ISSN:
1365-2389
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
A major problem in using soil-water models for land evaluation is to define which combination of model complexity and sampling density provides the most reliable predictions for a given investment. The overall error which affects the predictions arises from different sources. For instance, one is the error due to spatial estimation of soil data from soil classifications. The paper describes, for two models of different complexity and two soil maps of different resolution, how this error is propagated to the predictions of crop evapotranspiration.Errors arose and were accumulated during the course of the simulations, but they were not amplified. The variance of the errors depended on the climatic conditions of the simulations. Nevertheless, whatever the conditions, uncertainties in soil properties were propagated to the predictions to a lesser extent by the simple model than by the complex one. For example, combining the simple model and the 1/10 000 map required the same experimental investment as combining the complex model and the 1/100 000 map, but the variance of propagated errors was 53% greater for the complex model than for the simple one. Thus, if we consider only the simulation error derived from estimation errors in soil properties and the sampling costs, it is justifiable to use simple models for predicting the soil water balance in space. However, decisions should be based on the overall precision of the simulations which is also affected by other sources of error, such as the error arising from the model itself.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2389.1994.tb00513.x
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