Research on the use of X-band radar
Research is under way on the use of...
1) the X-band multiparameter (MP) radar rain gauge network, for accurate real-time observations of snowfall, and
2) high-resolution snowfall data, for snow removal operations.
X-band MP radar has been installed to monitor localized torrential downpours, which have been increasing in Japan due to climate change.
The accurate, high-resolution, 24-hour observation of snowfall is to be realized nationwide through the use of rain gauge data from X-band MP radar supplemented by C-band MP radar.
The provision of data obtained by the X-band radar network
Information on current snowfall and short-term forecasts of snowfall is provided to road users and to other members of the public. This shows the nation-wide view window.
A visibility information system
In Japan, numerous cameras have been installed at the roadside to monitor the traffic and road conditions. When snowstorms occur, the images captured by these cameras are white and misty, with little contrast.
A visibility information collection and distribution system that uses roadside camera images is being developed. The static images taken by the cameras are classified into four levels of contrast that reproduce the visibility recognized by the naked eye.
To classify the images, a visibility classification algorithm is used. The basic idea is that when a high-contrast image is captured, the visibility is high, and when a low-contrast image is captured, the visibility is low.
Snowstorm images taken in the winter of 2015 to 2016 by 800 cameras installed on national highways in Hokkaido Prefecture were analyzed, to categorize the visibility into four levels.
For the first time in Japan, an analysis of the time series of changes in visibility level were able to quantitatively determine snowstorm conditions when weather radar and general meteorological measurement equipment were not.
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Patent jointly obtained by Hokkaido Development Engineering Center and Hokkaido University