论文部分内容阅读
本文利用1979—2011年欧洲中期天气预报中心(ECMWF)的再分析资料(ERA-Interim),运用经验正交函数展开(EOF)和相似系数等方法,对中国地区水分循环诸要素的时空特征进行了计算与分析.研究结果表明:在空间分布特征上,蒸发量、纬向水汽通量和经向水汽通量均与大气可降水量的空间分布最相似,大气可降水量和降水量均与蒸发量的空间分布最相似,降水量与纬向水汽通量的相似系数略大于其与经向水汽通量的相似系数;在时间演变上:年降水量在1979—2002年间,呈现非常显著的上升趋势;在2002—2011年间,呈现显著的下降趋势.年蒸发量在该两个时段的变化趋势与年降水量一致,但均比年降水量明显;年蒸发量在1979—2011年间呈现非常显著的上升趋势,其年际变化明显小于年降水量.可降水量和水汽通量散度在1979—2011年间的长期变化趋势不明显,但可降水量的年际变化呈阶段式增大,水汽通量的年际变化一直较大.纬向与经向水汽通量均存在2—3年为周期的年际变化;此外,纬向水汽通量在1979—2011年间还存在显著的下降趋势.春、秋季的水汽通量都存在显著下降的长期变化趋势,夏、冬季的长期变化趋势不明显.四季都存在2—3年为周期的年际变化.此外,夏季还存在明显的年代际转折.
Based on the ERA-Interim (ECMWF) from 1979 to 2011 and the empirical orthogonal function expansions (EOF) and similarity coefficients, the spatio-temporal features of water cycle elements in China The results show that the spatial distribution of evapotranspiration, zonal water vapor flux and meridional water vapor flux are the most similar to the spatial distribution of atmospheric precipitable water, and both the amount of precipitable water and the amount of precipitation are related to The spatial distribution of evapotranspiration is the most similar, and the similarity coefficient between precipitation and latitudinal water vapor flux is slightly larger than its similarity with meridional water vapor flux. On the evolution of time, the annual precipitation is very significant between 1979 and 2002 Which showed a significant downward trend from 2002 to 2011. The trend of annual evaporation in the two periods coincided with the annual precipitation but both were significantly higher than that of the annual precipitation. The annual evaporation showed a significant difference between 1979 and 2011 And the interannual variability of the precipitable water content and water vapor flux divergence is not obvious between 1979 and 2011. However, the interannual variability of precipitable water is in the stage of And the annual variation of water vapor fluxes is always large.The annual and meridional water vapor fluxes all have annual variation of 2-3 years as a periodicity. In addition, the latitudinal water vapor fluxes also have significant differences between 1979 and 2011 The long-term trends of water vapor fluxes in spring and autumn are significantly decreased, while the long-term trends in summer and winter are not obvious.The interannual variations of 2-3 years are found in all seasons.In addition, The interdecadal turning point.