Difference in the amount and meteorological patterns in the highlands and lowlands in the Galápagos Archipelago

Abstract

Precipitation variability in the Galápagos Islands is crucial for climate change adaptation, biodiversity conservation and water resource management. This study aims to compare the event-scale precipitation characteristics (ESPC), such as intensity, duration and rainfall accumulation at different altitudes during ENSO from 2022 to 2024 on Santa Cruz Island. Precipitation data were used from a new network of automatic weather stations (AWS) installed at five sites: 2, 422 and 849 m a.s.l. on the windward side, and 22 and 619 m a.s.l. on the leeward side. The analysis included two phases: La Niña (April 2022 - January 2023) and El Niño (June 2023 - April 2024). Comparisons was made in two ways: first, the different altitudes within each phase were compared, and second, the two phases were compared at each altitude. For comparison, the distribution of each ESPC and the Mann-Whitney U-test were used to determine whether the differences were significant. For each ENSO phase, less intense and longer duration events occurred at the highest altitude of 849 m a.s.l. Outliers in each ESPC were significantly higher and more frequent during El Niño, especially on the windward side. This study provides a detailed analysis of precipitation characteristics and their variation according to ENSO phases, providing valuable insights for biodiversity conservation and water resource management on the island.