연구보고서
- 저자
- Dr. Hongwei Yang
- 작성일
- 2016.02.25
- 조회
- 259
- 요약
- 목차
The total amount and frequency of extreme precipitation were analyzed over the Maritime Continent with data from observations, dynamic downscaling of a hindcast experiment forced by the European Centre for Medium–Range Weather Forecasts Reanalysis–Interim dataset, a historical experiment forced by the Hadley Centre Global Environmental Model Version 2–Atmosphere–Ocean (HadGEM2–AO) global coupled model, as well as near future projections from a Representative Concentration Pathway (RCP) 4.5 experiment and far future projection from a RCP 8.5 experiment forced by the future projections of HadGEM2–AO output.
Correlations between observed extreme precipitation and the El Nino Southern Oscillation (ENSO) as well as the Madden–Julian Oscillation (MJO) during the rainy season were quantified over the local lands. We found that the impact of ENSO on extremes is dependent on the MJO phases. ENSO impacts extremes by changing the interannual variation component, while MJO influences the extremes through both the annual cycle and the intraseasonal component of the extreme itself.
The hindcast experiment reasonably simulated the climate's annual cycle of rainfall and extremes. Qualitatively, the impacts of ENSO and MJO on the extremes were correctly reproduced in the hindcast experiment. However, the impact was weaker than that in the observational study. Variation of extremes as a function of ENSO and MJO was generally comparable with the observations, except that the magnitude and spread of the extremes were generally overestimated.
The historical experiment data were capable of representing the annual cycle of rainfall and extremes, but the links between extreme precipitation and ENSO or MJO were not very clear. Nevertheless, the historical experiment generally had larger biases for the extremes than those in the hindcast experiment.
There was no clear trend in the changes of the mean extremes in the future. However, the daily variability of extremes showed an increasing trend over most lands. Over the northern the Indo–China Peninsula (IC), southern IC, Borneo, and Java, large extreme rainfall events will likely become frequent in the future. In contrast, less large extreme rainfall events are forecasted for Luzon and Visayas. No large changes are forecasted over New Guinea. Lastly, Sumatra and Mindanao showed uncertain changes in the future.