5:15 PM - 6:45 PM
[HDS10-P07] Identification of Issues by Reviewing the Past Disaster Prevention Weather Information
- From the Viewpoint of Residents’ Behavior at Disaster -
Keywords:Disaster Prevention Weather Information, Time-space Granularity, Disaster Prevention Literacy
In recent years, the accuracy of weather forecasts has improved, and the variety of disaster-prevention weather information has increased in response to social expectations. In addition, some disaster prevention weather information is issued in technical terms, and the meaning of information (weather changes and reasons for the information issuing) is not always understood by all residents. In this research, we focus on the following three points and report on the current status and issues of disaster prevention weather information.
(1) Types of information and time-space granularity
Recently, the types of disaster prevention weather information have increased. Furthermore, the spatial granularity of those information has ranged from prefectural scale to 1 km scale, and temporal granularity of them has ranged from weekly scale to information updated every 5 minutes. These facts show that both temporal and spatial granularity have become finer due to meshing and higher resolution. Takenouchi et al. (2014) concluded that information users do not quantitatively understand natural phenomena over a wide area but qualitatively understand local phenomena that occur within an elementary school district, and based on the needs of users, it seems that higher resolution can be evaluated. On the other hand, Sekiya (2022) pointed out that higher resolution shortened the lead time until the occurrence of a disaster. Therefore, we examine the merits and demerits of the increase in the types of information and the improvement of the resolution of space-time granularity to the residents by investigating the time-series changes in the types of information, lead time, and granularity of the information released by the time of disaster occurrence in several landslide disaster case studies.
(2) Awareness and understanding
Several questionnaire surveys on awareness and understanding of disaster prevention weather information have been conducted by experts and local governments (Ushiyama, 2013; JMA, 2022; Hiroshima Prefecture, 2018). An analysis of questionnaires conducted nationwide since 2005 shows that the level of awareness tends to increase year by year, but the level of understanding has not changed much over the past 10 years, indicating that this is an issue inherent in the current disaster prevention weather information. We will conduct the same analysis for other types of information, such as heavy rainfall warnings and recordable short-time heavy rainfall information, to confirm if similar trends can be observed.
(3) Accuracy and Frequency
According to the Ministry of Land, Infrastructure, Transport and Tourism (2021), the nationwide landslide disaster warning information issued from 2009 to 2019 had 4.7% accuracy rate and 96.4% catch rate. On the other hand, the frequency of issuing weather information that triggers evacuation behavior can be evaluated by comparing it with the acceptable range in which residents consider evacuation to be feasible. According to a questionnaire survey conducted by the Japan Meteorological Agency (2022), about 23% of the total respondents answered that they could evacuate at least twice a year during typhoons and heavy rain, and about 20% answered that they could evacuate once a year. By comparing these results and the actual issuance of each disaster prevention information from the viewpoints of frequency and accuracy, we will investigate whether the actual issuance of disaster prevention weather information satisfies the needs of users and conduct a new evaluation.
We analyze and evaluate the three points described above, and report the results of our study on issues and solutions for appropriate issuance of disaster prevention weather information.
(1) Types of information and time-space granularity
Recently, the types of disaster prevention weather information have increased. Furthermore, the spatial granularity of those information has ranged from prefectural scale to 1 km scale, and temporal granularity of them has ranged from weekly scale to information updated every 5 minutes. These facts show that both temporal and spatial granularity have become finer due to meshing and higher resolution. Takenouchi et al. (2014) concluded that information users do not quantitatively understand natural phenomena over a wide area but qualitatively understand local phenomena that occur within an elementary school district, and based on the needs of users, it seems that higher resolution can be evaluated. On the other hand, Sekiya (2022) pointed out that higher resolution shortened the lead time until the occurrence of a disaster. Therefore, we examine the merits and demerits of the increase in the types of information and the improvement of the resolution of space-time granularity to the residents by investigating the time-series changes in the types of information, lead time, and granularity of the information released by the time of disaster occurrence in several landslide disaster case studies.
(2) Awareness and understanding
Several questionnaire surveys on awareness and understanding of disaster prevention weather information have been conducted by experts and local governments (Ushiyama, 2013; JMA, 2022; Hiroshima Prefecture, 2018). An analysis of questionnaires conducted nationwide since 2005 shows that the level of awareness tends to increase year by year, but the level of understanding has not changed much over the past 10 years, indicating that this is an issue inherent in the current disaster prevention weather information. We will conduct the same analysis for other types of information, such as heavy rainfall warnings and recordable short-time heavy rainfall information, to confirm if similar trends can be observed.
(3) Accuracy and Frequency
According to the Ministry of Land, Infrastructure, Transport and Tourism (2021), the nationwide landslide disaster warning information issued from 2009 to 2019 had 4.7% accuracy rate and 96.4% catch rate. On the other hand, the frequency of issuing weather information that triggers evacuation behavior can be evaluated by comparing it with the acceptable range in which residents consider evacuation to be feasible. According to a questionnaire survey conducted by the Japan Meteorological Agency (2022), about 23% of the total respondents answered that they could evacuate at least twice a year during typhoons and heavy rain, and about 20% answered that they could evacuate once a year. By comparing these results and the actual issuance of each disaster prevention information from the viewpoints of frequency and accuracy, we will investigate whether the actual issuance of disaster prevention weather information satisfies the needs of users and conduct a new evaluation.
We analyze and evaluate the three points described above, and report the results of our study on issues and solutions for appropriate issuance of disaster prevention weather information.