Tuesday, 14 May 2002: 2:30 PM
Spatial Patterns of Soil Moisture Connected to Monthly-Seasonal Precipitation Variability in East Asia
This study investigates spatial patterns of soil moisture and the relations to monthly-seasonal precipitation variability in East Asia. Singular value decomposition (SVD) is used to identity the coupled patterns of the two hydrological properties. The data used in the analyses are obtained from a 10-year simulation with a regional climate model. Among the four leading SVD modes, the patterns consisting of a couple of positive and negative pairs of soil moisture anomalies have significant effects on the subsequent precipitation variations, while those with a certain dominant anomaly of soil moisture over most of China have relatively small effects. This therefore indicates that, although soil moisture has close relationships to precipitation at various spatial scales, it could only significantly contribute to the subsequent monthly-seasonal precipitation anomalies occurring at regional scales (up to about 1000 km). The effects of soil moisture also have seasonal dependence to some extent. The circulation corresponding to the two types of patterns shows generally opposite and identical changes, respectively, between the middle and lower troposphere. The correlations of the SVD expansion coefficient series with soil moisture leading precipitation are much more significant than those of the original data series of the two variables, suggesting that, when applying soil moisture to predicting monthly-seasonal precipitation variations, it would be more valuable to use its spatial patterns than values at individual locations.
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