Effects of Extreme Climate Change in 2016 and Its Correlation with EWH Variability in Indonesia

Gravity Recovery and Climate Experiment (GRACE) satellite mission, which is dedicated specifically to the Earth's gravity change monitoring, also can be used to observe water mass variations. GRACE data is provided through temporal mass variations, primarily water volume variations such as surface water and groundwater changes. GRACE satellite data can be obtained in monthly spherical harmonics coefficients depicting the change of surface mass density. This study investigates the effects of extreme climate change during 2016 in Indonesia by utilizing the GRACE data. Here, the surface mass density change is converted into equivalent water height (EWH). Since the amount of rainfall in Indonesia indirectly dominates the water mass variability, the EWH is then compared with the precipitation over the same period of this study. The result showed that during 2016, the highest and lowest EWH was presented in August with the highest value of 23.527 cm over the Aceh region and the lowest EWH of 0.665 cm over the Nusa Tenggara region. The most increased precipitation during 2016 is in the Kalimantan region, with a value of 0.610 mm/hr in February. The lowest one is in the Nusa Tenggara region, with a value of 0.009 mm/hr in August. For comparison with the EWH, the precipitation rates were converted into monthly precipitation in cm. The correlations between EWH and precipitations variabilities showed different results in different study zones, with the highest correlation in zone 6, which covers North Kalimantan. In comparison, the lowest correlation occurred in zone 25, which covers Yamdena and Tragan islands_ area in the Moluccas.