Journal of Natural Disaster Science, Volume 24, Number 2, 2002, pp43-49

An Internet-based Real-time Heavy Rainfall Display System
Motoyuki USHIYAMA* and Kaoru TAKRA***Disaster Control Research Center, Graduate School of Engineering, Tohoku University**Disaster Prevention Research Institute, Kyoto University(Received for 7. Oct., 2002)

ABSTRACTA new storm warning system, which can be accessed through the Internet and by cellular phones is described.
At the time of a heavy rainfall for disaster prevention, it is important that every resident understand how heavy isthat rainfall. A real-time heavy rainfall display system designed for all of Japan provides such information(http://www.disaster-i.net/rain/). In that system values for 1-hour precipitation, 24-hour accumulated precipitation, etc. are displayed at every observatory. Advantages are that not only the latest observations but differencesfrom the historical highest records can be seen. Almost all information is displayed by characters so that users
have easy access to the system even when the communication network is crowded. Access date for the six
months after the system opened shows that the average daily number of accesses of the top page was 306, and thelargest number 3078. The maximum number for daily access to all the pages was about 21,500. This is about 2%of the number obtained on the same day for a similar system operated by the Ministry of Land, Infrastructure andTransport (http://www.river.go.jp/).

1. INTRODUCTION
Various kinds of weather information now can be seen on theInternet. For example, the homepages of weather informationcompanies and the press provide so-called on-the-spot information such as current precipitation observations and data fromweather radar. Moreover, a traditional weather report (ex.
Fine , Rain ), a quantitative precipitation forecast, a rainfall
probability forecast, etc. also are seen on homepages. On-thespot information and forecast information about precipitation
are widely offered today not only to specialists but to the generalpublic.
When coping with a heavy rainfall disaster (e.g.; flooding,sediment disaster), these nowcast information and forecast
information. are not sufficient. For example, the following information is required: How much has it rained until now? , What is
the record high for the area? Concretely, this would be the 24hour accumulated precipitation, the highest precipitation at eachobservatory. Unfortunately this type of information is not foundon the Internet today.
Ushiyama (1999, 2001) has reported that the general publicdose not understand observation date (e.g., precipitation) and their
meanings well, even when given as disaster information. Not only
data supply but their explanations are required to overcome ignorance and avoid misunderstandings.
Access to the Internet by cellular phone (such as i-mode by
NTT DoCoMo Inc.) has spread rapidly Japan since 1999. The percent of household use in Japan as of February 2001 was estimatedas 46.5%, and the number of cellular phones in use at 28.4%(Internet Association, 2001). Internet browsing by cellular phone
is a promising method for information exchange at the time of aheavy rainfall disaster. Weather information pages for cellular
phones also are increasing, but so far do not contain informationthat is useful for disaster prevention.
We developed a real-time heavy rainfall display system
which can be accessed with Internet browsers and cellular phones.
This system aims to offer useful information for making judgment
and decisions at the time of heavy rainfall. We here describe theconcept and the construction technique of this system and examine
the system s effectiveness by analysing the access log date for six
months after it opened.
2.

OUTLINE OF THE SYSTEM

2.1 Basic development policies
The system was developed based on the following policies:
a. Data should be displayed in distribution maps (pictures) andnumber tables.
b. Accumulated precipitation (e.g., 2- and 24-hour) should be displayed.
c. The highest historical precipitation at each observatory should
be displayed to provide an easy comparison of the difference
between the historical high and latest observation values.
d. Almost all information should be displayed by characters forquick response.
e. The homepage of this system should be accessible using standard Web browsers without additional software.
f. The information recorded can be accessed and downloaded.
g. Data can be easily seen with a cellular phone (especially imode ).
h. Explanatory descriptions about the observation data are included for easy understanding.

KEY WORDS: disaster information, Internet, cellular phone, historical rainfall records, AMeDAS.

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M. USHIYAMA AND K. TAKARA

2.2 System composition(1) Outline
Data from the AMeDAS (Automated Meteorological Data
Acquisition Syetm) observatories operated by the Japan
Meteorological Agency (JMA) since 1979 are the basic data usedin our system. The AMeDAS has about 1300 observatories
through out Japan. It therefore is easy to receive real-time data,
and the positions, historical information on observatories are available, and past observation data are readily obtainable.
The system, composed of two Windows 2000 personal computers, uses MICOS, a weather information supply system provided by the Japan Weather Association (JWA). One computer isused as the MICOS receiver, the other as an open server for processing real-time heavy rainfall.
The MICOS usually is used to scan and print weather information with the aid of JWA software. In addition, text data of
weather information are saved in the MICOS receiver. Our Realtime Heavy Rainfall Display System makes use of the text datatransmitted from the MICOS receiver to the open server (Fig. 1).

Fig. 2(2) Data processing
Of the various kinds of weather information received by theFig. 1

Outline of the Real-time Heavy Rainfall Display System.

The top pages of system.

AN INTERNET-BASED REAL-TIME HEAVY RAINFALL DISPLAY SYSTEMMICOS system, AMeDAS data are processed in the open server.
The locations and highest historical precipitations at all the
AMeDAS observatories are based on Japan Meteorological
Agency (2000) information. The highest historical precipitation
records are consist of the highest data from 1979 to 1999. The system continuously compares the latest observation data with thehighest historical data.
Data processing and HTML file composition respectively are
executed by the awk and perl scripts. Distribution maps are
created by GMT , GIS software developed by the University of
Hawaii (http://gmt.soest.hawaii.edu/). The GMT output file is a
PS (Post Script) file which cannot be viewed on popular Web
browsers. The PS file therefore is transformed into a PNG(Portable Network Graphics) picture file by gswin32. exe that isincluded in Ghostscript , a popular PS file browser. For i-mode
phones, the PS file is transformed into a small-size GIF picture filefrom PNG by the so-called retouch software Dicre Image Touch(http://www.dicre.com/).
AMeDAS observation data are distributed every hour 5 minutes after the hour but often are delayed. Our system therefore
processes data every hour 15 minutes after the hour. The automatic running of this system is controlled by Task , pre-installed in
Windows 2000.

Fig. 345

2.3 Contents(1) Top pageThe top page of this system is shown in Fig. 2 (http://www.
disaster-i.net/rain/). There are two versions: the normal version (inEnglish and in Japanese) and the i-mode version (in Japaneseonly). The i-mode version pages also can be seen with theInternet accessible cellular phone of J-Phone Inc. (so-called JSky).
(2) Precipitation distribution map
This system creates 1-, 2- and 24-hour precipitation distribution maps for the latest data, as well as providing certain explanations for better understanding. When a 1-hour precipitation of
50mm or more, or the 24-hour precipitation of 100mm or more
occurs, it is shown in a table with the observatory name and thehighest precipitation at that observatory (Fig.3).
(3) Renewal of the location map of the highest precipitation
When the latest 1- or 24-hour precipitation at an observatory
surpasses the historical high from 1979 to 1999, a red-coloredasterisk is placed on the map to show the location of the observatory (Fig. 4). It is difficult for a general user to understand the danger of such precipitation based on a simple precipitation distribu-

The page for the 24-hour precipitation.

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M. USHIYAMA AND K. TAKARA

Fig. 4

Page showing observatories with the highest historical amount of precipitation.

tion map, where as this figure readily indicates the area in which
the latest precipitation exceeded the highest rainfall recorded in thelast 20 years. The figure is expected to help users understand how
dangerous the rainfall is.

created. Moreover, to help users to understand them, explanationof the intensity of precipitation also is provided based on information from the Department of Forecast, Japan Meteorological
Agency (2000).

(4) Map archive
As all the precipitation distribution maps created by this system are stored, a user can obtain them freely from the archive
through the Internet. FTP access however is not permitted for reasons of security. The map file name has ten digits indicating theyear, month, day, and hour. Map files are saved in the monthsub-directory in the kind directory. Users can reach the required
maps by going through the directories.

(6) Observatory pages
Data display pages for each observatory also are made forthese distribution maps. These pages are used in both the normal
and i-mode versions. A user can search for a required observatory from the top page, as shown in Fig.5, or from the Prefecturename and observatory list pages. Each observatory page consistsof characters without image data for the convenience of cellular
phone access and consideration of the busy traffic on the network.
A simple graph display method with characters is used foreasy understanding. This a creates a simple bar graph using the= character, called a Text graph or Character graph ; e.g. for
24-hour precipitation, one = corresponds to 25 mm. This graphis displayed in the observatories list for each prefecture, therefore(5) Precipitation distribution map for the i-mode phone
The i-mode cellular phone cannot see normal large-size
maps such as those of 385x432 pixels, therefore small-size precipitation distribution maps (96x80 pixels) for portions of Japan areAN INTERNET-BASED REAL-TIME HEAVY RAINFALL DISPLAY SYSTEM

Fig. 547

Outline of observatory pages（i-mode version）.

it is easy to find the rain areas in a prefecture. Each observatory
page includes the observatory code, name, address and elevation,
as well as the latest hourly and 24-hour precipitations followed by
the series of previous 12 hourly precipitations. It also gives thehighest historical hourly and 24-hour precipitations in a text graphand the 3 highest past records.
Even when the name of the AMeDAS observatory is the sameas a city or town name, it may be located several kilometers fromthe central part of that city or town (Ushiyama, 1999). Often the
difference in hourly precipitation between places several kilometers apart is 20 to 30mm or more, therefore location information isimportant. Few homepages show the addresses of AMeDAS
observatories, where as this system does.
(7) Heavy rainfall warning e-mail system
This function automatically informs users of the occurrence ofheavy rainfall by e-mail system, when a value exceeding the specified precipitation (e.g. 50 mm for 2-hours of precipitation) is
recorded. Information transmission is kept to a minimum for cel-lular phone users. This e-mailed information gives the prefecture
and observatory names in 2 Japanese characters, the 1-, 2- and 24hour precipitations, and the time. Users can access detailed information by clicking the URL, given below. About 180 persons
have now registered as users of this e-mail system.
3.
3.1

CURRENT USE OF THIS SYSTEM

Access situation
The system was implemented between October 2000 andMarch 2001 (Table 1). Figure 6 shows the day-to-day access its
top pages since April 1, 2001. Note that access to the i-mode
version pages from personal computers is not included.
Access appears to be increasing for both versions top pages.
The average number of accesses from Apr. 12, 2001 to Sep. 24
was 306 per day for the normal version and 75 per day for the imode one.
When heavy rainfall occurred, access increased rapidly. The
maximum access to the normal version top page on Aug. 21, 2001,

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M. USHIYAMA AND K. TAKARA
Table 1. Timetale of system development.

normal and i-mode versions. This means that many people havea greater interest in the latest 1-hour precipitation than in accumulated precipitation . Access to the observatory which surpassed the highest record page was 29% of that to the 1-hour precipitation page. This function, a special feature of the system, provides users with information on the record-breaking rainfall eventthat occurred and its location.
4. CONCLUSIONS

Fig. 6

Top page accesses from April 1 to September 24，2001.

was 3078 hits, followed by 2001 hits the next day. On those days
Typhoon No.0111 passed through the Japanese archipelago.
When Typhoon No.0115 passed through east Japan on Sep.11 and12, the respective of accesses to the normal version top page were1986 and 1690.
There tend to fewer accesses to the i-mode version than to
the normal version. On Sep. 11, 2001 the maximum number ofaccesses to the i-mode version was 1228.
3.2

Characteristics of access information
The access situation for pages of this system is shown in
Fig.7. Except for top pages the 1-hour precipitation page was themost often accessed. For the 24-hour precipitation page the value
was about half that for the 1-hour precipitation page for both the

An Internet-based, real-time heavy rainfall display system
which can be viewed with Internet browsers and cellular phones
was developed. It is composed of certain existent tools (programs)
and original script files available on Windows 2000. One important feature is that the highest historical precipitation and the present precipitation are shown on the same page. This is useful inthat users can easily compare the present precipitation intensitywith past heavy rainfall and knew the seriousness of the present
one. Another important feature is that the system is very simple.
Because almost all the pieces of information are displayed as characters, users can readily gain access from cellular phones.
The Real-time Heavy Rainfall Display System , opened in
April 2001, has attracted attention from society. The number ofaccesses to it shows a favorable increase. The system is accessible
from various computers and cellular phones, as shown in 3.1.
The maximum number of accesses to all the pages of this system was about 21,500 on Sep. 11, 2001, and about 21,000 on Aug.
21. The number of accesses to a similar governmental system,
which opened after ours on Sep. 11, the Disaster Prevention
Information on Rivers (http://www.river.go.jp/) operated by the
Ministry of Land, Infrastructure and Transport was about
1,000,000 (Turuta et al., 2001). Because this governmental system
has greater content, these numbers cannot be compared directly,
but our system has drawn the attention of many people even,though it was developed by very few people.
The system now is linked to at least 50 homepages. It wasannounced as king of this week in the Oct. 26, 2001 issue ofGiga Choice (http://www.gigahz.net/choice/) which evaluates
i-mode version homepages throughout Japan. The system also
was introduced in other evaluation sites; magazines for i-mode
users and newspapers. As evaluated by society, it has alreadyproved practical. Our Real-time Heavy Rainfall Display System
is a pioneering work and several similar systems follow the ideasof that system.
Access log analysis showed that the number of accesses on apeak day is several dozens of times that on a normal day. This
proves that a simple design is needed for this type of information

AN INTERNET-BASED REAL-TIME HEAVY RAINFALL DISPLAY SYSTEM

Fig.7

49

Number of accesses to the main iformation pages from April 1 to September 24，2001.

system. In contrast, it can show more kinds of information.
Development of a simple, intelligent system in the near future is
expected to make the system more tractable and practical.
Not only accumulated precipitation but the effective precipitation (e.g., Antecedent Precipitation Index) is important in terms of
sediment disasters. This type of rainfall information system also is
expected to useful for sediment disaster prevention and mitigation.
ACKNOWLEDGMENTS
This system was created by joint research between the Japan
Weather Association (JWA) Kansai Branch Office and the Flood
Disaster Lab., DPRI, Kyoto University. Special thanks are owed
to Tomohisa MANAKA, JWA for his technical support andadvice, as well as to Dr. Yutaka ICHIKAWA, Faculty ofEngineering, Kyoto University and Dr. Daichi NAKAYAMA,
Faculty of Science, Tokyo Metropolitan University for their valuable advice. This research was supported in part by a Grant fromthe SABO Technical Center and a Grand-in-Aid for Scientific
Research (B)(1), 12556023 (PI: Prof. Shigeru OGAWA, Kyusyu
Univ.).
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