Effects of climate change on dry-wet and its driving factors in the Palu watershed, Indonesia

Abstract

Abstract Assessing dry-wet climate change is very important in the context of global climate change to ensure regional water resources, stabilize ecosystems, and develop socio-economic development. This study aims to investigate the temporal variations in aridity index (AI), precipitation (P), reference evapotranspiration (ET0), and the underlying driving climatic factors. The methodology used includes the aridity index (AI), trend analysis, sensitivity, and contributors. Daily temperature and rainfall data were collected from 5 meteorological stations in the Palu Watershed (Bora, Kalawara, Kulawi, Palolo, Wuasa) from 2002 - 2022. The results show that 84.58% of the Palu watershed experienced wetting while only 15.42% experienced drought during the last two decades. AI changes are mainly determined by changes in the ET0 trend. During observations (2002-2021), ET0 experienced a significant decrease at a rate of 4.08mm/day. The trend of ET0 is negatively affected by a decrease in wind speed and duration of sunlight and is positively affected by a decrease in relative humidity and an increase in air temperature. Air temperature (T) and relative humidity (RH) contribute to increasing ET0 while wind speed (V) and sunshine duration (S) contribute to decreasing ET0.