only Time-height plot) |
| (resolution) = h1t60min00, h1t60min30, h2t60min00 and h2t60min30, (ext) = txt, nc, gif | |
The "(resolution)" represents a weighting function. For example, the h1t60 means weighted average with Gaussian factors over +/-1 km in height and +/-60 minutes in time. The min00 shows that the center of the Gaussian window corresponds to 00 minute of every hour. The intervals of the wind data are every 1 km and 60 minutes.
If you want to know more information of this data, please refer to the readme file and access the metadata in each data.
2000/10/20-26, 2001/3/23-41, 2001/7/8-15:
The number of meteors during these periods shows a regular variation with an interval of 2 hours. This variation is due to alternate meteor observations (30 min) and IS observations (1 hour).
2004:
The wind data in 2004 are not available due to the problem of the MU radar interferometer.
2006/4/30-:
The sensitivity of the MU radar was significantly enhanced because of the change of the meteor observation mode from 4 to 25 channels after April 2006, and the number of observed meteor trails increased. For this reason, the color range of gif (display) data was also changed after April 2006 (for example, from 5-55 to 50-550 for the meteor trail number).
This data has been registered in IUGONET (Inter-university Upper atmosphere Global Observation NETwork)
metadata database. The IUGONET metadata database will be of great help to researchers in efficiently
finding and obtaining ground-based observation data spread over the institutes/universities.
Click and visit to the IUGONET website.
IUGONET also prepared the data analysis software suite (UDAS) for the upper atmospheric observation data.
If you install the UDAS, you can easily access, download, visualize and analyze the MU mesosphere observation
data through the Internet. Please click and try to use the UDAS.
| Text: | Readme(English, Japanese), | Release Note(English, Japanese) |
| NetCDF: | Readme(English, Japanese), | Release Note(English, Japanese) |
| GIF: | Readme(English, Japanese), | Release Note(English, Japanese) |