北非Sahel地区夏季降水异常对华北平原旱涝指示意义

Inspiration of anomalous rainfall in Sahel region to variations of drought and flood in north China Plain in summer

利用NECP/NCAR再分析和气象站点实测降水资料,辅以分段线性回归、趋势分析及相关分析方法,分析了近54a华北平原和Sahel地区的降水变化特征,探讨了Sahel地区夏季降水异常对华北平原旱涝变化的指示意义。结果表明:(1)华北平原与Sahel地区夏季降水异常相关性存在空间差异,显著相关区域位于800mm等降水线以北的地区,淮河平原的相关性较弱;(2)华北平原与Sahel地区降水关系既有稳定性,又存在明显的年代际变化特征。20世纪70年代中期和90年代末为相关性变化的重要转折点,这与NAO,PDO和东亚季风以及青藏高原积雪突变时间一致;(3)地形因素、城市因素对降水相关性影响较弱。在省域尺度上,山东省正相关特征最为突出,表现为全区一致性;京津冀平原区表现为显著正相关,河南省则以负相关为主,江苏、安徽表现为不显著负相关;(4)Sahel中区对黄河下游旱涝具有正向指示意义,Sahel东区对海河平原旱涝具有负向指示意义。

Applying the newly - developed observational data and re - analyzing the data of NCER/ NCAR, and based on piecewise linear regression model, trend analysis and correlation analysis diagnosis methods, this paper attempts to describe the variation characteristics of summer precipitation between north China Plain and Sahel in Af- rica during 1960 - 2013, specifically, the paper aims to analyze anomalous rainfall in Sahel region as inspiration to variations of drought and flood in North China Plain in summer. It is found that, there are obvious spatial differ- ences for the correlative coefficient of precipitation in summer between North China Plain and Sahel in Africa. The significant correlation region is in the Haihe Plain and lower Yellow River, which is located in the north of 800 mm precipitation contour. However, Huaihe Plain has no visible relationship with Sahel. During the period of 1960 - 2013, this relationship was comparatively stable, but it had obvious inter- deeadal variation as well. These inter-decadal shifting points were consistent with NAO, PDO, East Asian summer monsoon and snow cover in the Tibetan Plateau. The influences of topographical factor and urbanization on the change of correlative coefficients are rela- tively weak. At provincial level, a significantly positive and consistent pattern exists in Shandong Province, while positive relevance is presented in Beijing - Tianjin - Hebei Plain region, and mainly negative relevance is presented in Henan Province. But Jiangsu and Anhui provinces are not significantly negatively relevant. Abnormal rainfall in middle of Sahel has a positive indication to lower Yellow River, and abnormal rainfall in eastern Sahel has a nega-tive indication to Haihe Plain.