UJI KONSISTENSI PERKIRAAN DATA CURAH HUJAN YANG KOSONG PADA STASIUN PENGAMATAN CURAH HUJAN WILAYAH DELI SERDANG

Abstract

Rainfall is one of the essential meteorological parameters used for various purposes, such as water resource planning, agriculture and disaster mitigation. However, rainfall data collected often contains gaps due to equipment failure, observer negligence or inadequate data storage conditions. This study aims to estimate missing rainfall data and test its consistency at three observation stations in the Deli Serdang region Sibiru-biru, Tanjung Morawa and Pancur Batu during the period from January to December 2023. Data estimation was conducted using three primary methods: Arithmetic Mean, Normal Ratio and Inversed Square Distance. The results show that the Inversed Square Distance method provided the highest accuracy compared to the other methods, particularly in areas with uneven rainfall distribution. Data consistency was tested using the Double Mass Curve and Rescaled Adjusted Partial Sums (RAPS) methods. The results of the consistency test indicate that the estimated data exhibits consistent patterns, as shown by a linear cumulative curve from the Double Mass Curve method without significant breaks after correction. Additionally, the RAPS method without significant breaks after correction. Additionally, the RAPS method revealed that the cumulative deviation values were within acceptable limits (Q_calcuated < Q_critical and R_calculated < R_critical), ensuring that the data is reliable for further analysis. This study contributes to ensuring the quality of rainfall data for hydrological analysis and water resource management. The findings are expected to serve as a reference for rainfall-related disaster mitigation and support data-driven infrastructure planning.