VII. International Activity

3. Tokyo Volcanic Ash Advisory Centre

Volcanic activities may not only cause disaster against people living around volcanoes, but also damage aircraft by volcanic ash. As many accidents in which aircraft encounter volcanic ash have occurred since 1980's, the International Civil Aviation Organization (ICAO), cooperated closely with the World Meteorological Organization (WMO), recommended the establishment of Volcanic Ash Advisory Centres (VAACs). The latter provide the advisory information on volcanic ash trajectories to civil aviation authorities and airlines through the Meteorological Watch Offices (MWOs).

The Japan Meteorological Agency (JMA) was designated by ICAO as one of the VAACs responsible for the Asia and Pacific regions. Responding to the request, JMA established the Tokyo Volcanic Ash Advisory Centre (Tokyo VAAC) in the Tokyo Aviation Weather Service Center, and its routine operation started in March 1997. The area which the Tokyo VAAC has responsibility extends from 10 oN to 60oN, and 100 oE to 180oE, adjacent to the responsible areas of the Anchorage, Darwin and Washington VAACs (Fig. 33). The Tokyo VAAC provides volcanic ash advisories to MWOs in its responsible area and also to other VAACs when the ash may affect airline routes.

Acquisition of Volcanic Eruption Information

The emergency operation of the Tokyo VAAC is generated by the following observations and reports;

1) Detection of volcanic ash cloud in satellite imagery (GMS-5 and NOAA). Satellite imagery is routinely inspected by the Tokyo VAAC to find out ash cloud, and precisely examined immediately after receipt of eruption information.

2) Pilot reports on volcanic ash clouds associated with eruptions of both domestic and foreign volcanoes, which are transmitted to JMA.

3) Volcanic Activity Reports for foreign volcanic eruptions, transmitted to JMA via the respective Meteorological Watch Offices

4) Reports on volcanic activities in Japan, from JMA's observatories

5) Transmitted reports on volcanic activities, from the foreign volcano observatories

6) Mass media news

Since JMA conducts both the aviation weather service and volcanological observation, the volcanic activity reports issued from the volcano observatories can be promptly transmitted to the Tokyo VAAC.

The Tokyo VAAC uses mainly satellite imagery of Geostationary Meteorological Satellite of JMA (GMS-5) to detect, discriminate and trace ash clouds. Two independent infrared images from GMS-5 are very effective to identify ash clouds from meteorological clouds.

Issuance and Dissemination of Volcanic Ash Advisory

In immediate response to ash clouds, the Tokyo VAAC issues Volcanic Ash Advisories (VAAs) with the ICAO format. These advisories are followed by issuance of Significant Meteorological Statements (SIGMETs) from WMOs. The VAAs contain the following information;

1. Occurrence of volcanic eruption

2. Ash cloud detected in satellite imagery

3. Extent and movement of ash cloud tracked by using imagery of GMS-5 and NOAA satellite

4. Successive information on volcanic activity

5. Outlook on dispersion and trajectory of ash cloud with the numerical model

The VAAs are transmitted to Meteorological Watch Offices, VAACs, major airlines, Japan Civil Aviation Bureau, Aviation Weather Service Centers and Aviation Weather Stations of JMA. Information flow for VAAs is shown in Fig. 34.

The VAAs from the Tokyo VAAC are basically issued when ash clouds go up to a height of 5 km and more above sea level, or 3 km and more above the craters. The advisories are also issued basically every 6 hours while the ash clouds are observed in satellite imagery.

The Tokyo VAAC has issued about 60 VAAs for volcanic eruptions mainly in Japan and Kamchatka by the end of 1998.

(Naoya Mikami)

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