Japan`s volcanic ash could affect Korea in summer

Korea has suffered no damage from ash emitted from recent volcanic activity in Japan, but could suffer damage if the eruptions continue through the summer.

Regions in southern Kyushu are undergoing robust volcanic activity. Mount Shinmoedake (1,421 meters above sea level) started erupting from Jan. 27, while Mount Minamidake (1,060 meters) began doing so Monday.

Kagoshima Prefecture is suffering massive damage due to ash from erupting volcanoes, but the Korean Peninsula, which is about 500 kilometers to the northeast, has seen no damage thus far. Most volcanic ash is moving toward the Pacific Ocean southeast of Japan fanned by northern and northwest winds or seasonal winds of the winter.

If volcanic eruptions continue through summer, however, chances are high that the Korean Peninsula will suffer damage from volcanic ash as well.

Kim Seung-beom, researcher at the National Institute of Meteorological Research, said, "If two conditions are met in the summer season, when the direction of seasonal winds changes, ash emitted from Kyushu volcanoes could reach the Korean Peninsula."

The two conditions are "direction of the wind (arrangement of atmospheric pressure)" and "emission height of volcanic eruptions." Northeast Asia, which encompasses the Korean Peninsula and the Japanese archipelago, has southern or southeast winds in the summer because strong high atmospheric pressure is formed in the North Pacific.

If this atmospheric pressure is created in a faraway location of the East Sea, winds come to blow through Kyushu along the Japanese archipelago and before passing through the Korean Peninsula. If volcanoes continue to emit ash through that period, ash will fall onto the peninsula fanned by the wind.

Also important is the emission height of volcanic ash. If volcanic ash reaches only a low altitude of one to two kilometers into the sky, chances are high they fall onto sea before reaching the Korean Peninsula.

If they reach five kilometers or higher, most of the ash will stream to the east fanned by the prevailing westerlies that form strong winds in middle altitudes, rather than seasonal winds, and thus will have a limited impact on the Korean Peninsula.

Kim said, "If the emission height is three to four kilometers, volcanic ash is forecast to reach the Korean Peninsula in the largest quantity," adding, "We will from now on calculate the exact conditions for wind direction and emission height through simulations."

The emission height of ash from Japanese volcanoes sometimes reaches two to three kilometers, and thus ash can lightly affect the Korean Peninsula.

If volcanic ash streams into Korea in large volumes, massive damage could ensue. Oh Yong-hae, director of the seismic surveillance division at the Korea Meteorological Administration, said, "In the past, volcanic ash blanketed crops to spawn damage, but recently they`ve cause malfunctions of medical equipment or precision control devices and hindered aircraft operation."

"Notably, if fine dust levels temporarily rise in areas with many high-tech industry complexes such as semiconductors, this can momentarily increase product defect ratios or result in temporary suspension of plant operations."

jermes@donga.com