Regional calibration of the Pitman model for the Okavango River
Regional calibration of the Pitman model for the Okavango River
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DOI：
10.1016/j.jhydrol.2006.04.047
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发表时间：
2006-11-30
影响因子：
6.4
通讯作者：
Savenije, Hubert H. G.
中科院分区：
文献类型：
--
作者：
Hughes, Denis A.;Andersson, Lotta;Savenije, Hubert H. G.
本文报告了奥卡万戈河流域月径流模型的应用。流量主要来自安哥拉，Cuito河和Cubango河发源于此。然后，它们汇合并穿过纳米比亚/安哥拉边境，流入博茨瓦纳的奥卡万戈湿地。该模型是皮特曼模型的修改版本，包括更明确的地下水和地表水的相互作用。在获得气候数据方面存在重大限制，东部次流域观测流量记录也不够长，这对模型校准构成了巨大挑战。大部分的径流是在潮湿的源头支流，而较低的子流域主要是由通道损失过程中的增量流量的贡献非常小，即使在潮湿的年份。西部支流流量的季节性变化显着较高，基流为主的东部支流相比：观测结果与其地质差异是一致的。该流域被细分为24个子流域，其中18个在其出口处设有计量站。子流域参数值的差异，对应于流域自然地理特征的空间变异性，实现了令人满意的模拟。安哥拉历史降雨量和河流流量数据的长度有限，无法使用分离样本校准/验证试验。然而，卫星生成的降雨量数据，修订，以反映相同的频率特性的历史降雨量数据，用于验证模型对现有的下游流量数据在1990年代。总的结论是，该模型，尽管有限的数据访问，充分代表了流域的水文响应，它可以用来评估未来的发展情景的影响。(c)2006 Elsevier B. V.保留所有权利。
This paper reports on the application of a monthly rainfall-runoff model for the Okavango River Basin. Streamflow is mainly generated in Angola where the Cuito and Cubango rivers arise. They then join and cross the Namibia/Angola border, flowing into the Okavango wetland in Botswana. The model is a modified version of the Pitman model, including more explicit ground and surface water interactions. Significant limitations in access to climatological data, and lack of sufficiently long records of observed flow for the eastern sub-basins represent great challenges to model calibration. The majority of the runoff is generated in the wetter headwater tributaries, while the lower sub-basins are dominated by channel loss processes with very little incremental flow contributions, even during wet years. The western tributaries show significantly higher seasonal variation in flow, compared to the baseflow dominated eastern tributaries: observations that are consistent with their geological differences. The basin was sub-divided into 24 sub-basins, of which 18 have gauging stations at their outlet. Satisfactory simulations were achieved with sub-basin parameter value differences that correspond to the spatial variability in basin physiographic characteristics. The limited length of historical rainfall and river discharge data over Angola precluded the use of a split sample calibration/validation test. However, satellite generated rainfall data, revised to reflect the same frequency characteristics as the historical rainfall data, were used to validate the model against the available downstream flow data during the 1990s. The overall conclusion is that the model, in spite of the limited data access, adequately represents the hydrological response of the basin and that it can be used to assess the impact of future development scenarios. (c) 2006 Elsevier B.V. All rights reserved.