10:15 AM - 10:30 AM
[ACG49-06] Increase in summer precipitation and air temperature in the Tokai district due to the Kuroshio Large Meander
Keywords:Kuroshio Large Meander, Precipitation, Japan's Climate, Marine Heatwave
Since August 2017, the Kuroshio has taken a large meander path state and has persisted, breaking the longest record in the history of observations. Accompanying this large meander path, significant coastal warming has been observed off the Tokai district, leading to the occurrence of prolonged marine heatwaves. This warming enhances evaporation from the sea surface, increasing atmospheric water vapor, which is expected to influence precipitation. This study investigates the characteristics of coastal warming due to the Kuroshio large meander and its impact on the Japan’s climate, especially in summer when the monsoonal southerly winds prevail.
First, satellite observation data were analyzed to examine the sea surface temperature (SST) during the current large meander period. The results show that SST off the Tokai district increased by about 3°C compared to the climatological mean, with a maximum increase of about 5°C. This warming is attributed to the Kuroshio large meander, most of which is classified as a marine heatwave. To evaluate the impact of this coastal warming on climate, numerical experiments were conducted using a regional atmospheric model developed by the Japan Meteorological Agency/Meteorological Research Institute. The results reveal that the coastal warming off the Tokai district strengthens monsoonal southerly winds, enhances water vapor transport, destabilizes the atmosphere, and increase precipitation by a factor of up to 1.5. Furthermore, the increase in water vapor causes a localized greenhouse effect, increasing temperatures in the Tokai district by approximately 1°C.
Furthermore, recent climate model simulations based on future climate scenarios suggest that SST off the Tokai district is likely to indicates by 2°C by 2050. In addition, numerical experiments assuming a 5°C SST increase by 2050 indicated that precipitation could double.
These findings will contribute to a better understanding of how changes in the Kuroshio path influence the Japan’s climate and improve weather forecasting and disaster preparedness.
First, satellite observation data were analyzed to examine the sea surface temperature (SST) during the current large meander period. The results show that SST off the Tokai district increased by about 3°C compared to the climatological mean, with a maximum increase of about 5°C. This warming is attributed to the Kuroshio large meander, most of which is classified as a marine heatwave. To evaluate the impact of this coastal warming on climate, numerical experiments were conducted using a regional atmospheric model developed by the Japan Meteorological Agency/Meteorological Research Institute. The results reveal that the coastal warming off the Tokai district strengthens monsoonal southerly winds, enhances water vapor transport, destabilizes the atmosphere, and increase precipitation by a factor of up to 1.5. Furthermore, the increase in water vapor causes a localized greenhouse effect, increasing temperatures in the Tokai district by approximately 1°C.
Furthermore, recent climate model simulations based on future climate scenarios suggest that SST off the Tokai district is likely to indicates by 2°C by 2050. In addition, numerical experiments assuming a 5°C SST increase by 2050 indicated that precipitation could double.
These findings will contribute to a better understanding of how changes in the Kuroshio path influence the Japan’s climate and improve weather forecasting and disaster preparedness.