2:15 PM - 2:30 PM
[MIS12-23] Global climate zones and East Asian monsoon climate during the last glacial/global warming period as estimated from global climate model output
Keywords:Global Climate Model (GCM), Last Glacial Maximum (LGM), Global warming, Unsupervised machine learning clustering
Using the output of MIROC-ES2L, a global climate model (GCM) developed by the University of Tokyo, which is participating in Phase 6 of the Coupled Model Intercomparison Project for the Atmosphere-Ocean Intercomparison Project (CMIP6), a climate zone analysis of the simulation output during the last glacial period (LGM) and future global warming is conducted.
Unsupervised machine learning clustering, the k-means++ method, is applied to surface temperature, precipitation, east-west and north-south wind data, and the spatial distribution of the classified data is used to determine global climate zones and East Asian monsoon climate zones.
From the LGM to the present, climate zones change significantly in the Northern Hemisphere high latitudes. In particular, the cold zone area is reduced by about 37% due to the loss of ice sheets that existed in the LGM. With global warming, the tropics and deserts expand by about 12% and 6.6%, respectively, while the cold zone shrinks by about 32%. The boundary between the tropics and deserts and other climatic zones expands poleward by about 6.5° latitude on average during April-September in the Northern Hemisphere, the area of most significant change, and by about 1° latitude in other regions between the LGM and present.
In this study, the monsoon climate region is defined as the region where the global climate belt undergoes significant seasonal changes, and changes in the East Asian monsoon climate region are analyzed from the LGM to the present and from the present to the time of global warming. The East Asian monsoon region, particularly the region of significant seasonal dry and wet variations, expands in the north-east direction to about 60°N with global warming, and we confirm the unique trend of this region.
Unsupervised machine learning clustering, the k-means++ method, is applied to surface temperature, precipitation, east-west and north-south wind data, and the spatial distribution of the classified data is used to determine global climate zones and East Asian monsoon climate zones.
From the LGM to the present, climate zones change significantly in the Northern Hemisphere high latitudes. In particular, the cold zone area is reduced by about 37% due to the loss of ice sheets that existed in the LGM. With global warming, the tropics and deserts expand by about 12% and 6.6%, respectively, while the cold zone shrinks by about 32%. The boundary between the tropics and deserts and other climatic zones expands poleward by about 6.5° latitude on average during April-September in the Northern Hemisphere, the area of most significant change, and by about 1° latitude in other regions between the LGM and present.
In this study, the monsoon climate region is defined as the region where the global climate belt undergoes significant seasonal changes, and changes in the East Asian monsoon climate region are analyzed from the LGM to the present and from the present to the time of global warming. The East Asian monsoon region, particularly the region of significant seasonal dry and wet variations, expands in the north-east direction to about 60°N with global warming, and we confirm the unique trend of this region.