Identifying Oldeman’s agroclimatic zones in Tanah Datar, West Sumatra based on CHIRPS (Climate Hazards Group Infrared Precipitation With Station)

Abstract Rainfall conditions in several regions have tended to change due to climate change; therefore, it is necessary to have current and accurate data as the basis for agroclimatic zone classification. With the development of technology, remote sensing (satellites) can be used to obtain representative rainfall data. This research aims to identify and map the Oldeman agroclimatic zones in the Tanah Datar district utilizing Climate Hazards Group Infrared Precipitation with Station (CHIRPS) data. The research was conducted from July to September 2024. This study used a quantitative approach to map the Oldeman agroclimatic zones. The mapping of agroclimatic zones was based on monthly CHIRPS rainfall data (2008-2023) and the administrative shapefile of West Sumatra province. The Oldeman climate classification mapping utilizing CHIRPS data revealed some findings, the Tanah Datar Regency is currently divided into four agroclimatic zones: B1, D1, D2, and D3. The D1 agroclimatic zone is the most dominant, covering an area of 963.17 km 2 (72.09%) out of the total 1,336 km 2 area of Tanah Datar Regency. The areas of the other agroclimatic zones are 152.02 km 2 (11.38%) for Zone D3, 137.31 km 2 (10.28%) for Zone D2, and 83.50 km 2 (6.25%) for Zone B1.