Partitioning natural and anthropogenic influence on summer temperature over Korea

Abstract

This study focused on Korean summer temperature, which has been increased in the last 100 years with 2.4 ℃. This was known to be caused by multiple factors, including ur-banization and greenhouse gases. In general, we can separate this causes into two catego-ries: natural and anthropogenic factors. Here, by applying multiple linear regression meth-od, we attempt to separate contribution by these two factors on Korean summer tempera-ture. Natural variability is the climate changing naturally from year to year. One of natural variability is El Niño-Southern Oscillation. In this paper, the 200hpa geopotential height expressed natural variability. Anthropogenic factor includes greenhouse gases and urbanization. Greenhouse gases cause global warming, and urbanization causes urban heat island. The difference between the two is that global warming is a global scale and urban heat island is a local scale. Natural variability is the only independent variable to calculate temperature at the first equation, global warming is added at the second equation, and all variables are con-sidered together at third equation. The temperature can’t be explained by the natural influence alone. Second tempera-ture derived from natural variability and global warming has a higher correlation with the observed temperature than first temperature. Second equation simulates mean temperature well but it is not sufficient to explain maximum and minimum temperature. The third equa-tion considering heat island effect together fits well to the maximum and minimum tem-perature. In second derived temperature, the global warming contributes more than 30% at Korean summer temperature. Korean temperature is definitely going to be higher than now because the portion of contribution to temperature by greenhouse gases will increase when the CO2 concentration exceeds 500ppm.