Evaluation of satellite precipitation products [chirps data] in Peninsular Malaysia using Google Earth Engine (GEE) / Nurul Najwatul Ong Bo Jit @ Husain

The lack of data in areas with few rain gauges to conduct any hydrological study may be overcome through satellite-based precipitation products and reanalysis precipitation products. The global coverage products in the Google Earth Engine (GEE) data analysis platform's repository provide geospatial information that can measure the amount of precipitation. Nevertheless, it is important to evaluate the reliability of the products. Thus, the aim of this study is to evaluate the reliability of satellite and reanalysis precipitation products (CHIRPS Dataset) stored in the GEE repository compared to rain gauge observation from 2011 to 2021 using data from four (4) stations (Cameron Highlands, Bayan Lepas, Subang and Gong Kedak) in Peninsular Malaysia.. The objectives of this study are; i) to determine the trend of the CHIRPS dataset and rain gauge observation from 2011 to 2021 at four (4) selected stations, ii) to determine the correlation of the CHIRPS dataset and rain gauge observation in the years 2011, 2016 and 2021 by monthly and monsoon at four (4) selected stations, iii) to map the precipitation CHIRPS dataset in 2011, 2016 and 2021 in Peninsular Malaysia. A statistical method to measure the strength of the linear relationship between two variables and compute their association called correlation analysis was performed in this study. The results show station Gong Kedak consistent with the highest correlation between rain gauge observations and CHIRPS dataset in 2011 and 2016. In 2021, the highest correlation is station Bayan Lepas. Meanwhile, station Cameron Highlands consistent with the lowest correlation in 2011, 2016 and 2021. All the stations in Inter Monsoon 2 consistent with the higher correlation in 2011, 2016 and 2021. Meanwhile, Southeast Monsoon consistent with the lowest correlation in 2011, 2016 and 2021. In Southeast Monsoon, station Gong Kedak consistent with the lowest correlation in 2011 and 2016. But, in 2021 the with the lowest correlation is Bayan Lepas. In conclusion, CHIRPS data is an alternative that can be used to estimate rainfall distribution in Malaysia.