Identifying effects of local and nonlocal factors of soil water storage using cyclical correlation analysis
β Scribed by Asim Biswas; Bing Cheng Si
- Publisher
- John Wiley and Sons
- Year
- 2012
- Tongue
- English
- Weight
- 136 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0885-6087
- DOI
- 10.1002/hyp.8459
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β¦ Synopsis
Abstract
There are various factors governing the spatial and temporal variability of soil water storage including soil properties, topography and vegetation. Some factors act locally, whereas others act nonlocally, which means that a factor measured at one location has effect on soil water storage at another location. The objective of this study was to examine the effects of local and nonlocal controls of soil water storage in a hummocky landscape using cyclical correlation analysis. Soil water storage, soil properties and terrain indices were measured along a 128βpoint transect of 576βm long from the semiarid, hummocky, prairie pothole region of North America. There are large coefficients of determination (r^2^) between soil water storage and sand content (r^2^β=β0.32β0.53), organic carbon content (r^2^β=β0.22β0.56), depth to carbonate layer (r^2^β=β0.13β0.63), wetness index (r^2^β=β0.25β0.45) and other variables at the measurement scale at different times, indicating strong local effects from these variables. The correlation coefficients were also calculated by physically shifting the spatial series of soil water storage with respect to that of controlling factors. The shifting improves the correlation between the spatial series, and the length of shifting indicated the difference in the response of soil water to its controlling factors. For example, the value of r^2^ increased more than eightfold (r^2^β=β0.47β0.64) after shifting the spatial series of soil water storage by 54βm, almost equal to the average length of existing slope, compared with the very weak correlation (r^2^β=β0.02β0.08) at the measurement scale. This indicated the nonlocal effect from the relative elevation. The identification of nonlocal effects from factors improves the prediction of soil water storage. Copyright Β© 2011 John Wiley & Sons, Ltd.