Heavy Rainfall in July "Abnormal weather continued over a wide area" Meteorological Agency Study Group

Heavy rain in July "extremely long and unusual weather" JMA meeting 20:47, August 20

Regarding the series of heavy rains in the last month, the Japan Meteorological Agency's study group pointed out, "It was an abnormal weather in terms of heavy rain that continued over a wide area." In addition, he said, "We need to be prepared for typhoons, etc., keeping in mind that extreme phenomena will continue to occur due to the effects of global warming."

The Meteorological Agency's "Extreme Meteorological Analysis Study Group" made by experts analyzed a series of heavy rainfall last month.

One of the factors was that the sea surface temperature of the Indian Ocean was higher than normal, which means that the sea surface temperature was high especially in the western Indian Ocean and the activity of cumulonimbus was active. is.

Due to this effect, cumulonimbus clouds around the Philippines became inactive, causing the Pacific Ocean high pressure to extend to the southwest of Japan rather than the normal year, weakening the upward extension of the Tibetan high pressure to the north, and the westerly wind meandering southward. It was that there was.

For this reason, the Baiu front continued to stagnate near Japan without moving northward, causing water vapor from the west along the front and vapor from the south around the Pacific high pressure to gather in Japan, causing a record heavy rain. I am analyzing.

On the other hand, from the beginning of this month, cumulonimbus activity in the vicinity of the Philippines has increased and the Pacific high has expanded to Japan. It has brought about the heat wave of, and pointed out that this trend is expected to continue until the beginning of next month.

Professor Nakamura, Professor of the University of Tokyo, who is the chairman of the study group, said, "It is reasonable to consider it to be abnormal weather from the viewpoint of the wide area and sustainability of heavy rainfall. This time too, the amount of water vapor increased due to the effects of global warming. We need to be prepared for typhoons and other events, keeping in mind that extreme phenomena are likely to occur in the future."