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| Evaluation of CLIGEN precipitation elements on Loess Plateau |
| Li Zhi1,2,3,Liu Wenzhao1,2,Zhang Xunchang4,Li Shuangjiang1,3,Chen Jie2 |
| 1.Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,2.College of Resources and Environmental Science,Northwest Sci-Tech University of Agriculture and Forestry: 712100,Yangling,Shaanxi;3.Graduate School of the Chinese Academy of Sciences,100049,Beijing:China;4.USDA-ARS Grazinglands Research Laboratory,73036,El Reno,Oklahoma,USA |
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Abstract Among the commonly used stochastic weather generator,CLIGEN is the only one that generates precipitation elements(i.e.precipitation amount,storm duration,time to peak,peak intensity),which will affect the output of hydrological and agricultural response models.Using daily weather data of Changwu weather station from 1957 to 2001,precipitation element data of Wandonggou watershed from 1988 to 2001 and 100 years of CLIGEN generated data,were the ability of the CLIGEN model to reproduce daily,monthly,and(annual) precipitation amounts,probability distribution,extremes,and internal storm patterns(i.e.,storm (duration) and relative peak intensity) were evaluated.Means of daily,monthly,and annual precipitation were(adequately) preserved by CLIGEN and were evaluated absolute relative errors were not more than 1.0%;Standard deviation were all unpredicted and the absolute relative errors were less than 6.6%.Two other probability distributions except daily precipitation were well simulated.Mean absolute relative errors for the all-time maxima of daily,monthly,and yearly precipitation were relatively bigger than corresponding precipitation,suggesting that the ability of predicting extreme need to be improved.The frequencies of wet periods were relatively well replicated by the model,while the frequencies of dry periods less than 20 days have an average relative error of 8.9%.Relative peak intensity generated(ip) by CLIGEN was relatively overestimated than the measured.The CLIGEN-generated durations and precipitation have the similar trend,which were overpredicted for small storms or short duration and underpredicted for large storms or long duration compared with the measured.
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Received: 29 November 2005
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