An integrated observational and model‐based analysis of the hydrologic response of prairie pothole systems to variability in climate
An integrated observational and model‐based analysis of the hydrologic response of prairie pothole systems to variability in climate
复制标题
草原坑洼系统对气候变化的水文响应的综合观测和基于模型的分析
DOI：
--
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
F. Schwartz
中科院分区：
文献类型：
--
作者：
Ganming Liu;F. Schwartz
我们开发了一个水文模型，能够模拟由成千上万个或更多的封闭盆地水体组成的坑坑复合体。应用该方法模拟了北达科他州草原坑坑区105年（1901-2005）期间草原坑坑复合体对气候变率的水文响应。通过将模拟结果与观测到的水域面积-频率的幂律关系（来自Landsat图像）以及棉桐湖地区6个湿地27年的水深记录进行比较，利用遗传算法对模型进行了校准和验证。模拟的水体面积和水体频率与平均、干、湿条件下的观测结果吻合较好。对上个世纪模拟结果的分析表明，幂律作为气候的一个函数在年内和年际发生变化。重大干旱和洪水可以在幂律函数中产生显著的变异性（例如，从极端沙尘暴干旱到1993-2001年极端洪水的拦截量可达1.5个数量级的变异性）。分析还表明，小坑和水坑的发生频率不遵循纯粹的幂律行为，偏离线性行为的细节与气候条件密切相关。一个通用方程，既包括大坑洼的线性幂律段，也包括小坑洼和水坑的非线性单峰体，用于建立概念模型，以描述水体数量作为水域面积的函数如何响应气候波动。
We developed a hydrologic model capable of simulating pothole complexes composed of tens of thousands or more individual closed‐basin water bodies. It was applied to simulate the hydrologic response of a prairie pothole complex to climatic variability over a 105 year period (1901–2005) in an area of the Prairie Pothole Region in North Dakota. The model was calibrated and validated with a genetic algorithm by comparing the simulated results with observed power law relationships on water area–frequency derived from Landsat images and a 27 year record of water depths from six wetlands in the Cottonwood Lake area. The simulated behavior in water area and water body frequency showed good agreement with the observations under average, dry, and wet conditions. Analysis of simulation results over the last century showed that the power laws changed intra‐annually and interannually as a function of climate. Major droughts and deluges can produce marked variability in the power law function (e.g., up to 1.5 orders of magnitude variability in intercept from the extreme Dust Bowl drought to the extreme 1993–2001 deluge). Analyses also revealed the frequency of occurrence of small potholes and puddles did not follow pure power law behavior and that details of the departure from linear behavior were closely related to the climatic conditions. A general equation, which encompasses both the linear power law segment for large potholes and nonlinear unimodal body for small potholes and puddles, was used to build conceptual models to describe how the numbers of water bodies as a function of water area respond to fluctuations in climate.