Teleconnection and climatic oscillation in aquifer water level in Kumamoto plain, Japan

Abstract

AbstractRelative little is known about the interaction between climate change and groundwater. Analysis of aquifer response to climatic variability could improve the knowledge related to groundwater resource variations and therefore provides guidance on water resource management. In this work, seasonal and annual variations of groundwater levels in Kumamoto plain (Japan) and their possible interactions with climatic indices and El Niño Southern Oscillation (ENSO) were analyzed statistically. Results show the following: (1) The water level in the recharge area mainly fluctuates at 1‐ and 2‐year periods, whereas the significant periodicity for water level oscillation in the coastal aquifer is 0.5 year. (2) The aquifer water levels are possibly influenced by variability in precipitation, air temperature, barometric pressure, humidity variances and ENSO. Relative high correlations and large proportions of similarities in wavelet power patterns were found between these variables and water levels. (3) Aquifer response to climatic variances was evaluated using cross wavelet transform and wavelet coherence. In recharging aquifers, the ENSO‐induced annual variations in precipitation, air temperature, humidity and barometric pressure affect aquifer water levels. The precipitation, air temperature and humidity respond to ENSO with a 4‐, 6‐ and 8‐month time lag, respectively, whereas the ENSO imparts weak influence on the barometric pressure. Significant biennial variation of water levels during 1991–1995 is caused primarily by precipitation and humidity variations. In the coastal aquifer, the 0.5‐year variability in ENSO is transferred by precipitation, barometric pressure and humidity to aquifer water levels, and the precipitation/humidity influence is more significant comparing with the barometric pressure. Copyright © 2014 John Wiley & Sons, Ltd.