土地利用/覆被与气候变化下土壤特性动态改变对水文过程的影响

The effects of LUCC (Land-Use and Land-Cover Change) and climate changes on runoff are becoming hot research topics in hydrology. These research efforts are essential for reducing the hazard of flood and drought and are also beneficial to sustainable water use, which are particularly significant in China. As is well known, soil properties are key elements in hydrological processes, and they dynamically change with LUCC and climate changes. Many studies have analyzed the effects of land use change and climate change on hydrological processes in river basins, but most of them have not considered LUCC and climate change effects on soil properties. This project will develop a distributed hydrological model which explicitly considers dynamic changes in soil properties. The mechanics of dynamic changes in soil properties will be analyzed through field surveys and indoor experiments. Relationships between LUCC and climate changes and soil properties will be developed using statistical methods. An agent-based model and time series analysis techniques will be used to develop synthetic LUCC and climate change input data from available downscaled GCM or RCM results. Concurrently, the effects of dynamic soil property changes associated with LUCC and climate scenarios on the hydrological simulations will be estimated from the distributed hydrological model. This project will help improve PUB (Prediction in Ungauged Basin) data development requirements, including parameter transformation and frequency analyses under environment change. It will also lead to improvements in accuracies of hydrological simulation and forecasting models.

土壤特性是影响水文过程的核心要素，且其受到土地利用/覆被变化(LUCC)与气候变化的影响而改变。目前大部分研究土地利用/覆被（LUCC）与气候变化对水文过程的影响却忽略这种土壤特性的动态变化，主要表现在水文过程模拟中对涉及土壤特性参数（如模型中需率定的水力传导度）定为时不变性。针对该问题，本项目将紧紧围绕LUCC与气候变化下土壤特性动态变化规律及其对水文过程的影响开展研究。首先，采用多智能体和时间序列法模拟出LUCC和气候变化的连续过程；其次，在分析LUCC和气候要素对土壤特性影响机理的基础上，建立土壤特性的动态变化模型，结合尺度转换技术与分布式水文模型，构建出土壤特性动态变化下的流域分布式降水径流模型；并揭示未来气候与LUCC综合影响下土壤特性变化规律和水文效应。因此，该项目的研究成果将为变化环境下水文模型参数移植、缺资料流域水文预报、水文模型模拟与预测精度等方面提供理论基础和计算方法。

本项目针对现有降水径流分析中土壤特性时不变性的特点，在综合现有研究成果的基础上，揭示出土壤特性受土地利用/覆被、气候变化影响后的动态变化规律；利用统计、多智能体技术等手段模拟土地利用/覆盖和气候变化过程，并且尤其利用气候变化和土地利用/覆被变化速度的概念，构建出土地利用/覆盖和气候变化下土壤特性改变的降水径流模拟模型，实现考虑土壤特性时间上动态变化下的降水径流模拟，提高了水文模型结构上的时间动态性，进一步增加对降水径流过程的认识和模拟精度的提高，从而为水文预报和水资源系统的适应性管理等方面提供科学支撑和决策支持。