NCEP/NCAR再分析资料在青藏铁路沿线气候变化研究中的适用性

Reliability of NCEP/NCAR Reanalysis Data in Climatic Change along Qinghai-Xizang Railway

通过对青藏铁路沿线8个常规气象站的温度和降水观测资料与NCEP NCAR再分析资料的对比,详细地考查了再分析资料用于青藏铁路沿线气候变化研究的可行性。统计对比分析表明:再分析资料可较好地反映地面气温及降水的年变化特征,可基本反映其年际变率和年际间的差异。然而,再分析的气温值系统性低于实际观测值,降水量则系统性偏大;再分析资料得出的近40年气温长期变化趋势误差较大,降水的长期趋势特别是年降水有一定的参考价值。总体而言,再分析的气温好于降水,青藏铁路沿线主体好于两端,再分析资料可用于青藏铁路沿线主体段年到年际尺度的短期气候变化研究。

The reliability of NCEP/NCAR reanalysis data in the climate change of Qinghai\|Xizang railway line has been investigated by comparing with the observation data from 8 surface meteorological stations. The results show that the annual variation of surface air temperature and precipitation are very well presented through NCEP/NCAR reanalyzed data. The interannual variations of the air temperature at surface are quite well given from NCEP/NCAR reanalysis data. The reanalyzed temperature is more confidence than the reanalyzed precipitation. The results are better in summer than in winter and better in major part of Qinghai\|Xizang railway line than at the two ends of the line. The trends of the surface air temperature analyzed by NCEP/NCAR, however, are completely different with those observed at the surface stations. The trends of the precipitation analyzed by NCEP/NCAR have been showed somehow comparable with the observation. It should be reminded that the NCEP/NCAR reanalyzed temperature values are systematically lower than the observation, but precipitation values higher than the observation.