Sea ice variations in the Tatar Strait, Sea of Japan from 2003 to 2022

Abstract

Analyzing long-term sea ice variations in the Sea of Japan is crucial for regional climate change studies, preventing ice-related disasters, and ensuring maritime safety. However, long-term analyses of sea ice in the Tatar Strait remain limited. This study utilizes the Advanced Microwave Scanning Radiometer for the Earth Observing System and the Advanced Microwave Scanning Radiometer 2 (AMSR-E/2) sea ice concentration data to derive sea ice metrics within the Tatar Strait, a pivotal freezing zone located in the Sea of Japan, spanning the period from 2003 to 2022. The double differencing method is initially applied to calibrate the AMSR-2 product, significantly reducing the errors. The calibrated sea ice dataset is then utilized to investigate the spatiotemporal characteristics and analyze potential factors influencing sea ice variations. The results indicate that, between 2003 and 2022, the sea ice extent and annual average sea ice area in the Tatar Strait exhibited fluctuations without a significant downward trend. However, there was a noticeable decline in the annual maximum sea ice area (−1.02 % per year, r = −0.54, p = 0.02) and sea ice concentration (−0.38 % per year, r = −0.65, p < 0.01). Sea ice conditions generally reach the severe freezing period in early January and last for nearly three months (87.58 ± 10.08 days). The sea ice in the Tatar Strait exhibits significant spatial heterogeneity, with concentrations decreasing from north to south. Most areas show a decreasing trend in sea ice concentration, especially in the northern region and the eastern zone of the central sea, while other regions experience a marginal insignificant increase. The maximum sea ice edge averages 561.34 ± 21.19 km, primarily extending south to around 48.8°N. The significant correlations between sea ice and both air temperature and cumulative freezing degree days suggest that local synoptic factors play a crucial role in influencing sea ice area variations. Furthermore, the correlations between sea ice extent and the West Pacific Subtropical High (WPSH) index during JFM (r = 0.49, p = 0.04) and the Pacific Decadal Oscillation (PDO) index in January (r = 0.51, p = 0.02) indicate that both the WPSH and PDO may play a significant role as large-scale climate factors influencing sea ice variability. These results provide crucial insights for sea ice disaster monitoring, risk management, and regional climate change studies.