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During the summer of 2011, all Korean citizens heard and experienced the extreme weather conditions caused by climate change. Last summer, the average precipitation rate for 3 months was 1300mm nationwide. In the central region, nearly 1315mm of rain was poured. Calculated from the average, it was found that rain for the whole year was made to come within just three months. Seoul, the capital of Korea was no exception. During the torrential rainy season from June 22 to July 17, 800mm of rain fell in Seoul. In particular, over 1000mm of rain poured in Yangpyeong of Gyeonggi-do near the Han River. Over 70 percent of annual precipitation was recorded to be rained at once. Extreme weather condition created by the climate change was quite formidable.
Then in late July when the rainy season was ended, the heavy rain fall again in the central region including Seoul. On July 27, 18 people lost their precious lives in the landslide of Woomyeon Mountain in Seoul. The lowlands in Gangnam, the heart of Seoul were flooded with rain. Enormous property damage was found as well as the heavy traffic due to submerged roads. It has become easy to say that the weather in Korea is now changing to be subtropical. This extreme change was analyzed to be due to global warming which has been gradually progressed over the past 10 years. Korea is also prominently experiencing changes in the summer weather. As a person who has to predict a long-term climate based on the accumulated data, it is bound to be perceived as annoying.
Once, the rainy season used to be called as the ‘Fifth Season.’
It was because the pattern had been repeated, in which the boring rainy season continued until July and the extremely hot weather followed after in August. This pattern had been shown for thousands of years. However, today there is no distinguishable monsoon season anymore. It is raining enough to express that the rainy season starts in June and lasts until August. Also if you look at the characteristics in the summer of 2011, you can see that the rainy season had started early and ended early. There was no distinct changes were found in Jeju Provence and southern region having a month long rainy season. However, rainy period of the central region was a week shorter than the usual.
In addition, the rain front used to move from north to south, up and down repeatedly during the rainy season. Then there used to be a lull as a resting period. However, it rained continuously without breaks in 2011. In case of Seoul, a new record was set by 9 days of continuous rain in June. It rains under the influence of monsoon front in June and July, but regional torrential rainfall appears in August because of the continued instability in the atmosphere. Because of this, the extraordinary phenomenon has been found that the precipitation of August exceeds that of July in the past 10 years.
Yet it is necessary to be aware of storm movements that have been changed. Usually, most of the hurricanes heading to the peninsula make a turn in the middle to the east direction moving to Japan. However, two hurricanes that came near the peninsula until last summer, No. 5 Typhoon Maeari and No.9 Typhoon Muyipa have unusually entered the way along the West Sea.
Another change was that those two typhoons affected the country giving a lot of rain. While the number of typhoons that occur on the Pacific Ocean decreased, the intensity of them directly or indirectly affecting the peninsula increased. This degree of intensity was not usually found before.
What we have experienced in an extreme form of precipitation last summer could become the usual phenomenon not a bizarre occurrence. Even today with brilliant civilization, the risk of extreme weather and climate change is still near us. However, in case of Korea, no damage was found by the concentrated rainfalls in 2011, which was to be an extreme case in 100 years. The reason why the damage was significantly reduced compared to the past despite the heavy rains was because of the dredging effects and the advanced meteorological system to prevent disaster in the Four Major Rivers Restoration Project.
Recently, the Meteorological Office is jointly utilizing the data of 25 weather radar units that are owned by the Ministry of Land, Transport, and Maritime Affairs and the National Defense.
Starting in 2011, the efforts are being made to increase the accuracy of precipitation forecasts by taking advantage of full clairvoyance weather satellites and supercomputers.
The Four Major Rivers Restoration Project will reduce flood damage even with annually increasing summer precipitation and the formidable rainfall. The reason there was no damage in the areas usually prone to floods of the four rivers was because of the increased water holding capacity of rivers. We have now entered into the era where new weather records are created each year due to climate change. The best prevention measures utilizing scientific information produced by the latest technology will protect lives and property of citizens.