A Study on the Drought Occurrence Characteristics in Volcanic Island Regions: The Case of Jeju Island

Abstract

This study examined the characteristics of drought occurrence in a volcanic island. The study area was chosen to be Jeju island. It was divided into eastern, western, southern and northern regions, taking into account the influence of Halla mountain, to compare and evaluate reginal differences in rainfall and drounght occurrence characteristics (return period, duration). As a result, the rainfall characteristics were significantly different between the southern and eastern regions, as well as between the northern and western regions. Notably, the northern and western regions exhibited a relatively higher likelihood of spring drought occurrence. Futhermore, when comparing drought characteristics, for SPI-3, the average return period during dry months ranged from 6 to 14 months, and the average duration was 1.4 to 2.7 months. Regional differences were relatively minor. However, for SPI-6, the average return period during dry months ranged from 7 to 73 months, and the average duration was 1.5 to 3.2 months, indicatings significant regional differences in drought characteristics. Theses variations underscore the need for region-specific drought response strategies in consideration of the regional features of Jeju island. For SPI-6, where the drought duration does not exhibit significant variation (2-3 months), a common strategy for the entire Jeju region is also indicated.