Super Warm Spell is Threatening the Ice and Snow Economy in Harbin, China

This study investigated the direct impact of super warm spells on the ice-snow industry in Northeast China, using the Harbin International Ice & Snow Festival as an example. During the winter of 2001-2025, there were 22 super warm spell days with daily temperatures exceeding 0°C, which is much more frequent than the 5 days observed in 1971-2000. Composite of all the super warm days reveals a clear wave-train pattern from the polar region to the middle latitudes, with three negative anomaly centers located in the west of the Barents Sea, Lake Baikal and the northwestern Pacific, and two positive centers over Northeast China and the Kara Sea. The East Asian trough (EAT) is extremely weak. Of the major East Asian winter monsoon systems, the EAT is most closely related to the temperature in Harbin. By enhancing warm temperature advection in the south and weakening cold temperature advection in the north, the EAT directly influences temperature variations in Northeast China. The EAT weakens more significantly in late winter than in early winter, which is consistent with the intra-seasonal temperature rising trend. This indicates that the EAT may be the dominant factor causing the increase in super warm spells in February.