Typhoon No. 19 Record heavy rainfall in "Atmospheric River" where a large amount of water vapor flows

Typhoon 19: Record heavy rainfall at `` Atmospheric River '' where a lot of water vapor flows in December 24 1:36

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In October, Typhoon No. 19 caused enormous damage to eastern Japan and Tohoku. The record-breaking downpour was found to have been caused by a large influx of water vapor, an "atmospheric river" formed over the sky. Experts warn that global warming is increasing and that heavy rain disasters like never before could be repeated.

Why did Typhoon 19 bring record-breaking heavy rain? Prof. Kazuhisa Tsuboki of Nagoya University, familiar with the mechanism of the typhoon, made an analysis based on the distribution and simulation of the amount of water vapor captured by satellites.

Then, from October 10 to 12 until the typhoon approached and landed, we found that there was a huge band of water vapor flowing over the Pacific Ocean on the east side of the typhoon.

This was called the "River of the Atmosphere". As of the night of November 11, it was about 500 km wide and 2,000 km north-south from the east of the Ogasawara Islands to the sea east of the Kanto and Izu Islands.

The amount of water vapor flowing per second is about 500,000 to 1 million tons, which is equivalent to two to three times the amount of water flowing by the Amazon River in South America.

Cumulonimbus cloud develops in "Atmospheric River"

Water vapor from this "atmospheric river" was brought to land one after another under the influence of the wind of the typhoon, hitting and converging on the mountainous area and developing cumulonimbus clouds, causing heavy rain before the typhoon approached.

Furthermore, the typhoon's main body followed by rain clouds, which caused record heavy rains in eastern Japan and Tohoku.

The "atmospheric river" was also formed four years ago during the "Kanto-Tohoku Heavy Rain", which at that time led to the development of a zonal cumulonimbus called a "linear precipitation zone".

Global warming could lead to heavy rain disaster

Professor Tsuboki does not clearly understand why the "atmospheric river" was created, but believes that the effect of the rising seawater temperature in the south of Japan is due to the fact that water vapor is mainly brought by seawater. .

On top of that, it is warned that global warming is expected to continue in the future, and that "atmospheric rivers" are likely to be formed, which may cause repeated heavy rain disasters that have never been experienced before. You.

In addition, Professor Tsuboki points out that not only Typhoon 19 but also Typhoon No. 15, which caused damage from storms mainly in Chiba Prefecture, will increase the number of typhoons approaching and landing with strong power as global warming advances. doing.

Professor Tsuboki said, "We are entering an era of storms and heavy rains that we have never experienced before. We think that there is no year without a severe disaster that we could not respond to the disaster prevention measures that we had done in the past. You should seriously consider measures based on future predictions. "