South Korea redefines 'monsoon' to reflect climate change realities

South Korea's meteorological community has redefined the concept of the monsoon season after two years of discussion. The new academic definition frames the monsoon season not by rainfall, but by atmospheric conditions conducive to rain, reflecting climate change impacts.

The Korean Meteorological Society announced on the 5th that it had newly organized the academic definitions of 'monsoon,' 'monsoon season,' and 'monsoon rain.' This revision incorporates input from experts and the Meteorological Administration's Monsoon Special Research Center.

Previously, the definition of monsoon faced controversy as it didn't align with various meteorological definitions. The start and end of monsoons were inconsistent, and the concept became ambiguous with periods of no rain during the monsoon or heavy downpours after the season ended.

The revised definitions are: 'monsoon' as 'a phenomenon or weather where it rains for several consecutive days during summer'; 'monsoon season' as 'a period when conditions are favorable for heavy rain in the Korean Peninsula due to various mechanisms in summer'; and 'monsoon rain' as 'rain that falls during the monsoon season.'

A core aspect of the revision is viewing the monsoon season as a period when rain-conducive conditions form, rather than solely a period of rainfall. This means days with little or no rain are included within the monsoon season. The society also expanded the causes of monsoon rainfall to include low-pressure systems and convection, not just stationary fronts. However, rainfall from typhoons was excluded from monsoon rain. The Okhotsk Sea anticyclone, previously used in textbooks to explain monsoons, was removed due to uncertainty about its actual existence.

Regarding suggestions to use the term 'rainy season' (우기) instead of 'monsoon,' the society deemed it premature, with the prevailing opinion favoring an expanded use of the existing monsoon concept.