In this paper, the ability of the CFSv2 model to forecast the polar vortex displacements in the stratosphere of the Northern hemisphere is evaluated. We use the ERA-I reanalysis daily data of the potential vortex (pv) and the horizontal wind; vertical wind in the 430, 475, 530, and 600 K in the potential temperature field; and the temperature in the geopotential height at 50 hPa. And the 1–850 hPa isobaric surface temperature and u, v wind field daily data from the 9-month business forecast data of the Climate Forecast System Version 2 (CFSv2). The two polar vortex displacement events shift to Eurasia that occurred in Feb 2008 and Jan 2012. The results show that the polar vortex displacement events in February 2008 and January 2012 shifted toward the European region. During the polar vortex displacements, the westerly wind at 60°N latitude decreases, the temperature gradient reverses at the north polar and 60°N latitudes at 50 hPa, and a weaker stratospheric warming occurs in this process. For two of the polar vortex displacement events, the CFSv2 predictions of the start, largest, and end times of the polar vortex displacement are accurate at forecast lead times of 0 and 5 days, and the prediction results for the westerly winds and temperature gradients are also excellent. However, the CFSv2 prediction ability at forecast lead times exceeding 20 days is poor. For the polar vortex displacement event in February 2008, the CFSv2 predictions are good for the start and largest times but are not consistent with the actual situation for the end time at a forecast lead time of 10 days. The CFSv2 predictions are good for the end time but are not accurate for the start and largest times at a forecast lead time of 15 days. For the polar vortex displacement event in January 2012, the CFSv2 predictions are poor for the start, largest and end times and for the zonal wind, but are good for the temperature gradient during the displacement at forecast lead times of 10 days. The change in the polar vortex boundary and zonal wind and temperature gradients cannot be predicted at forecast lead times of 15 days.

在本文中，评估了CFSv2模型预测北半球平流层极涡旋位移的能力。我们使用ERA-I重新分析潜在旋涡（pv）和水平风的每日数据；潜在温度场中430、475、530和600 K中的垂直风; 温度为50 hPa。来自气候预测系统第2版（CFSv2）的9个月业务预测数据中的1–850 hPa等压面温度和u，v风场每日数据。两个极地涡旋位移事件转移到了2008年2月和2012年1月发生的欧亚大陆。结果表明，2008年2月和2012年1月的极涡旋位移事件向欧洲地区转移。在极涡旋位移中 纬度60°N处的西风减弱，北极和50 hPa处60°N纬度的温度梯度反转，在此过程中平流层变暖变弱。对于两个极地涡旋位移事件，CFSv2对极地涡旋位移的开始，最大和结束时间的预测在0天和5天的预测提前时间上是准确的，而西风和温度梯度的预测结果为也很好。但是，CFSv2在预测交付时间超过20天时的预测能力很差。对于2008年2月的极地涡流位移事件，CFSv2预测对于开始时间和最大时间都是有利的，但与预测时间10天的结束时间的实际情况不一致。CFSv2预测对于结束时间而言是好的，但对于15天的预测提前期来说，对于开始时间和最大时间来说是不准确的。对于2012年1月的极地涡流位移事件，CFSv2的预报在开始，最大和结束时间以及纬向风方面均较差，但对于在预报提前期为10天的位移期间的温度梯度有利。在15天的预报提前期无法预测极地涡旋边界和纬向风与温度梯度的变化。