台風の進路予報を見ていると最近は「線状降水帯」という新しい言葉が盛んに出て来て危機を煽っている。 「線状降水帯」とは次々と発生する発達した雨雲（積乱雲）が列をなし数時間にわたってほぼ同じ地域を 通過または停滞することで作り出される長さ50～300ｋｍ程度、幅20～50ｋｍ程度の線状に伸びる強い 降水域を言い、その地域に土砂崩れや洪水などを齎す可能性が高い。これはＴＶやパソコンなどの映像技術が発達した結果、新たな情報表現テクノロジーであろうと思われる。しかし、私は「線状降水帯」と言うものは大昔から存在した自然現象で、「地球温暖化」などによって新たに近年発生したものではないと思っている。

　琵琶湖から６Ｋｍほど東の我家の周辺は線状降水帯被害に見舞われたことがないので線状降水帯の発生しやすい地形がある様にも思われ、東側に４～５百メートルの高い山があるなどの要件が必要かなと考えられるが、ＴＶ映像を見ると海上にも発生しているから必要条件ではないだろう。今後、地上で必ず発生する場所があるかどうかを注視して見よう。

 

 

 

　When looking at typhoon path forecasts, the new term ''linear precipitation belt'' has recently come up frequently, aggravating the crisis. 　A "linear precipitation belt" is a region of about 50 to 300 km long and 20 to 50 km wide, created when developed rain clouds (cumulonimbus clouds) form one after another and pass or stay in the same area for several hours. 　It refers to an area of ​​strong rainfall that extends in a linear shape, and is likely to cause landslides and floods in the area. 　This seems to be a new information expression technology resulting from the development of video technology such as TVs and computers. 　However, I believe that ''linear precipitation belts'' are a natural phenomenon that has existed since ancient times, and are not something that has recently occurred due to ''global warming.''

　The area around my house, which is about 6 km east of Lake Biwa, has never been affected by linear rain belt damage, so it seems that there is a topography that is prone to linear rain belts, and there is a 4-5 hundred meter high mountain on the east side. 　I think it would be necessary to have a requirement that there is, but if you look at the TV footage, it also occurs at sea, so I don't think it's a necessary condition. 　In the future, we will keep an eye on whether there are any places on the ground where it will always occur.