English

A group from the U.S. National Oceanic and Atmospheric Administration studied the relationship between rainfall and global temperatures.

Explanation

The average annual rainfall in Japan is about two times the global average. Rain in Japan is concentrated in the rainy season, which usually lasts from late spring to early summer, and typhoon season, which usually lasts from July to October.

English

The group fed Japan’s precipitation data from 1977 to 2015 into an AI system. They then looked at “anomalous precipitation events” in which rain fell in very large volumes or over a wide area.

Explanation

In Japanese weather forecasts, you’ll often hear a modifier used before 「雨」 to describe what kind of rain is being talked about. For example, 「強い雨(tsuyoi ame)」 is “heavy rain,” and 「激しい雨(hageshii ame)」 is “intense rain.” Even if you have an umbrella, you’re likely to get drenched. If the forecaster says 「非常に激しい雨(hijoo ni hageshii ame)」 or 「猛烈な雨(mooretsu na ame)」, expect a “torrential downpour.” 「猛烈(mooretsu)」 means “violent” or “furious.”

English

In this context Chugoku refers not to the country of China, but to the westernmost region of Honshu, Japan’s main island.

Explanation

In 1977, there were 6.1 days of abnormal rainfall, but by 2015, the figure had approximately doubled. In the regions of Chugoku, Shikoku, Kyushu, Amami, and Okinawa, it had roughly tripled.

English

The group also used a supercomputer to study atmospheric conditions and ocean temperatures. They found that the increased frequency of abnormal rainfall is attributable to the rise in global temperatures caused by human activity.