VALIDATION AND UTILIZATION OF ECMWF RAINFALL DATA MODEL TO EVALUATE CHANGES OF THE OLDEMAN CLIMATE TYPE IN LOMBOK

• Main Authors: Baihaqi A., Kusnarta I G.M., Yasin I.
• Format: Article
• Language: English
• Published: Russian Journal of Agricultural and Socio-Economic Sciences 2020-08-01
• Series: Russian Journal of Agricultural and Socio-Economic Sciences
• Subjects: validation; utilization; ecmwf; oldeman; double-mass curves
• Online Access: https://rjoas.com/issue-2020-08/article_16.pdf

This study aims for validating and correcting the ERA-Interim ECMWF (European Centre for Medium-Range Weather Forecasts) model data to change observational data that has a short range in the analysis of the changes of the Oldeman climate type in Lombok in the last 40 years. The validation method that has been used in this research is Double-Mass Curves (DMC) by correcting the slope that occurs on the ECMWF rainfall accumulation curve with its observations. The comparing of RMSE values and correlations that occur both before and after the validation process, are used to test the reliability level of the validation method. The results show that there are positive and strong correlations between ECMWF rainfall data and observational data with values ranged from 0.764 to 0.904. RMSE values decreased significantly from 110.1 to 85.4, In general, Lombok Island can be divided into E, D, C and B according to Oldeman climate type. Changes mostly occur in the eastern coastal area which turned wetter (from climate types E to D), the west coast area which became drier (from climate type D to E), and the highlands in the north of the island where the climate type became wetter (from climate type C to B). From those results, we can conclude that the DMC method is highly recommended to be used to validate and correct the ECMWF model data. This also shows that the ECMWF rainfall data is suitable to replace the observational rainfall data for the purpose of climate change analysis after going through a validation and correction process.