Spatiotemporal Patterns of Temperature, Precipitation, Wind, and Sunshine Extremes in the Seomjin and Yeongsan River Basins (2020--2023)

Аннотация

Extreme weather poses increasing risks to agriculture in South Korea's Seomjin and Yeongsan River basins. Using observations from the Korea Meteorological Administration's Automated Synoptic Observing System (ASOS) and Automatic Weather Stations (AWS), I investigated spatiotemporal extremes in temperature, precipitation, wind, and sunshine during 2020-2023. Station records were summarized by year and location, and spatial fields were generated with GIS-based interpolation at 30 x 30 m to 270 x 270 m resolution; precipitation fields included PRISM-style topographic adjustments. Both basins exhibited substantial fluctuations in minimum temperatures over the four years. Coastal areas tended to have higher minimum temperatures, consistent with maritime moderation. While extreme daily minimum temperatures differed between even- and odd-numbered years, extreme daily maximum temperatures were relatively stable; nevertheless, basin-average maximum temperatures increased from 34.1 C (2020) to 34.6 C (2021) and 35.3 C (2023). Precipitation extremes varied markedly, with station maxima up to 361.3 mm day-1 (Sunchang, 2020) and gridded maxima of approximately 280 mm day-1 in the Seomjin basin. In the Seomjin basin, northeastern sectors recorded higher daily maximum precipitation than southwestern sectors, likely reflecting topographic controls. Maximum instantaneous wind speeds reached 47.4 m s-1 at Heuksan Island, and daily sunshine duration peaked at 13.6 h at selected coastal stations. We discuss topographic influences and agricultural implications. Because the 4-year period is short, the results are descriptive rather than inferential; we recommend adopting standardized extreme-indices and cross-validated interpolation to improve comparability and uncertainty characterization in future work.