연구보고서
Assessment of EL Nino and Indian Summer Monsoon Rainfall Relationship using Coupled GCMs and MME Approach
- 저자
- Dr. Prabodha Kumar Pradhan
- 작성일
- 2016.01.23
- 조회
- 225
- 요약
- 목차
The warm phase of El Niño Southern Oscillation (El Niño) and Indian Summer Monsoon rainfall (ISMR) relationship is explored through seven fully coupled global climate models (CGCMs), which are semi-operational at APEC Climate Center (APCC). The 23-year (1983-2005) of hindcast datasets of individual model ensembles derived from May initial conditions for southwest monsoon season (JJAS) utilized to find out the simultaneous influence of El Niño -ISMR relationship in 1990s, which is observed to be weaker than present decades. The hindcast of ISMR climatology derived from seven individual models viz. APCC, NCEP, POAMA, SINT, SUT1, PNU and UHT1 appears to be not reasonably well, in particular above 50% departure as shown in CGCMs. In addition, four of six El Niño years during aforementioned period, are well depicts in most of the CGCMs, while the year 1994 and 1997 fails to be well represent by any of these models. The warm SST anomaly aligned with surplus precipitation over tropical equatorial Pacific through five models such as APCC, NCEP, POAMA, SINT and SUT1 are relatively better close toward observation. The El Niño-ISMR teleconnection skills both in monthly to seasonal scale are very poor in PNU as well UHT1 and their RMSE 3.84 and 3.77 less than APCC, NCEP, POAMA, SINT and SUT1 models. The authors show two types of approach Multi-Model Ensemble (MME) by simple composites of ensembles forecast from seven models (APCC, NCEP, POAMA, SINT, SUT1, PNU and UHT1) referred as MME1 and MME2 includes five (APCC, NCEP, POAMA, SINT and SUT1) best performing models. Importantly, anomaly correlation coefficient (ACC) shows the one-month lead MME2 prediction reasonably good for the El Niño and its adverse influence on ISMR than MME1. However, there are some limitations in capturing SST forcing over Indian Oceanic region in both types of MMEs.