Article ID: 2024-033
In mid-December 2023, East Asia experienced an extreme sea-effect snowstorm, with snowfall intensity and snow depth breaking historical records. Based on FengYun (FY) meteorological satellite datasets, the atmospheric circulation, the evolution of the sea-effect clouds, and the marine and atmospheric environments are examined. The results show that the temperature anomalies at 850 hPa from the polar regions to East Asia and the Northwest Pacific exhibited a “positive-negative-positive” pattern in early December, which is in favor of the polar vortex moving away from the polar region to lower latitudes causing cold waves. Caused by the northerly winds over the ocean the sea-effect snowstorm cloud systems exhibit as a wide range of cellular cumulus moving towards the land. The weakening wind speed is beneficial for the maintaining of the sea-effect snowstorm. The average cloud top temperature (CTT) of sea-effect snowstorm clouds over the Shandong Peninsula is from −18 to −10°C, and the cloud top height (CTH) is about 1.5 km, showing significant differences from that of the cold front snowstorm clouds. The precipitation rate from FY-3G precipitation measurement radar (PMR) shows that the precipitation top of the cellular cumulus in the Yellow Sea and the East China Sea is 2.0-2.5 km, and the maximum precipitation rate is 0.5-1.0 mm h−1. The high sea surface temperature (SST) provides warm and humid conditions for the cellular cumulus. The colder air moving into warmer and more humid sea surface can result in higher development of cellular cumulus and increasing precipitation rate. The overall performance is characterized by the higher SST, higher atmospheric humidity layers, higher temperature inversion layers, lower CTT, higher CTH, and greater precipitation intensity on the western coast of Honshu Island in Japan compared to the Shandong Peninsula. Additionally, the topography has impact on the distribution and intensity of sea-effect snowstorm.
