Analysis of rainfall data to develop the classification criteria for identifying agro-climate resources on the field

Abstract

The issue of climate change demands an update on the existing agro-climate map of Indonesia. For this purpose, in 2019 the Indonesian Agro-climate Resource Map was prepared. One of the stages of mapping is rainfall classification. This paper describes the analysis of rainfall to produce the classification used in the Indonesian Agro-climate Resource Map. The analysis used the monthly and annual rainfall data from 4087 stations with various observation lengths period between 1980-2010. The results of the analysis show that there is a proportional relationship between annual rainfall and the number of consecutive wet months (R2 = 0.776), as well as an inversely proportional relationship between annual rainfall and the number of consecutive dry months (R2 = 0.64), and between the number of consecutive dry months with the consecutive wet months (R2 = 0.72). The results of the rainfall analysis divided the criteria for annual rainfall into 3 categories, namely wet (>2500 mm/year), moderate (1500-2500 mm/year) and dry, (<1500 mm/year); dividing the criteria for dry months into 3 categories, namely <3, 3-7, and >7 months; and dividing the criteria for the number of wet months into 4 categories, namely <3, 3-4, 5-9, >9 months. To improve the adaptation capacity of users and to assist quickly identification in the field, a Triangle Diagram is designed which can be used to identify the value of annual rainfall, the number of consecutive wet months, the number of consecutive dry months and the crop planting patterns.