Impact of La Ni?a and La Ni?a Modoki on Indonesia rainfall variability

4th International Symposium on LAPAN-IPB Satellite for Food Security and Environmental Monitoring

农业科学;生态环境科学

Hidayat, R.^1 ; Juniarti, M.D.^1 ; Ma'Rufah, U.^1

Department of Geophysics and Meteorology, Bogor Agricultural University, Bogor, Indonesia^1

关键词: Eastern equatorial Pacific;    Highly-correlated;    Positive rainfall anomalies;    Rainfall variability;    Strong convergence;    Walker circulation;    Weak convergence;    Western Pacific;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/149/1/012046/pdf
DOI  :  10.1088/1755-1315/149/1/012046

来源: IOP

【 摘 要 】

La Niña events are indicated by cooling SST in central and eastern equatorial Pacific. While La Niña Modoki occurrences are indicated by cooling SST in central Pacific and warming SST in western and eastern equatorial Pacific. These two events are influencing rainfall variability in several regions including Indonesia. The objective of this study is to analyse the impact of La Niña and La Niña Modoki on Indonesian rainfall variability. We found the Nino 3.4 index is highly correlated (r = -0.95) with Indonesian rainfall. Positive rainfall anomalies up to 200 mm/month occurred mostly in Indonesian region during La Niña events, but in DJF several areas of Sumatera, Kalimantan and eastern Indonesia tend to have negative rainfall. During La Niña Modoki events, positive rainfall anomaly (up to 50 mm/month) occurred in Sumatera Island, Kalimantan, Java and eastern Indonesia in DJF and up to 175 mm/month occurred only in Java Island in MAM season. La Niña events have strong cooling SST in central and eastern equatorial Pacific (-1.5°C) in DJF. While La Niña Modoki events warming SST occurred in western and eastern equatorial Pacific (0.75°C) and cooling SST in central Pacific (- 0.75°C) in DJF and MAM. Walker circulation in La Niña Modoki events (on DJF and MAM) showed strong convergence in eastern Pacific, and weak convergence in western Pacific (Indonesia).