The impacts of global atmospheric circulations on the water supply in select watersheds in the Indonesian Maritime Continent using SPI

Fauzan Ikhlas Wira Rohmat; Wendi Harjupa; Dede Rohmat; Faizal Immaddudin Wira Rohmat

doi:10.1016/j.heliyon.2023.e15604

The impacts of global atmospheric circulations on the water supply in select watersheds in the Indonesian Maritime Continent using SPI

Heliyon. 2023 Apr 19;9(5):e15604. doi: 10.1016/j.heliyon.2023.e15604. eCollection 2023 May.

Authors

Fauzan Ikhlas Wira Rohmat¹, Wendi Harjupa², Dede Rohmat³, Faizal Immaddudin Wira Rohmat^{1

4}

Affiliations

¹ Water Resources Development Center, Bandung Institute of Technology (ITB), CIBE Building 5th Floor, Jalan Ganesa No. 10, Bandung, 40132, West Java, Indonesia.
² Research Center for Climate and Atmosphere, National Research and Innovation Agency (BRIN), Bandung, 40173, West Java, Indonesia.
³ Department of Geography, Indonesia University of Education (UPI), Jalan Dr. Setiabudhi No. 229, Bandung, 40154, West Java, Indonesia.
⁴ Faculty of Civil and Environmental Engineering Bandung Institute of Technology (ITB), FTSL Building, Jalan Ganesa No. 10, Bandung, 40132, West Java, Indonesia.

Abstract

Despite the diverse atmospheric circulations affecting the Indonesian Maritime Continent (IMC), i.e., El Nino Southern Oscillation-ENSO, Indian Ocean Dipole-IOD, Madden Julian Oscillation-MJO, Monsoon, there is a lack of research on their interaction with hydrological events in watersheds. This study fills this gap by providing insights into the dominant atmospheric events and their correlation with the water supply in three characteristic watersheds, i.e., Tondano (north/Pacific Ocean), Jangka (south/Indian Ocean), and Kapuas (equatorial/interior) in IMC. The research used the standardized precipitation index for the 1-monthly (SPI1), 3-monthly (SPI3), and 6-monthly (SPI3) scale generated from 23 years (2000-2022) of monthly historical satellite rainfall data. The analysis compared each location's SPI indices with the monthly Nino 3.4, Dipole Mode Index (DMI), MJO (100E and 120E), Monsoon index, and streamflow data. The result shows that the dominant atmospheric events for the Tondano watershed were ENSO, IOD, and MJO, with correlation values of -0.62, -0.26, and -0.35, respectively. The MJO event was dominant for the Kapuas watershed, with a correlation value of -0.28. ENSO and IOD were dominant for the Jangka watershed, with correlation values of -0.27 and -0.28, respectively. The monsoon correlated less with the SPI3 in all locations, while it modulates the wet and dry period pattern annually. Most intense dry periods in Tondano occur with the activation of El Nino, while the intense wet period occurs even in normal atmospheric conditions. Most intense wet periods in Jangka occur with the activation of La Nina, while the intense dry period occurs even in normal atmospheric conditions. The occurrence of MJO compensates for the intense wet and dry periods in Kapuas. The correlation among SPI3, atmospheric circulation, and streamflow in the diverse watershed characteristics in the IMC watersheds could give strategic information for watershed management and applies to other watersheds with similar atmospheric circulation characteristics.

Keywords: Atmospheric circulations; Standardized precipitation index; Streamflow; Watersheds.