Southerly Surge Impact on Rainfall Patterns in Southern Indonesia during Winter Monsoon and Madden–Julian Oscillation (MJO)
Trismidianto,
Didi Satiadi,
Wendi Harjupa,
Ibnu Fathrio,
Risyanto,
Elfira Saufina,
Robi Muharsyah,
Danang Eko Nuryanto,
Fadli Nauval,
Dita Fatria Andarini,
Anis Purwaningsih,
Teguh Harjana,
Alfan Sukmana Praja,
Adi Witono,
Ina Juaeni,
Bambang Suhandi
Affiliations
Trismidianto
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Didi Satiadi
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Wendi Harjupa
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Ibnu Fathrio
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Risyanto
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Elfira Saufina
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Robi Muharsyah
Center for Climate Change Information, Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG), Jl. Angkasa I No. 2 Kemayoran, Jakarta Pusat 10610, Indonesia
Danang Eko Nuryanto
Research and Development Center, Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG), Jl. Angkasa I No. 2 Kemayoran, Jakarta Pusat 10610, Indonesia
Fadli Nauval
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Dita Fatria Andarini
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Anis Purwaningsih
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Teguh Harjana
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Alfan Sukmana Praja
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Adi Witono
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Ina Juaeni
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
Bambang Suhandi
Research Center for Climate and Atmospheric, National Research and Innovation Agency, Bandung 40135, Indonesia
The impact of the southerly surge’s interaction with the MJO on rainfall in this study was investigated using daily rainfall data from 2140 weather-observation stations. The southern surge, which coincided with the MJO, enhanced rainfall in the western research region, with Yogyakarta seeing the greatest increase at 4.69 mm/day. Meanwhile, the southern surge that occurred without the MJO increased rainfall in the eastern region, with West Nusa Tenggara seeing the greatest rise at 3.09 mm/day. However, the southerly surge has the effect of lowering rainfall in Jakarta, reaching −2.21 mm/day when the MJO is active and −1.58 mm/day when the MJO is inactive. The southerly surge causes extreme rainfall to only occur in a small part of certain areas, so it tends to significantly reduce the possibility of extreme rainfall. In the southern part of the Indonesian maritime continent, the southerly surge predominates over the MJO, supporting increased water vapor transport. Rainfall mostly increases in the afternoon and decreases in the morning when the southerly surge occurs, whether there is the MJO or not. Convective instability analysis indicates that SS increases precipitation, most likely by raising vertically integrated moisture flux convergence, with a correlation coefficient value of 0.82.
