The response of the early winter Northern Hemisphere stratospheric polar vortex and tropospheric Arctic Oscillation to anomalous autumn snow cover in Eurasia is evaluated in four operational subseasonal forecasting models. Of these four models, the two with finer stratospheric resolution simulate a weakened vortex for hindcasts initialized with more extensive snow as compared to those with less extensive snow, consistent with the observed effect, though the modeled effect is significantly weaker than that observed. The other two models fail to capture the local Western Eurasian ridge in response to enhanced snow, and hence their failure to simulate a stratospheric response may be due to biases in representing surface–atmosphere coupling rather than their coarser stratospheric resolution per se. There is no evidence of a tropospheric Arctic Oscillation response in early winter in any of these models, which may be related to the weakness of the stratospheric response or (in one model) to too-weak coupling from the stratosphere down to the surface. Overall, the possible contribution of autumn snowcover over Eurasia to improved predictability of the winter Arctic Oscillation in subseasonal forecast models has not yet been realized even in a probabilistic sense.

欧亚大陆冬季北半球平流层极地涡旋和对流层北极涛动对秋季秋季积雪异常的响应通过四个季节性的亚季节预报模型进行了评估。在这四个模型中，平流层分辨率更高的两个模型模拟了与没有大范围积雪的情况相比，初始大范围积雪引发的后流的减弱涡流，这与所观察到的效果一致，尽管模拟的效果明显弱于所观察到的结果。另外两个模型未能捕捉到因积雪增加而引起的西欧亚大陆脊，因此未能模拟平流层响应可能是由于表层与大气之间的耦合存在偏差，而不是其平流层分辨率本身较高。这些模型中的任何一个都没有证据显示冬季初对流层北极涛动响应，这可能与平流层响应的弱点或（在一个模型中）从平流层到地表的太弱耦合有关。总体而言，在亚季节预报模型中，即使在概率意义上，欧亚大陆上的秋季积雪对冬季北极涛动的可预报性提高的可能贡献也尚未实现。