Reconstruction of the ground surface temperature history from the borehole temperature data in the southeastern part of the Republic of Korea

Abstract

The changes in the temperature on the Earth's surface in the past have penetrated into the subsurface and have been recorded as transient temperature perturbations to the background thermal field. In this study, we reconstruct the ground surface temperature (GST) history of the last 300 years by analysing three borehole temperature profiles in Ulsan, the southeastern part of the Republic of Korea. The borehole temperature profiles show positive temperature anomalies caused by recent warming. The reconstructed GST history showed a cold period in the late 19th century and subsequent warming in the present time. After the cold event, the GST increased by 1.5 K up to 1980. The warming trend from 1900 to 1980 was 2.0 K/century. We compare the GST history with proxy temperature reconstructions obtained by other studies in Northeast Asia. The result suggests spatial variability of the climate in Northeast Asia.