The Japan Agency for Marine-Earth Science and Technology and a research group at Hokkaido University have discovered that the Kuroshio is concentrating the rapidly developing "bomb low pressure" near Japan.
Explosive cyclogenesis is a system in which the central pressure drops by 35 hectopascals (hPa) or more in one day at the latitude of Tokyo (1 degrees north latitude).It was known that the current occurs concentrated in the Kuroshio / Kuroshio basin, but it has not been clarified whether the Kuroshio / Kuroshio current is affecting the explosion low pressure system.
This time, we conducted an experiment on the presence or absence of the Kuroshio in a global atmospheric model using JAMSTEC's supercomputer "Earth Simulator" to investigate the effects of the Kuroshio and Kuroshio follow-on currents on the atmosphere.
As a result, when the Kuroshio / Kuroshio follow-on exists in January, the explosive cyclogenesis develops concentrated in the northwestern Pacific as in the observation, whereas when the Kuroshio-Kuroshio follow-on does not exist, the explosive cyclogenesis develops. It turns out that the area moves east.
In addition, it is the first time in the world that the concentrated development of a cyclone over the northwestern Pacific Ocean activates the north-south meandering of the jet stream on the northeastern Pacific Ocean downstream of it and affects the precipitation distribution near the west coast of North America and Hawaii. Indicated.
Furthermore, when the cyclone passes over the Kuroshio, the water vapor that evaporates from the Kuroshio is taken in, so that the amount of precipitation near the center of the cyclone increases and the heat (condensation heat) generated when the water vapor changes to rain is generated. It was revealed that a cyclone was rapidly developing as an energy source.
The results show a series of atmospheric responses and mechanisms in which the heat energy carried by the Kuroshio-Kuroshio sequel from the tropics to mid-latitudes determines the atmospheric circulation and precipitation distribution over the North Pacific through the development of a bomb depression. It is said to be a newly proposed epoch-making result.It is expected to have a great impact on future forecasts and climate model development.
