淮河流域土壤湿度异常的时空分布特征及其与气候异常关系的初步研究

DISTRIBUTION AND VARIATION FEATURES OF SOIL HUMIDITY ANOMALY IN HUAIHE RIVER BASIN AND ITS RELATIONSHIP WITH CLIMATIC ANOMALY

  • 摘要: 利用中国东部1990~2000年旬平均土壤湿度、降水和气温观测资料,通过对0~50 cm层次土壤湿度进行旋转主分量分析 (REOF),重点分析了淮河流域土壤湿度的时空分布特征, 并初步研究了土壤湿度与前期、同期和后期不同时段降水与气温的关系。发现春季以30 cm为界,30 cm以上各层土壤湿度异常的第一旋转空间模态十分相似, 其大值中心主要位于淮河流域,而30 cm以下 (30~50 cm) 各层的第二旋转空间模态与之亦十分类似, 因此称该模态为“淮河型”,而夏季和秋季虽然该模态也很显著, 但特征不如春季突出。该模态在各层次土壤中具有明显的持续性特征,均存在40旬左右的显著周期;并与前期和同期降水(气温)呈显著正 (负) 相关关系,与约半年后的降水 (气温) 呈负 (正) 相关关系。

     

    Abstract: With rotated empirical orthogonal function (REOF) analysis technique, the mainly anomalous spatial features of soil humidity in the 0-50 cm layer of Huaihe River basin and its relationship with precipitation and air temperature in different periods were specially analyzed by using the observed data including dekad averaged soil moisture data, precipitation and air temperature data in the east of China from 1990 to 2000. The results indicate that in the springtime the 30 cm soil layer can be treated as a boundary. From 0 cm layer to 30 cm layer, the first rotated loading vector field in every layer reflects the anomalous soil humidity pattern in the Huaihe river basin, named the pattern structure as "Huaihe river pattern". While from 30 cm layer to 50 cm layer, the second rotated loading vector field in every layer is also quite similar to "Huaihe river pattern". In summer and autumn, the "Huaihe river pattern" is still remarkable but the feature is less prominently than that in spring. It is also found soil moisture anomaly of this pattern in every layer has notable duration and a prominent period of nearly forty dekads. Furthermore, positive (negative) correlation between soil moisture and precipitation (air temperature) during prophase and the same period can be found. Also, negative (positive) correlation between soil moisture and the precipitation (air temperature) of nearly half a year later can by noted.

     

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