The Recent Climatic Characteristic and Change in the Republic of Korea based on the New Normals (19912020)

Based on the new climate normals (1991 similar to 2020), annual mean, maximum and minimum temperature is 12.5 degrees C, 18.2 degrees C, and 7.7 degrees C, respectively while annual precipitation is 1,331.7 mm, the annual mean wind speed is 2.0 m s(-1), and the relative humidity is 67.8% in the Republic of Korea. Compared to 1981 similar to 2010 normal, annual mean temperature increased by 0.2 degrees C, maximum and minimum temperatures increased by 0.3 degrees C, while the amount of precipitation (0.7%) and relative humidity (1.1%) decreased. There was no distinct change in annual mean wind speed. The spatial range of the annual mean temperature in the new normals is large from 7.1 to 16.9 degrees C. Annual precipitation showed a high regional variability, ranging from 787.3 to 2,030.0 mm. The annual mean relative humidity decreased at most weather stations due to the rise in temperature, and the annual mean wind speed did not show any distinct difference between the new and old normals. With the addition of a warmer decade (2011 similar to 2020), temperatures all increased consistently and in particular, the increase in the maximum temperature, which had not significantly changed in previous decades, was evident. The increasing trend of annual and summer precipitation by the 2010s has disappeared in the new normals. Among extreme climate indices, MxT30 (Daily maximum temperature >= 33 degrees C days), MnT25 (Daily minimum temperature >= 25 degrees C days), and PH30 (1 hour maximum precipitation >= 30 mm days) increased while MnT-10 (Daily minimum temperature < -10 degrees C days) and W13.9 (Daily maximum wind speed >= 13.9 m/s days) decreased at a statistically significant level. It is thought that a detailed study on the different trends of climate elements and extreme climate indices by region should be conducted in the future.