[Square] The Rainy Season Outside the City

Summer in the city is suffocating. In contrast, summer experienced outside the city creates a sense of freshness. It is only then that one realizes that the heat is a tempering process for bearing good fruit in the fall. Just a little outside the city, you can see rice seedlings standing upright and growing, enduring the scorching sun in water-filled rice paddies.

Rice, which must spend most of its time underwater from sprouting to transplanting until it is densely filled with grains, seems like an aquatic plant anew. How was rice farming, which requires so much water, possible in Korea?

Rice farming was likely possible in Korea because of the heavy rains during the 'Jangma season' (monsoon season). The rain during Jangma provides the absolutely necessary water during the young stage of rice. The rain during Jangma usually falls enough to submerge the slightly grown rice, and after the Jangma season, the young seedlings grow into mature plants by absorbing plenty of water. Thanks to the Jangma season that came unfailingly every summer, rice farming was possible. Thus, the Jangma season was a seasonal gateway that farmers had to pass through.

On the other hand, for most city dwellers, the Jangma season is perceived as an inconvenient season. The discomfort of commuting during Jangma, restrictions on outdoor activities, laundry that does not dry well, the damp weather, and intermittent heat waves make it a season with a high discomfort index.

Jong-seok Kim, Director of the Korea Meteorological Administration

However, recently, the appearance of the Jangma season has been changing. In the past, Jangma rain would continue for several days, then stop, and then rain again. Recently, there have been many days without rain for a long time during the Jangma season, to the extent that one questions whether it is really Jangma, leading to the emergence of a new term, 'dry Jangma.' The name Jangma season has become almost meaningless. That does not mean there is no stationary front causing the Jangma rain. The heavy rains that recently caused significant damage in Japan’s Kyushu region and southern China were due to the stationary front. In the past, the stationary front moved up and down north-south, distributing rain evenly. Recently, the stationary front hardly moves, causing certain areas to receive rainfall exceeding past statistics, resulting in massive human and property damage. In Korea, there have been many cases where the north-south difference in rainfall during the Jangma season is large, so even a slight movement of the stationary front during Jangma causes mixed fortunes.

The most concerning aspect of the changed Jangma season is that rain falls in the form of heavy localized downpours. Heavy localized downpours mean rain concentrated in one area. The CCTV footage from Japan’s Kyushu region showing water rising to waist height within 10 minutes and cars being swept away is an example of the terrifying nature of heavy localized downpours. During the Jangma season, sudden water surges cause rice paddy embankments to collapse, landslides to occur, or retaining walls to fall, resulting in property and human casualties. To make matters worse, the start and end of the Jangma season are no longer clear, making it unpredictable like a runaway horse. Korea’s Jangma season is changing significantly in the vortex of climate change. As global warming raises the Earth’s temperature, the atmosphere holds more water vapor, causing heavy rainfall in specific areas and resulting in damage. Therefore, in recent Jangma seasons, predicting where and how strong the rain will be is more important than how long the rain will last. Accordingly, the Korea Meteorological Administration is focusing its summer forecasts on heavy localized downpours to prevent damage in advance.

The Korea Meteorological Administration is also making great efforts to predict the changing climate and weather. Prioritizing the safety of the people, we hope that no damage will occur during this year’s Jangma season. Knowing that the Jangma season is no longer the same as in the past, the importance of meteorological information has grown even more. To bear this responsibility, the Korea Meteorological Administration keeps its office lights on 24 hours a day.

Kim Jong-seok, Administrator of the Korea Meteorological Administration