연구보고서
- 저자
- 이은정 연구원
- 작성일
- 2016.01.23
- 조회
- 330
- 요약
- 목차
Forecasting future changes in monsoon precipitation is important because agriculture, water resources, energy, the economy, and society in the world’s most populous monsoon regions are critically influenced by climatic disasters arising from monsoon precipitation variability due to the changing climate. In the fifth phase of the Coupled Model Intercomparison Project (CMIP5), there are various scenarios assuming that radiative forcing will be stabilized with increases of about 2.6, 4.5, 6.0 and 8.5 Wm-2 after 2100. Recently, several studies have revealed that most models in the third phase of CMIP (CMIP3) and CMIP5 project show an increase in global monsoon area and precipitation under global warming, mainly attributable to the increases in moisture convergence and surface evaporation.
We evaluated abilities of coupled general circulation models (CGCMs) in the CMIP5 to simulate the East Asian monsoon system and variables during the reference period of 1979-2005 in terms of simple metrics that were chosen to better understand the physical processes by which large-scale meteorological variables influence the monsoon system. The metrics include: (1) the annual and seasonal mean precipitation and (2) the monsoon precipitation intensity and the threat score in (or over) the monsoon domain. The evaluation metrics mostly consist of global and regional coefficients of spatial pattern correlation and root-mean-squared error between the observed and simulated results. The threat score for the monsoon domain and the spatial correlation of monsoon precipitation intensity were also included.
The number of selected best models for the mean field (BM_M) and seasonal variation (BM_S) were six
and five, respectively. Two best modelgroups are listed as follows: 1) BM_M: ACCESS1-0, CNRM-CM5, FGOALS-g2, IPSL-CM4A-LR, IPSL-CM5B-LR, MRI-CGCM3. 2) BM_S: ACCESS1-0, CCSM4, CESM1-CAM5, MIROC5, MPI-ESM-LR.
The averages of BM_M and BM_S were compared with 28MME, respectively. Variations canceled each other out in 28MME, but BM_M and BM_S demonstrated stronger summer rainfall cores. Though most dominant modes in the three ensemble groups were similar to each other, there are spatially distinct differences. 28MME, BM_M and BM_S demonstrated a weakened magnitude of rainband, a strengthened core over the peninsula and meridional dry spell-rainband dipole mode, respectively. Under the RCP 8.5 scenario, summer precipitation increase in BM_S was the largest among the three groups. There was a big change over the Yellow Sea and near 30-35°N. In terms of low level circulation, southerlies were strengthened among the three ensemble groups. Summer precipitation change in BM_S was large over the Korean peninsula and 30-35°N, compared to the other ensemble groups. This was influenced by the convergence between the strengthened southerly at 120°E and easterly at 30-35°N.