Implications of Vegetation Dynamics for Semi-Arid Hydrology: A Basis for Predicting Climate Impacts on Water Resources

植被动态对半干旱水文学的影响： 预测气候对水资源影响的基础PI：John D。艾伯森，杜克大学合作者：尼古拉Montaldo，意大利卡利亚里大学摘要：该项目涉及耦合生态水文动力学的半干旱地中海流域，地表饮用水水库几乎完全依赖于在雨季的地表径流和植被生长是水有限的。 动机集中在观测和预测的冬季降雨量减少，源于大尺度大气环流模式的变化。 目前，预测这些系统的未来水文行为的能力是有限的差距，在了解如何在植被覆盖的变化与降水动力学相互作用，以控制水文响应。拟议的研究将在撒丁岛研究流域测试一套五个重点假设，该研究流域已经仪表化并广泛代表半干旱地中海流域。 该项目建立在PI和意大利合作者过去几年在地中海第二大岛撒丁岛进行的实验和建模研究的基础上。 该项目将增加坡面流实验，以捕捉不同的草覆盖和降雨强度对渗透和径流产生的影响。分析将在三个重叠的时间段内进行，代表：1）密集的实地实验记录（~ 5年以上），2）卫星记录 （~ 20+年）; 3）径流和降水记录（~ 80年）。 分析将包括渗透和蒸散之间可能的权衡。 智力优势：该项目旨在揭示季节性降水模式的变化和可变性如何激发植被动态，以及这些变化如何反过来影响半干旱流域的水文收支。 开发的工具将能够严格预测生态水文系统对气候强迫的反应。 将结果与大尺度环流指数联系起来，预计将提高季节时间尺度的可预测性。此外，地中海气候（如加州）的广泛流行简化了方法和调查结果的可移植性。更广泛的影响：拟议活动的结果将为在地中海降水系统发生系统性变化时规划水资源需求提供直接支持。 本科生和博士在这个项目中接受培训的学生将经历广泛和有意义的跨学科研究经验，包括在国外的合作时期。 初步工作由杜克大学对PI的启动支持提供资金。 杜克大学将提供资金（普拉特奖学金）的本科生研究员的夏季支持。

Implications of Vegetation Dynamics for Semi-Arid Hydrology: A Basis for Predicting Climate Impacts on Water ResourcesPI: John D. Albertson, Duke UniversityCollaborator: Nicola Montaldo, University of Cagliari, ItalyAbstract:This project addresses the coupled eco-hydrologic dynamics of semi-arid Mediterranean watersheds, where the surface drinking-water reservoirs depend almost exclusively on overland flow in the rainy season and where the vegetation growth is water limited. The motivation centers on the observed and projected decreases in winter rainfall, stemming from shifts in large-scale atmospheric circulation patterns. Presently, the ability to predict future hydrologic behavior of these systems is limited by gaps in understanding of how changes in the vegetation cover interact with precipitation dynamics to control the hydrological response. The proposed research will test a set of five focused hypotheses in a Sardinian study basin that is already instrumented and broadly representative of semi-arid Mediterranean watersheds. This project builds on experimental and modeling studies that the PI and Italian collaborator have been conducting for the past several years on Sardinia, the second largest island in the Mediterranean. This project would add overland flow experiments to capture the effect of variable grass cover and rainfall intensity on infiltration and runoff generation. Analysis will be conducted over three overlapping time periods, representing: 1) the intensive field experiment record (~ 5+ years), 2) the satellite record (~ 20+ years), and 3) the streamflow and precipitation record (~ 80 years). Analysis will include possible tradeoffs between infiltration and evapotranspiration. Intellectual Merit: This project is designed to reveal how change and variability in seasonal precipitation patterns excite vegetation dynamics and how these changes in turn impact the hydrological budget of semi-arid watersheds. The tools developed will enable rigorous prediction of the response of eco-hydrological systems to climate forcing. The connection of the results to the large-scale circulation indices is expected to lead to improved predictability at the seasonal time scale. Furthermore, the broad prevalence of Mediterranean climates (e.g. California) simplifies the transferability of the approach and findings.Broader Impacts: The results of the proposed activity will provide direct support for planning water resources needs in the face of systematic changes in Mediterranean precipitation regimes. The undergraduate and Ph.D. students trained on this project will experience broad and meaningful interdisciplinary research experience, including collaborative periods abroad. Preliminary efforts were funded by Duke start-up support to the PI. Duke will provide funding (Pratt Fellowship) for summer support of the undergraduate student researcher.