Collaborative research: Snowpack energy and mass balance: implications for biogeochemical feedbacks in alpine basin

积雪能量和质量平衡：对高山盆地生物地球化学反馈的影响PI：诺亚·莫洛奇0739107加州大学洛杉矶分校co-Pi：0738748 T.Meixner？亚利桑那州大学；J.西克曼？加州大学河滨分校；M.Williams？由于生物地球化学和水文模型的耦合困难，人们对氮(N)生物地球化学的水文强迫知之甚少。内华达山脉和落基山脉的长期集水研究表明，高山系统中的氮循环受到积雪动力学的强烈影响，但这种控制的机制仍不清楚。大气环流模型表明，未来一个世纪气温上升将导致山区积雪和融化的数量和速度发生重大变化。同时，山脉是什么？热点？用于上风、低海拔地区人为N排放的局部影响。考虑到气候和氮沉积速率的变化，对山区生态系统和供水的影响可能是非线性的，如果没有详细的机械模型，就不可能预测。这项研究将通过量化积雪融化的可变性、水文路径和停留时间以及氮循环之间的关系来填补这一关键知识空白。通过将卫星对雪特性的观测与水文和生物地球化学过程相结合的模型相结合，我们将对这些过程的敏感性以及对气候变化和变化的反馈有更广泛的了解。将使用15年回顾分析和未来气候情景来评估以下问题：1)气候变化如何影响雪-大气能量交换以及积雪融化的速度和空间模式？2)气候年际变化如何影响水文径流和水化学通量？3)在未来气候情景下，水文通量和元素通量之间的联系将如何变化？这些问题将在美国研究最深入的两个山地研究地点--加利福尼亚州内华达山脉的托科帕分水岭和科罗拉多州落基山脉前缘山脉的绿色湖泊山谷--解决。流动路径模型中积雪融化的空间显式表示将提高对控制高山系统水化学通量的过程的理解。未来的气候情景将利用这些进展来确定高山系统在下个世纪对间歇性和慢性酸化的敏感性。

Snowpack Energy and Mass Balance: Implications for Biogeochemical Feedbacks in Alpine BasinsPI: Noah Molotch 0739107 UC Los AngelesCo-PI: 0738748 T. Meixner ? U. Arizona; J. Sickman ? UC Riverside; M. Williams ? U. ColoradoAbstractHydrologic forcing of nitrogen (N) biogeochemistry is poorly understood due to difficulties in coupling biogeochemical and hydrologic models. Long-term catchment studies in the Sierra Nevada and Rocky Mountains demonstrate that N cycling in alpine systems is strongly influenced by snowpack dynamics, but mechanisms underlying this control remain undefined. General circulation models indicate that increasing air temperature over the coming century will cause substantial changes in the amounts and rates of snow accumulation and melt in mountainous regions. At the same time, mountains are ?hot-spots? for localized impacts from anthropogenic N emissions in upwind, lower-elevation areas. Given both changing climate and N deposition rates, impacts to mountain ecosystems and water supplies are likely to be non-linear and impossible to predict without detailed mechanistic models. This study will fill this critical gap in knowledge by quantifying relationships among variability in snowmelt, hydrologic pathways and residence times, and N cycling. By merging satellite observations of snow properties with models that couple hydrological and biogeochemical processes we will gain broader understanding of the sensitivity of these processes and feedbacks to climate variability and change. Fifteen-year retrospective analyses and future climate scenarios will be used evaluate the following questions: 1) How does climate variability influence snow-atmosphere energy exchange and the rate and spatial patterns of snowmelt?2) How does inter-annual variability in climate impact hydrologic flow routing and hydrochemical fluxes?3) How will linkages between hydrologic and elemental fluxes change under future climate scenarios?These questions will be addressed in two of the best-studied mountain research sites in the United States - the Tokopah watershed in the Sierra Nevada, California and the Green Lakes Valley in the Rocky Mountain Front Range of Colorado. The spatially explicit representation of snowmelt within flow-path models will improve understanding of the processes that control hydrochemical fluxes of alpine systems. Future climate scenarios will leverage these advances to determine the susceptibility of alpine systems to episodic and chronic acidification for the coming century.