Collaborative Research: Snowpack Energy and Mass Balance: Implications for Biogeochemical Feedbacks in Alpine Basins

积雪能量和物质平衡：对高山盆地生物地球化学反馈的影响[j]； Noah Molotch ？加州大学洛杉矶分校？s: T.梅克纳？美国亚利桑那州;j·西克曼？加州大学河滨分校;威廉姆斯先生？由于生物地球化学和水文模型难以耦合，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流域研究表明，高山系统中的氮循环受到积雪动力学的强烈影响，但这种控制的机制尚不明确。一般环流模式表明，未来一个世纪气温的升高将导致山区积雪和融雪的数量和速率发生实质性变化。与此同时，山脉也是热点地区。在逆风、低海拔地区，人为氮排放的局部影响。考虑到气候变化和氮沉降速率，对山区生态系统和供水的影响可能是非线性的，如果没有详细的机制模型，就不可能预测。这项研究将通过量化融雪变异性、水文路径和停留时间以及N循环之间的关系来填补这一关键的知识空白。通过将积雪特性的卫星观测与水文和生物地球化学过程耦合的模型相结合，我们将更广泛地了解这些过程及其对气候变率和变化的反馈的敏感性。15年回顾分析和未来气候情景将用于评估以下问题：1)气候变率如何影响雪-气能量交换和融雪速率和空间格局？2)气候年际变化如何影响水文流动路径和水化学通量？3)在未来气候情景下，水文与元素通量之间的联系将如何变化？这些问题将在美国两个被研究得最好的山区研究地点——加利福尼亚州内华达山脉的托科帕流域和科罗拉多州落基山脉前山脉的绿湖谷——得到解决。在流动路径模型中对融雪的空间明确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下个世纪高山系统对偶发性和慢性酸化的易感性。

Snowpack Energy and Mass Balance: Implications for Biogeochemical Feedbacks in Alpine BasinsPI: Noah Molotch ? UC Los AngelesCo-PI?s: 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.