Evaluation of ERA-Interim Monthly Temperature Data over the Tibetan Plateau

• Published in: Journal of mountain science 2014-09, Vol.11 (5), p.1154-1168
• Main Authors: Gao, Lu, Hao, Lu, Chen, Xing-wei
• Format: Article
• Language: English
• Subjects: Air temperature; Climate change; Earth and Environmental Science; Earth Sciences; ECMWF; Ecology; Environment; Geography; Meteorological aircraft; Surface temperature; Temperature; Weather forecasting; Winter; 中期天气预报; 变暖趋势; 气象观测站; 温度数据; 第三代产品; 评价; 青藏高原
• ISSN: 1672-6316; 1993-0321; 1008-2786
• DOI: 10.1007/s11629-014-3013-5

In this study, surface air temperature from 75 meteorological stations above 3000 m on the Tibetan Plateau are applied for evaluation of the European Centre for Medium-Range Weather Forecasts（ECMWF） third-generation reanalysis product ERA-Interim in the period of 1979-2010. High correlations ranging from 0.973 to 0.999 indicate that ERA-Interim could capture the annual cycle very well. However, an average root-meansquare error（rmse） of 3.7°C for all stations reveals that ERA-Interim could not be applied directly for the individual sites. The biases can be mainly attributed to the altitude differences between ERA-Interim grid points and stations. An elevation correction method based on monthly lapse rates is limited to reduce the bias for all stations. Generally, ERA-Interim captured the Plateau-Wide annual and seasonal climatologies very well. The spatial variance is highly related to the topographic features of the TP. The temperature increases significantly（10°C- 15°C） from the western to the eastern Tibetan Plateau for all seasons, in particular during winter and summer. A significant warming trend（0.49°C/decade） is found over the entire Tibetan Plateau using station time series from 1979-2010. ERA-Interim captures the annual warming trend with an increase rate of 0.33°C /decade very well. The observation data and ERA-Interim data both showed the largest warming trends in winter with values of 0.67°C/decade and 0.41°C/decade, respectively. We conclude that in general ERA-Interim captures the temperature trends very well and ERA-Interim is reliable for climate change investigation over the Tibetan Plateau under the premise of cautious interpretation.