摘要:基于台站观测资料，评估了欧洲中期天气预报中心（ECMWF）最高时空分辨率的第五代大气再分析资料（ERA5）对1979～2018年间中国大陆区域10 m高度风速的气候特征及其变化趋势的再现能力，并同步对比分析了ERA5资料100 m高度风速的特征和长期趋势。结果表明，ERA5资料10 m和100 m风速在空间分布、年—季节—月尺度演变的气候特征方面与台站观测非常一致，10 m风速气候态空间相关系数达到0.66。观测和再分析资料均显示，中国近地层风速呈现出显著的区域性特征，风速大值区主要分布在内蒙古、东北地区西部、新疆北部以及青藏高原西部地区，上述区域的风速季节差异也相对明显，春季风速最大。台站观测、ERA5资料10 m和100 m全国平均风速在4月达到最大值，分别为2.6、3.0、4.5 m s–1，8月为最小值，分别为2.0、2.4、3.5 m s–1。从月平均序列来看，ERA5资料的10 m风速较台站观测偏高0.3～0.5 m s–1，而100 m的风速较10 m风速整体偏高1.2～1.4 m s–1。在风速变化方面，台站观测风速在中国陆地区域整体呈下降趋势–0.4 m s–1（39 a）–1，春季下降趋势最显著[–0.5 m s–1（39 a）–1]，且1979～1992年冬季风速降幅最大[–0.7 m s–1（14 a）–1]，2013年以后风速逐渐增强。ERA5资料两个高度层的风速在整个中国区域均没有明显的长期变化趋势，4个季节风速变化趋势的空间分布与观测也存在差异，100m风速的长期变化趋势与10 m一致但变化幅度大于10 m风速。总之，ERA5资料对中国大陆区域气候平均风速具有较好的再现能力，但无法呈现台站观测风速的长期变化趋势。
关键词:ERA5资料/
10 m风速/
100 m风速/
气候特征/
线性趋势/
中国
Abstract:The ability of the most recently released high spatio-temporal resolution dataset, the fifth generation of European Centre for Medium-Range Weather Forecasts atmospheric reanalysis data (ERA5), to reproduce near-surface wind speed climatology and the linear trend is analyzed over China’s mainland during the period of 1979–2018. Results indicate that the 10-m and 100-m wind speeds are highly consistent with in situ station observations in both spatial distribution and annual–seasonal–monthly evolutions. The spatial correlation coefficient of the 10-m wind speed climatology between ERA5 and station observation is 0.66. The near-surface wind speed shows obvious regional characteristics with strong wind in Inner Mongolia, west of Northeast China, north of Xinjiang, and west of Tibet Plateau. Wind speeds in the above regions also exhibit a seasonal difference with peak intensity observed in spring. The strongest (weakest) national-averaged wind speed obtained from the station observation, 10-m, and 100-m ERA5 reanalysis is 2.6, 3.0, and 4.5 (2.0, 2.4, and 3.5) m s?1 in April (August), respectively. The 10-m ERA5 monthly-mean wind speeds are 0.3–0.5 m s?1 stronger than those of the observation and 1.2–1.4 m s?1 weaker than those of the 100-m wind speed. Since 1979, the observed wind speed shows an overall decreasing trend of ?0.4 m s?1 (39 a) –1. This trend is most obvious in spring [?0.5 m s?1 (39 a)–1], with the biggest drop in the winter of 1979–1992 [?0.7 m s?1 (14a) –1]. Since 2013, the surface wind speed has been increasing. ERA5 reanalysis fails to capture the above decreasing trends in both layers. Moreover, the spatial patterns of the linear trend in four seasons are also different from those of the observations. It is concluded that ERA5 performs well in reproducing the near-surface wind climatology over China but fails to capture the long-term trend.
Key words:ERA5 data/
10-m wind speed/
100-m wind speed/
climatology/
linear trend/
China
PDF全文下载地址:
http://www.iapjournals.ac.cn/qhhj/article/exportPdf?id=a9436237-c1bf-4e8c-b593-a8523df4bde6
