Japan’s National Research Institute for Earth Science and Disaster Resilience (NIED) operates the world’s largest rainfall simulator in Tsukuba, Japan.
The facility consists of a warehouse-sized building which can be moved on rails over five experimental positions where structures and terrain to be studied can be installed. Rain with four different drop sizes can be generated, at a rate between 15 and 300 mm/hour, the latter close to the most intense rainfall ever reported on Earth.