VALIDATION OF BLENDED DATA FOR UPDATING OLDEMAN’S AGROCLIMATIC ZONE MAP OF BALI PROVINCE

Abstract

Erratic precipitation has recently resulted in changes in the composition of wet or dry months, so the type of climate in an area has also changed. The change causes the level of land suitability for superior commodities to no longer be the same. Knowledge about climate is required by farmers to determine which commodities are suitable for planting time and soil processing. Precipitation data used to create a map of the Oldeman agroclimatic zone in Bali Province have some weaknesses, such as the lack of rain stations and the loss of observation data. Currently, precipitation data are available as a result of rain station data blended with Climate Hazards Group InfraRed Precipitation (CHIRPS) satellite data. Blended data must be validated first before they can be used. This article describes an update to the Oldeman agroclimatic zone map using validated blended data based on 58 grids/locations. The data were validated by 58 rain station data using the correlation coefficient and RMSE. The correlation coefficient method improved values from 0.73 to 0.98 and the level of closeness from strong (8.62%) to very strong (91.38%). The RMSE method improved values from 24.76 to 143.27. The blended data can be used as an alternative to replace the lack or loss of observation data. These new research results improve the update to the Oldeman climate type classification for 1991–2020 based on validated blended data.